Energy and macronutrient intake after gastric bypass for morbid obesity: a 3-y observational study focused on protein consumption

Protein Supplement Tolerability and Patient Satisfaction after Bariatric Surgery

PURPOSE

Disproportional fat-free mass loss often occurs post-bariatric surgery, partly due to insufficient protein intake during the post-surgery recovery phase. We compared five protein-enhancing strategies (PES) on patient tolerability, satisfaction and protein intake.

MATERIALS AND METHODS

Ninety-four participants, scheduled for bariatric surgery, were enrolled and allocated to either of the following: (1) whey powder, (2) hydrolysed collagen powder, (3) plant-based powder, (4) protein-rich products, (5) protein gel, or control. PES groups were instructed to add 30 g of powder or 2 gels or protein products to their diet. Patient satisfaction and tolerability were evaluated with questionnaires. Dietary intake was assessed prior to and during PES use.

RESULTS

Seven patients dropped out (i.e. loss of contact, personal reasons or post-surgery complications) yielding an analytical cohort of 87 participants. The majority of patients (61%) did not experience dietary complaints from PES and could use PES ≥ 5 days of the week. PES non-usage was mainly related to taste dislike (58%). Hydrolysed collagen scored highest on tolerability and satisfaction: 86% of the participants could use HC ≥ 5 days and 71% were satisfied with the product. PES increased protein intake from 54.7 ± 21.5 g/day to 64.7 ± 23.4 g/day during the intervention (p = 0.002), which differed from the control group (+ 10.1 ± 24.5 g/day vs. - 6.3 ± 23.8 g/day for controls, p = 0.019). Whey showed the highest increase, namely + 18.3 ± 16.3 g/day (p = 0.009).

CONCLUSION

PES were tolerated by the majority of participants, and an improved protein intake with PES use was seen. However, the taste of the products could be improved to further enhance satisfaction and tolerability.

Impact of Simulated Caloric Reduction on Nutrient Adequacy Among U.S. Adults with Overweight or Obesity (National Health and Nutrition Examination Survey [NHANES] 2015-2018)

BACKGROUND

Current guidelines for the treatment of obesity recommend dietary restriction to create a caloric deficit, and caloric reductions of 16% to 68% have been achieved in adults with overweight or obesity engaging in intentional weight loss programs.

OBJECTIVES

This study models the impact of simulated caloric reduction on nutrient adequacy among U.S. adults ≥19 y with overweight or obesity using National Health and Nutrition Examination Survey data (2015-2018).

METHODS

Four levels of caloric reduction (20%, 30%, 40%, and 50%) were modeled by prorating daily calorie intake such that usual intakes of 14 nutrients were reduced proportional to caloric reduction. The percentages below the estimated average requirement (EAR) or above the adequate intake (AI) were estimated at each level of caloric reduction, with and without dietary supplement use. Differences across percentages of simulated caloric reductions were determined using nonoverlapping confidence intervals of the means (97.5th percentile confidence intervals were used to approximate P < 0.05).

RESULTS

There were significant differences (P < 0.05) in percentages below the EAR (above the AI) between sequential levels of simulated caloric reduction for most of the nutrients analyzed (protein, vitamins A, B-6, folate, and C, calcium, iron, magnesium, potassium, and zinc). For example, after a simulated 30% caloric reduction, 25%-40% of the population had intakes below the EAR for protein, vitamin B-6, and zinc, and 75%-91% of the population had intakes below the EAR for vitamin A, calcium, and magnesium (vs. 4%-18% and 45%-56%, respectively, without caloric reduction). With the inclusion of dietary supplements, percentages below the EAR for all nutrients (except protein) were lower than those for food alone.

CONCLUSIONS

Caloric reduction may exacerbate nutrient inadequacies among adults with overweight or obesity. Inclusion of nutrient-dense foods, fortified foods, specially formulated products, and/or dietary supplements should be considered for those on calorie-restricted diets for long-term weight loss.

The Role of Dietary Intake in the Weight Loss Outcomes of Roux-en-Y Gastric Bypass and Sleeve Gastrectomy: A Systematic Review and Meta-analysis

The relationship between postoperative dietary intake and weight loss after bariatric surgery remains unclear. We performed a systematic review and meta-analysis of studies published between January 2000 and May 2023, reporting weight loss outcomes, and dietary intake before and after Roux-en-Y gastric bypass and sleeve gastrectomy. A total of 42 studies were included. There was no detectable difference in dietary intake between the two procedures. Roux-en-Y gastric bypass induced an average decrease in energy intake of 886 kcal/day at 12-month post-surgery; however, there was no correlation between daily energy intake and weight loss. These findings show a substantial reduction of energy intake in the first year after bariatric surgery but do not support a link between lower energy intake and greater weight loss.

Effects of Very Low-Calorie Diet versus Roux-en-Y Gastric Bypass Surgery on Body Composition in Patients with Obesity

Roux-en-Y gastric bypass (RYGB) is the most effective treatment for severe obesity. A very low-calorie diet (VLCD) is another effective dietary intervention to treat obesity. This study evaluated the effect of a VLCD versus RYGB on weight reduction, changes in body composition and the resolution of comorbidities during a 12-week period. Individuals with obesity at the obesity clinic, Ramathibodi Hospital, Mahidol University, Thailand with a body mass index (BMI) ≥ 37.5 kg/m2 or ≥32.5 kg/m2 with obesity-related complications were recruited. Treatment options, either RYGB or VLCD, were assigned depending on patients' preferences and physicians' judgment. The analysis included 16 participants in the RYGB group and 15 participants in the VLCD group. Baseline characteristics were similar between groups; nevertheless, the participants in the VLCD group were significantly younger than those in the RYGB group. The number of patients with type 2 diabetes (T2D) was slightly higher in the RYGB group (43.8% vs. 33.3%, p = 0.552). Additionally, patients in the RYGB group had a longer duration of T2D and were treated with anti-diabetic agents, while VLCD patients received only lifestyle modifications. At 12 weeks, total and percentage weight loss in the RYGB and VLCD groups, respectively, were as follows: -17.6 ± 6.0 kg vs. -15.6 ± 5.1 kg (p = 0.335) and -16.2% ± 4.3% vs. -14.1% ± 3.6% (p = 0.147). Changes in biochemical data and the resolution of comorbidities were similar between the groups at 12 weeks. A 12-week VLCD resulted in similar weight loss and metabolic improvement compared with RYGB. Large-scale studies with long follow-up periods are needed to elucidate whether VLCD is a viable alternative treatment to bariatric surgery.

Contribution of Ultra-Processed Foods to Weight Gain Recurrence 5 Years After Metabolic and Bariatric Surgery

BACKGROUND

The aim of this study was to evaluate evolution of ultra-processed food intake and recurrent weight gain in patients who underwent Roux-en-Y gastric bypass.

MATERIALS AND METHODS

This study is an observational longitudinal study that evaluated patients who underwent metabolic and bariatric surgery at four time points: before surgery and at 3, 12, and 60 months after surgery. Anthropometric and dietary intake data were collected through two 24-h dietary recalls. All foods consumed were classified according to degree of processing. Recurrent weight gain was considered the difference between current weight and nadir weight.

RESULTS

The sample consisted of 58 patients with a mean age of 38.7 ± 8.9 years and 68% female. After 60 months, mean excess weight loss and recurrent weight gain were 73.6 ± 27.2% and 22.5 ± 17.4%. Calorie and macronutrient intake decreased significantly between the pre-surgery period, and 3 and 12 months post-surgery; however, there was no significant difference after 60 months. In relation to food groups or macronutrients, no difference was observed between the pre-surgery period and 60 months post-surgery. The contribution of unprocessed or minimally processed foods to calorie intake gradually decreased after 3 months post-surgery.

CONCLUSION

The profile of dietary intake after 60 months of metabolic and bariatric surgery tends to approach that of the pre-surgery period. The contribution of unprocessed and minimally processed foods to calorie intake decreased after 60 months, while ultra-processed food contribution increased.

Adding Branched-Chain Amino Acids and Vitamin D to Whey Protein Is More Effective than Protein Alone in Preserving Fat Free Mass and Muscle Strength in the First Month after Sleeve Gastrectomy

OBJECTIVES

Sleeve gastrectomy (SG) is one of the most commonly performed weight loss (WL) bariatric procedures. The main goal of WL is reducing total body weight (TBW) and fat mass (FM). However, TBW loss is systematically accompanied by a decline in fat-free mass (FFM), predominantly in the first post-surgical month, despite protein supplementation. Branched-chain amino acids (BCAAs) and vitamin D seem to attenuate loss of FFM and, thus, reduce the decline in muscle strength (MS). However, data on the role of an integrated supplementation with whey protein plus BCAAs plus vitamin D (P+BCAAs+Vit.D) vs. protein alone on total weight loss (TWL), fat mass (FM), fat-free mass (FFM), and (MS) in the first month after SG are lacking. Therefore, the present study aims to evaluate the impact of P+BCAAs+Vit.D vs. protein alone supplementation on TWL, FM, FFM, and MS in the first month after SG.

MATERIALS AND METHODS

Before SG and at 1 month afterward, we prospectively measured and compared TBW, FM, FFM, and MS in 57 patients who received either a supplementation with P+BCAAs+Vit.D (n = 31) or protein alone (n = 26). The impact of P+BCAAs+Vit.D and protein alone supplementation on clinical status was also evaluated.

RESULTS

Despite non-significant variation in TBW, FM decreased more significantly (18.5% vs. 13.2%, p = 0.023) with the P+BCAA+Vit.D supplementation compared to protein alone. Furthermore, the P+BCAA+Vit.D group showed a significantly lower decrease in FFM (4.1% vs. 11.4%, p < 0.001) and MS (3.8% vs. 18.5%, p < 0.001) compared to the protein alone group. No significant alterations in clinical status were seen in either group.

CONCLUSION

P+BCAA+Vit.D supplementation is more effective than protein alone in determining FM loss and is associated with a lower decrease in FFM and MS, without interfering with clinical status in patients 1 month after SG.

Associations of change in body fat percentage with baseline body composition and diabetes remission after bariatric surgery

OBJECTIVE

The objective of this study was to determine the role of body fat percentage (BFP) changes in diabetes remission (DR) and the association between baseline body composition and its changes after bariatric surgery.

METHODS

We analyzed 203 patients with type 2 diabetes who underwent Roux-en-Y gastric bypass. Body composition was measured using a gold-standard-derived predictive equation and magnetic resonance imaging. Body composition changes were calculated as 100 × (baseline value - follow-up value)/baseline value. We verified the results in a laparoscopic sleeve gastrectomy cohort with 311 patients.

RESULTS

Compared with non-remission patients in the Roux-en-Y gastric bypass cohort, those who achieved DR showed a higher baseline fat-free mass index (FFMI) and experienced the most significant changes in BFP (p < 0.001). In comparative analyses, BFP changes were significantly better than BMI changes in identifying short- and long-term DR. Linear regression analysis identified FFMI as the most significant baseline variable correlated with BFP changes (p < 0.001). Baseline BMI was positively correlated with changes in BFP but negatively correlated with changes in FFMI. These findings were replicated in the laparoscopic sleeve gastrectomy cohort.

CONCLUSIONS

BFP changes determine DR after bariatric surgery, and baseline FFMI is crucial for BFP changes. A low initial BMI is associated with a smaller BFP reduction and greater FFMI loss after bariatric surgery.

Gut peptides before and following Roux-En-Y gastric bypass: A systematic review and meta-analysis

A systematic search was conducted in Medline Ovid, Embase, Scopus, and Cochrane Central Register of Controlled Trials up until March 2021 following PRISMA guidelines. Studies included evaluated ghrelin, GLP-1, PYY or appetite sensation via visual analogue scales (VASs) before and after Roux-en-Y gastric bypass (RYGB) in adults. A multilevel model with random effects for study and follow-up time points nested in study was fit to the data. The model included kcal consumption as a covariate and time points as moderators. Among the 2559 articles identified, k = 47 were included, among which k = 19 evaluated ghrelin, k = 40 GLP-1, k = 22 PYY, and k = 8 appetite sensation. Our results indicate that fasting ghrelin levels are decreased 2 weeks post-RYGB (p = 0.005) but do not differ from baseline from 6 weeks to 1-year post-RYGB. Postprandial ghrelin and fasting GLP-1 levels were not different from pre-surgical values. Postprandial levels of GLP-1 increased significantly from 1 week (p < 0.001) to 2 years post-RYGB (p < 0.01) compared with pre-RYGB. Fasting PYY increased at 6 months (p = 0.034) and 1 year (p = 0.029) post-surgery; also, postprandial levels increased up to 1 year (p < 0.01). Insufficient data on appetite sensation were available to be meta-analyzed.

Embracing the Pros and Cons of the New Weight Loss Medications (Semaglutide, Tirzepatide, Etc.)

PURPOSE OF REVIEW

The history of multiple weight loss medications has been a concerning paradox based on an increased cardiovascular risk despite significant reductions in adipose tissue and weight. A new class of weight loss medications could change this past narrative based on early preliminary results of cardiovascular risk (not events-still need to be determined) and weight reduction in non-diabetics that acutely competes with results achieved with bariatric surgery. The purpose of this review is to provide a comprehensive summary of the advantages and disadvantages of these newer medications, and how they could impact urology.

RECENT FINDINGS

Weight loss of - 15 to - 20% compared to baseline has become plausible in the short-term and preliminary guidance to reduce acute and chronic adverse events are receiving attention. However, the cost, access, conflicts of interest, supply chain, life-long adherence issues, and the long-term diverse implications on mental and physical health when exposed to this class of medications (GLP-1 agonists) are unknown. The profound caloric reductions should also result in baseline or ongoing nutritional deficiency testing, and general and specific dietary recommendations, which could theoretically mimic some bariatric surgery pre- and post-surgical protocols but has yet to be studied. Regardless, the potential impact of these medicines within a variety of medical specialties needs clinical research. Current and future lifestyle interventions, dietary patterns, and medicines in the weight loss category need to be held to a paradigm whereby cardiovascular health should improve with significant weight loss without a negative impact on mental health. In urology, the ability to impact cancer risk, ED, FSD, incontinence, infertility, nephrolithiasis, and multiple other endpoints are plausible (based on bariatric surgery data) but need preliminary clinical research. Other medicines with a similar or even larger potential impact are in clinical trials, and thus, a concise overview for clinicians and researchers was needed for objective guidance. Currently, comprehensive lifestyle changes utilized with and without these medications continue to garner positive mental, physical, and legacy effects, which suggest that they are as necessary as ever in the treatment of the numerous conditions impacted by unhealthy weight gain.

Protein malnutrition after Roux-en-Y gastric bypass: a challenging case and scoping review of the literature

Although protein malnutrition (PM) is often reported after highly malabsorptive procedures, its exact incidence and mechanisms after Roux-en-Y gastric bypass (RYGB) are poorly understood. The aim of this study was to present a challenging clinical case of PM after RYGB and conduct a scoping review of the literature. Among the 18 studies with 3015 RYGB patients included in the review, the median incidence of PM was 1.7% (range, 0%-8.9%), and it was diagnosed 12 to 120 months after RYGB. The most common cause is insufficient oral intake of protein; however, in cases of persistent hypoalbuminemia, a thorough diagnostic workup needs to be performed. Risk factors for PM after RYGB include specific triggering events such as intractable vomiting and dysphagia, and a total alimentary limb length less than 250 to 300 cm.

Nutritional Status, Selected Nutrients Intake, and Metabolic Disorders in Bariatric Surgery Patients

Bariatric surgery is the most effective treatment for obesity and its complications. However, failure to adhere to dietary recommendations can result in both unsatisfactory weight loss and metabolic disorders. The aim of this study was to evaluate the effects of bariatric surgery on the anthropometric parameters and selected nutrient intake. A total of 12 months postoperatively, percent excess weight loss (%EWL) was significantly higher after laparoscopic Roux-en-Y gastric bypass (LRYGB) than laparoscopic sleeve gastrectomy (LSG) and laparoscopic adjustable gastric banding (LAGB) (93.78% vs. 56.13% and 55.65%, p < 0.001). The same was true for waist-to-hip ratio (WHR) (p = 0.017) and waist-to-height ratio (WHtR) changes (p = 0.022). There was a significant decrease in total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-C) levels after RYGB. A significant decrease (p < 0.05) in daily intake was found for energy (4278.4 kcal vs. 1355.17 kcal), sucrose (122.23 g vs. 38.22 g), dietary fiber (30.90 g vs. 14.20 g), eicosapentaenoic fatty acid and docosahexaenoic acid (EPA+DHA) (142.46 mg vs. 52.90 mg) and % energy from fats (42.43% vs. 35.17%), saturated fatty acids (SAFAs) (19.96% vs. 14.11%) and alpha-linolenic fatty acid (ALA) (0.87% vs. 0.69%). Energy intake and energy % from fats positively correlated with body weight (BW), waist circumference (WC), WHR, and WHtR, and negatively with %EWL. The percentage of unsaturated fatty acids positively correlated with WC and WHR. Energy intake correlated positively with serum triglycerides (TGs) and energy % from fats and carbohydrates. Despite significant weight loss, the patient's diet deviated from recommendations and may have contributed to metabolic disorders.

Evolution of the basal metabolic rate after Roux-en-Y gastric bypass: a systematic review and meta-analysis

Patients who undergo Roux-en-Y gastric bypass (RYGB) exhibit a reduction in total basal metabolic rate (BMR) after surgery, which seems to be intimately related to the amount of postoperative weight loss. The objective was to perform a systematic review and meta-analysis of the literature to determine and evaluate BMR changes after RYGB. The search was performed in certified databases, and the strategy was structured according to the PRISMA ScR. The quality evaluation of the articles included in this review was assessed with two different bias risk tools (ROBINS-I and NIH) according to each study design. Two meta-analyses were elaborated based on the results. 163 articles were selected (from 2016 to 2020), and 9 articles met the inclusion criteria. All of the selected studies evaluated only adult patients, mostly women. Postoperative BMR diminished in all of the included studies after surgery compared to preoperative values. The follow-up periods were 6, 12, 24 and 36 months. Eight articles were used for the meta-analysis after the quality assessment, a total of 434 participants. Compared to baseline values, mean postoperative reductions of 356.66 kcal/d after 6 months (p < 0.001) and 432.89 kcal/d (p < 0.001) after 1 year were observed. The BMR decreases during the first years after Roux-en-Y gastric bypass, especially during the first year postsurgery.

Post-bariatric changes in ingestive behavior: Shift in macronutrient preferences in rats and dynamic adaptation of the within-meal microstructure in humans

This invited review is based on a presentation given at the Annual Meeting of the Society for the Study of Ingestive Behavior in July 2022 and provides the summary of two recent studies on changes in ingestive behavior following bariatric surgery (BS). First, long-term changes in daily absolute and relative macronutrient intake are reported in a rodent model of Roux-en-Y gastric bypass (RYGB). Rats undergoing RYGB progressively decreased their daily calorie- and daily fat intake compared to their preoperative baseline and to the intake of sham operated animals. Second, postbariatric changes in the within-meal ingestive microstructure are portrayed, based on longitudinal data collected in RYGB patients using a drinkometer. The post-RYGB meal size showed a dynamic adjustment process, with the highest decrease in the early postoperative phase, followed by a steady convalescence up to 1-year, at which point the meal size of RYGB patients became comparable to the normal weight adults'. Results are contextualized and contrasted to recent reports on the effect of BS on taste and food choices and consumption. The showcased evidence supports the role of ingestive adaptation and learning in the achievement of reduced calorie intake after RYGB, both in humans and in rodents. The reorganized upper-gastrointestinal anatomy supposedly leads to increased postingestive caloric sensibility, which might be an important behavioral mediator of decreased postbariatric meal size and consequent weight loss.

Brown Adipose Tissue-A Translational Perspective

Brown adipose tissue (BAT) displays the unique capacity to generate heat through uncoupled oxidative phosphorylation that makes it a very attractive therapeutic target for cardiometabolic diseases. Here, we review BAT cellular metabolism, its regulation by the central nervous and endocrine systems and circulating metabolites, the plausible roles of this tissue in human thermoregulation, energy balance, and cardiometabolic disorders, and the current knowledge on its pharmacological stimulation in humans. The current definition and measurement of BAT in human studies relies almost exclusively on BAT glucose uptake from positron emission tomography with 18F-fluorodeoxiglucose, which can be dissociated from BAT thermogenic activity, as for example in insulin-resistant states. The most important energy substrate for BAT thermogenesis is its intracellular fatty acid content mobilized from sympathetic stimulation of intracellular triglyceride lipolysis. This lipolytic BAT response is intertwined with that of white adipose (WAT) and other metabolic tissues, and cannot be independently stimulated with the drugs tested thus far. BAT is an interesting and biologically plausible target that has yet to be fully and selectively activated to increase the body's thermogenic response and shift energy balance. The field of human BAT research is in need of methods able to directly, specifically, and reliably measure BAT thermogenic capacity while also tracking the related thermogenic responses in WAT and other tissues. Until this is achieved, uncertainty will remain about the role played by this fascinating tissue in human cardiometabolic diseases.

Associations of age, sex, and socioeconomic status with adherence to guideline recommendations on protein intake and micronutrient supplementation in patients with sleeve gastrectomy or Roux-en-Y gastric bypass

INTRODUCTION

Patients with bariatric surgery often show poor long-term compliance to recommendations for prevention of nutrient deficiency but it is unclear which factors contribute. We investigated the associations of age, sex, and socioeconomic status (SES) with adherence to guideline recommendations on protein intake and micronutrient supplementation.

METHODS

In a monocentric cross-sectional study we prospectively recruited patients with sleeve gastrectomy (SG) or Roux-en-Y gastric bypass (RYGB) and a minimum postoperative period of 6 months. Clinical and demographic data were obtained from the patients' medical files and by questionnaire. Patients reported on supplement usage, recorded their dietary intake for seven days and underwent physical examinations including blood testing.

RESULTS

We included 35 patients (SG: n = 25, RYGB: n = 10) with a mean (+SD) postoperative period of 20.2 (±10.4) months. Distributions of age, sex and SES were comparable between the SG and RYGB groups. Non-adherence to recommended protein intake was associated with age ≥ 50 years (p = 0.041) but not sex or SES. Protein intake inversely correlated with markers of obesity. There were no significant associations of age or sex with micronutrient supplementation. Only for vitamins A (p = 0.049) and B1 (p = 0.047) higher SES was associated with greater compliance. The only manifest deficiency associated with non-adherence to micronutrient supplementation was that for folic acid (p = 0.044).

CONCLUSION

In patients after bariatric surgery, those of older age and of lower SES might have a greater risk of unfavorable outcome and may require greater attention to micronutrient and protein supplementation.

Effect of physical exercise on muscle strength in adults following bariatric surgery: A systematic review and meta-analysis of different muscle strength assessment tests

Individuals following bariatric surgery are considered at high risk for the development of sarcopenic obesity (excess fat mass, low muscle mass and low physical function), and exercise may play an important role in its prevention and treatment. We systematically reviewed 5 scientific databases (Embase, Medline, Scopus, SPORTDiscus, and Web of Science) and 2 grey literature databases (ProQuest and Google Scholar) for clinical trials that evaluated the effect of exercise on muscle strength in adults following bariatric surgery and conducted a separate meta-analysis for studies that used different muscle strength tests. Random-effect models, restricted maximum likelihood method and Hedges' g were used. The review protocol was registered at the International Prospective Register of Systematic Reviews (PROSPERO) database (CRD42020152142). Fifteen studies were included (638 patients), none had a low risk of bias, and all were included in at least 1 of the 5 meta-analyses (repetition maximum [lower and upper limbs], sit-to-stand, dynamometer, and handgrip tests). Exercise interventions improved both upper (effect size, 0.71; 95% CI, 0.41-1.01; I2 = 0%) and lower (effect size, 1.37; 95% CI, 0.84-1.91; I2 = 46.14) limb muscle strength, as measured by repetition maximum tests. Results were similar for the sit-to-stand (effect size, 0.60; 95% CI, 0.20-1.01; I2 = 68.89%) and dynamometer (effect size, 0.46; 95% CI, 0.06-0.87; I2 = 31.03%), but not for the handgrip test (effect size, 0.11; 95% CI, -0.42-0.63; I2 = 73.27%). However, the certainty level of the meta-analyses was very low. Exercise with a resistance training component performed post bariatric surgery may improve muscle strength, which is related to sarcopenic obesity, functional capacity, and mortality risk, therefore should be included in the follow-up.

Assessment of Physical Activity and Healthy Eating Behaviors Among US Adults Receiving Bariatric Surgery

IMPORTANCE

Bariatric surgery effectively treats severe obesity and metabolic diseases. However, individual outcomes vary depending on sustainable lifestyle change. Little is known about lifestyle patterns after bariatric surgery among the US population.

OBJECTIVE

To compare the level of physical activity and eating behavior among postbariatric surgery patients, individuals eligible for surgery, and those with normal weight.

DESIGN, SETTING, AND PARTICIPANTS

A cross-sectional study using nationally representative survey data from National Health and Nutrition Examination Survey 2015-2018. Respondents included for analysis were age 18 years or older, and categorized by individuals with normal weight, individuals who received bariatric surgery, and individuals clinically eligible for bariatric surgery. Analyses were performed from February to October 2021.

MAIN OUTCOMES AND MEASURES

Self-reported measures were used to assess physical activity (moderate-to-vigorous physical activity [MVPA], sedentary activity, and whether PA guidelines were met) and eating behaviors (total energy intake and Healthy Eating Index [HEI]-2015 diet quality scores).

RESULTS

Of 4659 study participants (mean [SD] age, 46.1 [18.6] years; 2638 [weighted percentage, 58.8%] women; 1114 [weighted percentage, 12.7%] Black, 1570 [weighted percentage, 68.6%] White), 132 (3.7%) reported that they had undergone any bariatric surgery. Median (IQR) time since surgery was 7 (3-10) years. After propensity-score weighting, individuals who underwent bariatric surgery reported more time spent in MVPA than those eligible for surgery (147.9 min/wk vs 97.4 min/wk). Among respondents with normal weight, 45.6% (95% CI, 40.8% to 52.4%) reported meeting PA guidelines, almost 2 times higher than those in the bariatric surgery (23.1%; 95% CI, 13.8% to 32.4%) or in the surgery-eligible group (20.3%; 95% CI, 15.6% to 25.1%). Propensity-score weighted overall HEI was higher for individuals with normal weight (54.4; 95% CI, 53.0 to 55.9) than those who underwent bariatric surgery (50.0; 95% CI, 47.2 to 52.9) or were eligible for the surgery (48.0; 95% CI, 46.0 to 50.0). Across all HEI components, mean scores were similar between the bariatric surgery and surgery-eligible groups. Total energy intake was the lowest among those who underwent bariatric surgery (1746 kcal/d; 95% CI, 1554 to 1937 kcal/d), followed by those with normal weight (1943 kcal/d; 95% CI, 1873 to 2013 kcal/d) and those eligible for bariatric surgery (2040 kcal/d; 1953 to 2128 kcal/d).

CONCLUSIONS AND RELEVANCE

In this cross-sectional study, individuals who underwent bariatric surgery had beneficial lifestyle patterns compared with those eligible for surgery; however, these improvements seemed suboptimal based on the current guidelines. Efforts are needed to incorporate benefits of physical activity and a healthy, balanced diet in postbariatric care.

Early Postoperative Exposure to High-Fat Diet Does Not Increase Long-Term Weight Loss or Fat Avoidance After Roux-en-Y Gastric Bypass in Rats

Background

Bariatric surgery alters food preferences in rats and reportedly decreases desire to consume high-fat high-sugar food in humans. The aim of this study was to investigate whether early post-operative exposure to high-fat food could increase body weight loss after Roux-en-Y gastric bypass (RYGB) by triggering fat avoidance.

Methods

Male Wistar rats underwent either RYGB (n = 15) or sham-operations (n = 16). Preoperatively a standardized 4-choice cafeteria diet [dietary options: low-fat/low-sugar (LFLS), low-fat/high-sugar (LFHS), high-fat/low-sugar (HFLS), high-fat/high-sugar (HFHS)] was offered. First, each option was available for 4 days, thereafter rats were offered the 4 options simultaneously for 3 days preoperatively. Post-surgery, 8 rats in the RYGB- and 8 in the sham-group were exposed to a high-fat content diet (Oatmeal + 30% lard, OM+L) for 10 days, while 7 RYGB rats and 8 sham-rats received OM alone. From the 11th postoperative day, the 4-choice cafeteria diet was reintroduced for 55-days. The intake of all available food items, macronutrients and body weight changes were monitored over 8 weeks. Main outcomes were long-term body-weight and daily change in relative caloric intake during the postoperative cafeteria period compared to the preoperative cafeteria.

Results

During the first 12 days of postoperative cafeteria access, RYGB-rats exposed to OM+L had a higher mean caloric intake per day than RYGB rats exposed to OM alone (Δ10 kCal, P_adj = 0.004), but this difference between the RYGB groups disappeared thereafter. Consequently, in the last 33 days of the postoperative cafeteria diet, the mean body weight of the RYGB+OM+L group was higher compared to RYGB+OM (Δ51 g, P_adj < 0.001). RYGB rats, independently from the nutritional intervention, presented a progressive decrease in daily consumption of calories from fat and increased their daily energy intake mainly from non-sugar carbohydrates. No such differences were detected in sham-operated controls exposed to low- or high fat postoperative interventions.

Conclusion

A progressive decrease in daily fat intake over time was observed after RYGB, independently from the nutritional intervention. This finding confirms that macronutrient preferences undergo progressive changes over time after RYGB and supports the role of ingestive adaptation and learning. Early postoperative exposure to high-fat food failed to accentuate fat avoidance and did not lead to superior weight loss in the long-term.

The effect of protein supplements on weight loss, body composition, protein status, and micronutrients post laparoscopic sleeve gastrectomy (LSG): A Randomised Controlled Trial (RCT)

Background

Low protein intake post-bariatric surgery can result in protein malnutrition, and muscle mass loss. Authors aim to assess the effect of protein supplements on weight loss, body composition, and micronutrient status following LSG.

Methods

This is a double-blinded RCT conducted between February/2017 to January/2018. Eligible post LSG patients were randomized into the intervention group who received daily protein supplements containing 20 g of protein and placebo group received zero protein supplements. Both groups received a standardized diet. Weight loss, body composition, and micronutrient status were analyzed at 1, 3, and 6 months.

Results

48 participants were included in the final analysis (intervention: 21 and placebo:27). Excess weight loss percentage (EWL%) at 6 months was comparable between both groups (69.44 ± 21.99% and 71.40 ± 19.27% respectively). No significant difference observed in the anthropometric parameters. There was an increase in muscle mass and a decrease in muscle mass loss in the intervention group throughout the study period. However, these changes were not statistically significant. There was a significant increase in total protein (P=0.027) and magnesium (P=0.008) in the intervention group at 3 months. Albumin and iron levels were significantly higher at 6 months in the intervention group (P=0.036 & P=0.028 respectively). Other micronutrients did not differ at any time point between both groups.

Conclusion

Protein supplements resulted in significant improvement in total protein, albumin, magnesium, and iron levels post LSG. Although not significant, protein supplements helped in maintaining the muscle mass and preventing muscle mass loss.

Original article

This RCT is an original article and provides a level 2 evidence.

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Low protein intake post-bariatric surgery results in protein malnutrition & muscle mass loss. Protein supplements may be of benefit.

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Eligible post LSG patients were randomized into the intervention group who received daily 20 g protein supplements & placebo group.

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No significant difference in weight, BMI, BMI change, EWL%, TWL%, and absolute weight loss. No statistically significant changes in the muscle mass.

•

Percentage of muscle mass loss was noticeably higher in the control group over the 3 timelines. Fat percentages were less in the intervention group.

•

Total protein and Albumin showed a significant increase in the intervention group.

Lean Mass Loss and Altered Muscular Aerobic Capacity after Bariatric Surgery

INTRODUCTION

Patients undergoing weight loss surgery do not improve their aerobic capacity or peak oxygen uptake (VO2peak) after bariatric surgery and some still complain about asthenia and/or breathlessness. We investigated the hypothesis that a post-surgery muscular limitation could impact the ventilatory response to exercise by evaluating the post-surgery changes in muscle mass, strength, and muscular aerobic capacity, measured by the first ventilatory threshold (VT).

METHODS

Thirteen patients with obesity were referred to our university exercise laboratory before and 6 months after bariatric surgery and were matched by sex, age, and height to healthy subjects with normal weight. All subjects underwent a clinical examination, blood sampling, and body composition assessment by dual-energy X-ray absorptiometry, respiratory and limb muscle strength assessments, and cardiopulmonary exercise testing on a cyclo-ergometer.

RESULTS

Bariatric surgery resulted in a loss of 34% fat mass, 43% visceral adipose tissue, and 12% lean mass (LM) (p < 0.001). Absolute handgrip, quadriceps, or respiratory muscle strength remained unaffected, while quadriceps/handgrip strength relative to LM increased (p < 0.05). Absolute VO2peak or VO2peak/LM did not improve and the first VT was decreased after surgery (1.4 ± 0.3 vs. 1.1 ± 0.4 L min-1, p < 0.05) and correlated to the exercising LM (LM legs) (R = 0.84, p < 0.001).

CONCLUSIONS

Although bariatric surgery has numerous beneficial effects, absolute VO2peak does not improve and the weight loss-induced LM reduction is associated to an altered muscular aerobic capacity, as reflected by an early VT triggering early exercise hyperventilation.

The magnitude and progress of lean body mass, fat-free mass, and skeletal muscle mass loss following bariatric surgery: A systematic review and meta-analysis

Postbariatric loss of muscle tissue could negatively affect long-term health due to its role in various bodily processes, such as metabolism and functional capacity. This meta-analysis aimed to unravel time-dependent changes in the magnitude and progress of lean body mass (LBM), fat-free mass (FFM), and skeletal muscle mass (SMM) loss following bariatric surgery. A systematic literature search was conducted in Pubmed, Embase, and Web of Science. Fifty-nine studies assessed LBM (n = 37), FFM (n = 20), or SMM (n = 3) preoperatively and ≥1 time points postsurgery. Random-effects meta-analyses were performed to determine pooled loss per outcome parameter and follow-up time point. At 12-month postsurgery, pooled LBM loss was -8.13 kg [95%CI -9.01; -7.26]. FFM loss and SMM loss were -8.23 kg [95%CI -10.74; -5.73] and -3.18 kg [95%CI -5.64; -0.71], respectively. About 55% of 12-month LBM loss occurred within 3-month postsurgery, followed by a more gradual decrease up to 12 months. Similar patterns were seen for FFM and SMM. In conclusion, >8 kg of LBM and FFM loss was observed within 1-year postsurgery. LBM, FFM, and SMM were predominantly lost within 3-month postsurgery, highlighting that interventions to mitigate such losses should be implemented perioperatively.

Roux-en-Y Gastric Bypass and Caloric Restriction but Not Gut Hormone-Based Treatments Profoundly Impact the Hypothalamic Transcriptome in Obese Rats

BACKGROUND

The hypothalamus is an important brain region for the regulation of energy balance. Roux-en-Y gastric bypass (RYGB) surgery and gut hormone-based treatments are known to reduce body weight, but their effects on hypothalamic gene expression and signaling pathways are poorly studied.

METHODS

Diet-induced obese male Wistar rats were randomized into the following groups: RYGB, sham operation, sham + body weight-matched (BWM) to the RYGB group, osmotic minipump delivering PYY3-36 (0.1 mg/kg/day), liraglutide s.c. (0.4 mg/kg/day), PYY3-36 + liraglutide, and saline. All groups (except BWM) were kept on a free choice of high- and low-fat diets. Four weeks after interventions, hypothalami were collected for RNA sequencing.

RESULTS

While rats in the RYGB, BWM, and PYY3-36 + liraglutide groups had comparable reductions in body weight, only RYGB and BWM treatment had a major impact on hypothalamic gene expression. In these groups, hypothalamic leptin receptor expression as well as the JAK-STAT, PI3K-Akt, and AMPK signaling pathways were upregulated. No significant changes could be detected in PYY3-36 + liraglutide-, liraglutide-, and PYY-treated groups.

CONCLUSIONS

Despite causing similar body weight changes compared to RYGB and BWM, PYY3-36 + liraglutide treatment does not impact hypothalamic gene expression. Whether this striking difference is favorable or unfavorable to metabolic health in the long term requires further investigation.

Resistance Training Improves Muscle Strength and Function, Regardless of Protein Supplementation, in the Mid- to Long-Term Period after Gastric Bypass

Inadequate protein intake and low levels of physical activity are common long-term sequelae after bariatric surgery and can negatively affect muscle strength (MS) and physical function (PF). The study investigated the effects of resistance training with or without protein supplementation on MS and PF. The study, which involved a 12-week controlled trial (n = 61) of individuals 2-7 years post-Roux-en-Y gastric bypass (RYGB), comprised four groups: whey protein supplementation (PRO; n = 18), maltodextrin placebo (control [CON]; n = 17), resistance training combined with placebo (RTP; n = 11), and resistance training combined with whey protein supplementation (RTP+PRO; n = 15). An isokinetic dynamometer was used to measure MS (peak torque at 60°/s and 180°/s). PF was measured with the 30-s sit-to-stand (30-STS), 6-min walk (6-MWT), and timed up-and-go (TUG) tests. There were improvements in the absolute and relative-to-bodyweight peak torque at 60°/s and 180°/s, TUG, 6-MWT and 30-STS in the RTP and RTP+PRO groups, but not in the CON and PRO groups. Changes in MS were significantly correlated with changes in PF between the pre- and post-intervention periods. A supervised resistance training program, regardless of protein supplementation, improved MS and PF in the mid-to-long-term period after RYGB and can lead to clinical benefits and improved quality of life.

A Comparison of Total Food Intake at a Personalised Buffet in People with Obesity, before and 24 Months after Roux-en-Y-Gastric Bypass Surgery

Long-term reductions in the quantity of food consumed, and a shift in intake away from energy dense foods have both been implicated in the potent bariatric effects of Roux-en-Y gastric bypass (RYGB) surgery. We hypothesised that relative to pre-operative assessment, a stereotypical shift to lower intake would be observed at a personalised ad libitum buffet meal 24 months after RYGB, driven in part by decreased selection of high energy density items. At pre-operative baseline, participants (n = 14) rated their preference for 72 individual food items, each of these mapping to one of six categories encompassing high and low-fat choices in combination with sugar, complex carbohydrate or and protein. An 18-item buffet meal was created for each participant based on expressed preferences. Overall energy intake was reduced on average by 60% at the 24-month buffet meal. Reductions in intake were seen across all six food categories. Decreases in the overall intake of all individual macronutrient groups were marked and were generally proportional to reductions in total caloric intake. Patterns of preference and intake, both at baseline and at follow-up appear more idiosyncratic than has been previously suggested by verbal reporting. The data emphasise the consistency with which reductions in ad libitum food intake occur as a sequel of RYGB, this being maintained in the setting of a self-selected ad libitum buffet meal. Exploratory analysis of the data also supports prior reports of a possible relative increase in the proportional intake of protein after RYGB.

A systematic review and meta-analyses of food preference modifications after bariatric surgery

This systematic review and meta-analyses aimed to synthesize evidence of the link between bariatric surgery and changes in food preferences, considering the method of assessment. MEDLINE, Cochrane Library, Web of Science, Cinahl, PsychINFO, ProQuest, and Open grey were searched incorporating two blocks of terms ("Intervention" and "Food Preferences"). Interventional or observational studies involving patients (BMI ≥ 35 kg m^-2 ) with sleeve gastrectomy (SG) or Roux-en-Y Gastric Bypass (RYGB) and a control group were included. Meta-analyses were performed comparing the standardized daily mean percentage energy from proteins, carbohydrates, and lipids between preoperative and postoperative patients. Fifty-seven studies concerning 2,271 patients with RYGB and 903 patients with SG met the inclusion criteria, of which 24 were eligible for meta-analysis. Despite a total reduction in macronutrient intakes, the meta-analyses revealed a postoperative increase in percentage energy from proteins at 12 months (0.24, 95% CI: 0.03, 0.46, {I² } = 73%) and a decrease in percentage energy from fat at 1 month (-0.47, 95% CI: 0.86, 0.09, {I² } = 72%), up to 24 months (-0.20, 95% CI: -0.31, 0.08, {I² } = 0%). In conclusion, the present systematic review and meta-analyses showed changes of food preferences in terms of macronutrient, food selection and, overall food appreciation up to 5 years following bariatric surgery.

The Effect of Protein Consumption on Fat-Free Mass, Fat Mass, and Weight Loss 1 Year After Sleeve Gastrectomy and Roux-en-Y Gastric Bypass

OBJECTIVE

Sleeve gastrectomy (SG) and Roux-en-Y gastric bypass (RYGB) both limit protein and calorie intake and result in loss of fat-free mass (FFM), fat mass (FM), and weight. This study examined protein consumption and body composition changes after bariatric surgery.

METHODS

A prospective study of patients undergoing SG and RYGB between January 1 and December 31, 2016, with 1-year follow-up. Dietary, body composition, and physical activity data were collected at 3, 6, and 12 months post-operatively by bioelectric impedance and food records. Clinical laboratory data were obtained pre- and post-surgery.

RESULTS

One hundred and five patients (62 [59%] SG and 43 [41%] RYGB) were included in this study. Mean age was 31.8 ± 7.22 years. TWL% after 1 year in SG was 27.11% (p < 0.001) and that in RYGB was 30.41% (p < 0.0001). Reported protein consumptions after RYGB increased from 41.59 ± 22.86 g/day at 3 months (p = 0.004) to 57.90 ± 19.24 g/day at 12 months compared to 52.36 ± 25.04 g and 53.54 ± 29.75 g in SG. Similarly, energy intake after RYGB at 3 and 12 months increased from 895.9 ± 422.61 to 1188.15 ± 463.86 kcal/day compared to 1007.67 ± 422.62 to 1068 ± 575.89 kcal/day after SG (p = 0.009). There was a significant loss of fat-free mass and muscle mass in SG patients at 3 and 12 months from 61.58 ± 3.61 kg and 58.47 ± 3.09 kg to 54.18 ± 11.05 (p < 0.001) and 51.55 ± 10.62 (p = 0.004) but not in RYGB patients. Physical activity levels were similar in SG and RYGB patients.

CONCLUSION

There was a significant preservation of muscle mass after RYGB. Protein intake in majority of the patients was below 60 g/day during the first year after SG and RYGB.

Evaluation of Dietary Assessment Tools Used in Bariatric Population

Severe obesity is associated with major health issues and bariatric surgery is still the only treatment to offer significant and durable weight loss. Assessment of dietary intakes is an important component of the bariatric surgery process. Objective: To document the dietary assessment tools that have been used with patients targeted for bariatric surgery and patients who had bariatric surgery and explore the extent to which these tools have been validated. Methods: A literature search was conducted to identify studies that used a dietary assessment tool with patients targeted for bariatric surgery or who had bariatric surgery. Results: 108 studies were included. Among all studies included, 27 used a dietary assessment tool that had been validated either as part of the study per se (n = 11) or in a previous study (n = 16). Every tool validated per se in the cited studies was validated among a bariatric population, while none of the tools validated in previous studies were validated in this population. Conclusion: Few studies in bariatric populations used a dietary assessment tool that had been validated in this population. Additional studies are needed to develop valid and robust dietary assessment tools to improve the quality of nutritional studies among bariatric patients.

Nutritional Inadequacies Among Post-bariatric Patients During COVID-19 Quarantine in Sao Paulo, Brazil

Post bariatric control of food intake is influenced by psychological and behavioral factors. We investigated dietary habits and food intake during COVID-19 quarantine among recently operated patients. Patients were assessed for total and per meal energy and macronutrient intake as well as frequency of food consumption per processing level. Patients were also classified according to adherence to nutritional recommendations from our outpatient clinic. Main results are indicative of inappropriate nutritional intake during COVID-19 quarantine in postoperative bariatric patients. We observed that many patients failed to meet the recommended protein intake (89.2%) along a relatively high intake of ultra-processed foods (~1/4 of the diet). Our data suggest the need for the implementation of strategies to extend nutritional care to at-risk patients during social distancing.

The Relationship Between Bariatric Surgery and Diet Quality: a Systematic Review

BACKGROUND

Bariatric surgery is currently the most effective treatment for morbid obesity. These procedures change the gastrointestinal system with the aim of reducing dietary intake. Improving diet quality is essential in maintaining nutritional health and achieving long-term benefits from the surgery. The aim of this systematic review was to examine the relationship between bariatric surgery and diet quality at least 1 year after surgery.

METHODS

A systematic search of five databases was conducted. Studies were included that reported diet quality, eating pattern, or quality of eating in adult patients who had undergone laparoscopic-adjusted gastric banding (LAGB), Roux-en-Y gastric bypass (RYGB), and sleeve gastrectomy (SG) procedures. Data was extracted to determine the relationship between having had bariatric surgery and subsequent diet quality.

RESULTS

A total of 34 study articles (described in 36 articles) met the inclusion criteria. The majority of studies were observational in nature and showed a reduction in energy intake following surgery, as well as inadequate intakes of micronutrients and protein, and an excessive intake of fats. There was evidence of nutrient imbalances, suboptimal compliance with multivitamin and mineral supplementation, and limited follow-up of patients.

CONCLUSION

The current evidence base suggests that despite being effective in reducing energy intake, bariatric surgery can result in unbalanced diets, inadequate micronutrient and protein intakes, and excessive intakes of fats. In combination with suboptimal adherence to multivitamin and mineral supplementation, this may contribute to nutritional deficiencies and weight regain. There is a need for high-quality nutrition studies, to identify optimal dietary compositions following bariatric surgery.

Neonatal Outcomes of Pregnancy Following Roux-en-Y Gastric Bypass: a Matched Case-Control Study

PURPOSE

To compare perinatal outcomes and to assess the predictors of birth weight (BW) after Roux-en-Y gastric bypass (RYGB) to those women unexposed to bariatric surgery.

MATERIALS AND METHODS

Singleton births from women submitted to RYGB (BSG) were matched to two control births by maternal age, delivery year, and gender. Control group 1 (CG1) and control group 2 (CG2) were selected according to the prepregnancy body mass index (BMI) < 35 kg/m² and ≥ 35 kg/m², respectively, without previous bariatric surgery.

RESULTS

Fifty-eight pregnancies were evaluated in each group (n = 174). Neonates born after RYGB presented lower BW compared to CG1 (mean difference - 182.3 g; 95% CI - 333; - 31, P = 0.018) and CG2 (mean difference - 306.6 g, 95% CI - 502; - 111, P = 0.02). Although gestational age (GA) was similar (P = 0.219), fetal growth rate (in grams) per gestational week was higher in CG2 (β = 196.27, P < 0.001) vs. BSG (β = 127.65, P < 0.001), irrespective of gestational weight gain (GWG). Pregnancies post-RYGB showed lower GWG, lower BW, and higher prevalence of cesarean section than CG1 and were associated with lower BW, smaller cephalic perimeter, lower prevalence of macrosomia, hypertension, and gestational diabetes than CG2.

CONCLUSION

Birth weight was higher in neonates from women with higher prepregnancy BMI, as compared to births from women submitted to RYGB, irrespective of GWG. Although nearly half of the RYGB mothers were classified with obesity at conception, those pregnancies were associated with better obstetric and neonatal outcomes than among women with prepregnancy BMI ≥ 35 kg/m² who had never undergone RYGB.

Bariatric Surgical Alterations in Tolerability, Enjoyment and Cravings in the Diet (BSATED) instrument: A new scale to measure food preferences following bariatric surgery

Bariatric surgery is associated with changing food preferences, but it is not known whether these changes differ by type of operation or are associated with weight loss. The current study presents validation results for a new 27-item scale, Bariatric Surgical Alterations in Tolerability, Enjoyment and Cravings in the Diet (BSATED). This scale measured enjoyment, craving, and intolerance changes for nine food and beverage categories common to dietary habits in the Southern California region of the U.S. one year following bariatric surgery in the Bariatric Experience Long Term (BELONG) study. Validation of BSATED was done using exploratory factor analyses, construct validity with other conceptually related survey instruments, and criterion validity using hypothesized differences for operation type and percent total weight loss (%TWL) at 12-18 months after surgery. Participants (n = 999) were 86% female, 41% non-Hispanic White, with a mean age of 43.1 ± 11.3 years and a body mass index (BMI) of 43.4 ± 6.8 kg/m² at the time of surgery. Participants reported less enjoyment and craving for high-fat meats (62%), grains (54%), candy and other desserts (e.g. candy bars, chocolate, ice cream) (52%), and sweet baked goods (48%) 12 months after surgery. These changes were more common among participants undergoing Roux-en-Y gastric bypass (RYGB) compared to those receiving sleeve gastrectomy (SG). Participants who reported decreased enjoyment and craving for foods and beverages that post-bariatric patients are counseled to reduce or avoid had greater %TWL at 12-18 months following surgery (p < .001 and p = .003 respectively). The foods and beverages in BSATED that post-bariatric patients are counseled to reduce or avoid could be used to understand how changes in enjoyment, craving and tolerability of these foods/beverages contribute to weight loss following surgery.

Effects of Resistance Training With or Without Protein Supplementation on Body Composition and Resting Energy Expenditure in Patients 2-7 Years PostRoux-en-Y Gastric Bypass: a Controlled Clinical Trial

BACKGROUND

Resistance training (RT) and adequate protein intake are recommended as strategies to preserve fat-free mass (FFM) and resting metabolic demand after bariatric surgery. However, the effect of both interventions combined in the late postoperative period is unclear. This study investigated the effects of RT, isolated and combined with protein supplementation, on body composition and resting energy expenditure (REE) in the late postoperative period of Roux-en-Y gastric bypass (RYGB).

METHODS

This controlled trial involved patients who were 2-7 years postRYGB. Participants were partially matched on body mass index (BMI), age, sex, and years after surgery, and divided into four groups, placebo maltodextrin (control [CON]; n = 17), whey protein supplementation (PRO; n = 18), RT combined with placebo (RTP; n = 13), and RT combined with whey protein supplementation (RTP + PRO; n = 15)-considering the participants who completed the protocol. REE was measured by indirect calorimetry and body composition by multifrequency electrical bioimpedance.

RESULTS

Participant characteristics (40.3 ± 8.3 years old; average BMI 29.7 ± 5.3 kg/m²; 88.9% females) were similar among groups. The RTP+PRO group showed an increase of 1.46 ± 1.02 kg in FFM and 0.91 ± 0.64 kg in skeletal muscle mass (SMM), which was greater than the equivalent values in the CON group (- 0.24 ± 1.64 kg, p = 0.006 and - 0.08 ± 0.96 kg, p = 0.008, respectively). There was no significant time-by-group interaction for absolute or relative REE.

CONCLUSION

Combined RT and adequate protein intake via supplementation can increase FFM and SMM in the late postoperative period without changing REE. These associated strategies were effective in improving muscle-related parameters and potentially in improving the patients' physical function.

Long-term effect of bariatric surgery on body composition in patients with morbid obesity: A systematic review and meta-analysis

We performed a meta-analysis to provide quantitative estimates of fat mass (FM) and fat-free mass (FFM) changes in patients following bariatric surgery over 1 year. A systematic search of PubMed, SCOPUS and Web of Science databases was conducted; the pooled weighted mean difference (WMD) and 95% confidence intervals (CI) were calculated using a random-effects model. Thirty-four studies including Roux en-Y gastric bypass (RYGB), sleeve gastrectomy (SG) biliopancreatic diversion (BPD) and gastric banding (GB) were analyzed. RYGB decreased in body FM (-28.99 kg [31.21, -26.77]) or FM% (-12.73% [-15.14, -10.32]) or FFM (-9.97 kg [-10.93, -9.03]), which were greater than SG and GB. Moreover, the FFM% in RYGB group (11.72% [7.33, 16.11]) was more than SG (5.7% [4.44, 6.95]) and GB (8.1% [6.15, 10.05]) groups. Bariatric surgeries, especially RYGB, might be effective for a decrease in FM and maintenance of FFM in patients with morbid obesity in over 1 year.

Bariatric surgery affects obesity-related protein requirements

CONTEXT

Following bariatric surgery, protein deficiency intakes are reported in morbidly obese patients, whereas post-bariatric protein requirements are not specifically defined with validated method in this population.

OBJECTIVE

To assess average protein requirement (APR) in obese subjects, before, 3 months and 12 months after bariatric surgery using the validated method of nitrogen balance.

DESIGN AND SETTING

Prospective longitudinal study conducted in 21 morbidly obese patients (BMI 43.9 ± 1.4 kg/m²) before (M0), 3 months (M3) and 12 months (M12) after sleeve gastrectomy or Roux-en-Y gastric by-pass. An additional larger cross-sectional study was performed to validate APR before surgery in non-operated matched obese patients (n = 106). APR was evaluated at M0, M3, M12 by measuring 3 days dietary intakes together with losses of nitrogen in urine and stools.

MAIN OUTCOME MEASURE

APR was defined as the mean value of protein intake required to achieve balance nitrogen equilibrium.

RESULTS

Before surgery, APR in morbidly obese patients was 0.76 [95%CI, 0.66-0.92] g/kg Body Weight (BW)/d in the experimental group, and 0.74 [0.70-0.80] g/kg BW/d in the validation group. APR was 0.62 [0.51-0.75] g/kg/d at M3 and 0.87 [0.75-0.98] g/kg/d at M12, with no difference between surgical procedures. Spontaneous protein intakes were respectively 0.80 ± 0.05, 0.43 ± 0.03 and 0.71 ± 0.04 g/kg BW/d respectively at M0, M3 and M12.

CONCLUSION

This study demonstrates a temporal change in protein requirement after bariatric surgery whatever the type of surgery. Spontaneous protein intakes following bariatric surgery does not cover protein requirements for most patients, suggesting that specific dietary protein recommandations have to be adapted in obese patients with bariatric surgery.

TRIAL REGISTRATION

Clinicaltrials.gov Identifier: NCT01249326.

The Relationship Between Energy Intake and Weight Loss in Bariatric Patients

INTRODUCTION

There is a huge variation in weight loss outcomes between bariatric patients, possibly due to differences in caloric intake and changes in the amount physical activity. However, the association between the change in energy intake and weight loss has not yet been the subject of an extensive investigation.

OBJECTIVE

To explore the relationship between total energy intake and % total body weight loss (%TBWL) over a period of 4 years post-surgery.

METHODS

Of the 466 patients who were asked to participate, a total 135 patients were included in this study. They all underwent bariatric surgery, 54 with primary Roux-en-Y Gastric Bypass, 43 redo Roux-en-Y gastric bypass after laparoscopic gastric banding and 38 laparoscopic sleeve gastrectomy. Pre- and post-operative dietary intake and physical activity were collected for both a weekday and a weekend day. The main analysis was performed using multiple regression analyses and was adjusted for age at surgery, BMI at baseline, obstructive sleep apnoea syndrome, type of eating behaviour, change in physical activity and protein intake (g/kg body weight).

RESULTS

%TBWL over time, post-operative energy intake and change in physical activity did not differ between the different procedure groups (p = 0.312, p = 0.988 and p = 0.050, respectively). Change in energy intake did differ between different procedure groups (p = 0.031) and linear regression showed that this was related to total body weight loss for the fully adjusted model (β = - 0.004, p = 0.014).

CONCLUSION

This study showed a higher decrease in energy intake to be related with a higher %TBWL.

Changes in Cardiorespiratory Fitness After Gastric Bypass: Relations with Accelerometry-Assessed Physical Activity

BACKGROUND

Exercise training optimizes cardiorespiratory fitness (CRF) after bariatric surgery, but the effect of spontaneous physical activity is not well known. This study aimed to objectively quantify changes in CRF and habitual physical activity 6 months after bariatric surgery and to examine whether change in CRF was related to change in physical activity.

METHODS

Secondary analyses were performed on data from women who underwent Roux-en-Y gastric bypass (RYGB) between 2010 and 2014. Measurements were performed before and 6 months after RYGB and included V̇O₂peak (graded maximal exercise test on a cycle ergometer), habitual physical activity (Actigraph GT3x accelerometer worn during 7 days), and body composition (DXA absorptiometry). Changes after RYGB were analyzed using Wilcoxon signed-rank test. Relations between change in CRF and change in physical activity were analyzed with Spearman correlations adjusted on age and preoperative BMI.

RESULTS

Forty-five women (median [P₂₅-P₇₅] age, 43.0 [38.0-51.0] year; BMI, 42.6 [40.0-45.5] kg/m²) were included. Mean (SD) weight loss 6 months after RYGB was - 27.5 (7.9) kg (P < 0.001). Absolute V̇O₂peak decreased by 0.35 (0.50) L/min (P < 0.001) and relative V̇O₂peak tended to increase by 1.7 (5.3) mL/kg/min (P = 0.06), both with large inter-individual variability. Based on objective accelerometry data, daily steps and moderate-to-vigorous physical activity increased by 1275 (3164) steps/day and 7.6 (19.3) min/day, respectively (both P < 0.05). Change in absolute V̇O₂peak was positively related to change in moderate-to-vigorous physical activity (r = 0.35; P = 0.03).

CONCLUSIONS

The decrease in absolute CRF observed 6 months after RYGB might be prevented by increasing habitual physical activity.

TRIAL REGISTRATION

clinicaltrials.gov identifier: NCT01113996.

Changes in fat-free mass and muscle mass at 6 and 12 months after biliopancreatic diversion with duodenal switch surgery

BACKGROUND

Bariatric surgery is associated with concomitant loss in both fat and muscle masses. Literature on muscle composition/quality after bariatric surgery is limited.

OBJECTIVES

To measure and compare the changes in fat-free mass with the changes in muscle composition after biliopancreatic diversion with duodenal switch surgery (BPD/DS).

SETTING

Bariatric surgery is associated with concomitant loss in both fat and muscle masses. Literature on muscle composition/quality after bariatric surgery is limited.

METHODS

Forty patients underwent BPD/DS and 22 patients are considered as controls. Bioelectrical impedance analysis (body composition) and computed tomography scan at the midthigh and abdominal levels (muscle composition) were performed at baseline, 6, and 12 months.

RESULTS

At 6 and 12 months, the BPD/DS group displayed significant reduction in weight (12 months: -46.6 ± 13.5 kg) and fat-free mass (12 months: -8.2 ± 4.4 kg; both P < .001). A significant reduction in abdominal (-15 ± 8%, P < .001) and midthigh muscle areas (-18 ± 7%, P < .001) was observed during the first postoperative 6 months, followed by a plateau after 6 months (abdominal: -1 ± 5%, midthigh: -1 ± 4%, both P > .05). At 6 months, both midthigh fat-infiltrated muscle (-22 ± 10%, P < .001) and normal-density muscle (-16 ± 9%, P < .001) areas decreased. Further reduction at 12 months was only observed in the fat-infiltrated muscle (-11 ± 8%, P < .001) in comparison with an increase in the normal-density muscle area (5 ± 8%, P = .001). There was no significant change for the control group.

CONCLUSIONS

Reduction in muscle, assessed with computed tomography scans, occurs mostly during the first 6 months postoperatively after BPD/DS. Focus on muscle quantity as well as quality, using precise imaging methods, instead of quantifying total body lean mass, is likely to provide better assessment in body content modulation after BPD/DS.

Oxyntomodulin and Glicentin May Predict the Effect of Bariatric Surgery on Food Preferences and Weight Loss

BACKGROUND

Alterations in several gastrointestinal hormones are implicated in the postoperative suppression of food intake leading to weight loss after Roux-en-Y gastric bypass (RYGB) and sleeve gastrectomy (SG). The aim was to evaluate changes in responses of gastrointestinal hormones after RYGB and SG and the associations of these changes with weight loss, energy intake, and food preferences.

METHODS

Forty-two subjects with severe obesity were included (32 RYGB; 10 SG). Postprandial responses of glicentin, oxyntomodulin, glucagon-like peptide-1 (GLP-1), peptide YY (PYY), and ghrelin were measured before and 6 months after surgery. Energy intake and energy density were assessed before and 6 months after surgery using a buffet meal test and weight loss was assessed 18 months after surgery.

RESULTS

Postprandial concentrations of glicentin, oxyntomodulin, GLP-1, and ghrelin differed between RYGB and SG (all P ≤ .02). Enhanced responses of glicentin and oxyntomodulin predicted a greater weight loss (both P < .01) and were associated with a larger decrease in energy density (P ≤ .04). No associations were found for GLP-1, PYY, and ghrelin, and changes were not associated with changes in energy intake. When combing all hormones, 60%, 19%, and 33% of the variations in weight loss, energy intake, and energy density, respectively, could be explained.

CONCLUSION

Postprandial responses of gastrointestinal hormones differed between RYGB and SG. Enhanced responses of glicentin and oxyntomodulin predicted a better weight loss and were associated with a decreased preference for energy-dense foods. Replication of these results could imply an opportunity to identify patients in need of additional support after surgical treatments of obesity.

Comparison of Energy and Food Intake Between Gastric Bypass and Sleeve Gastrectomy: a Meta-analysis and Systematic Review

AbstractObesity is a developed nutritional problem, and today, surgery is one of the approaches to cure it. A good understanding of the variations in food intake will be beneficial for sustaining long-term weight loss post-surgery and for improving nutrition care strategies. The purpose of this review was the comparison of the impact of two methods of gastric bypass (GBP) and sleeve gastrectomy (SG) on dietary intake. Databases of PubMed, Embase, Scopus, Google Scholar, and Web of science were used for the literature search up to June 2018. We concluded the studies that measured mean daily energy intake and the percent of macronutrients from total calorie intake of before and after GBP and SG. A total of 18 studies were finally included in the meta-analysis for the effect of bariatric surgery on food intake. Bariatric surgery significantly decreased energy intake by 1050.04 kcal/day (p < 0.001) compared with the baseline values of energy intake. The pooled effect of bariatric surgery on protein intake was 0.82 g/day (p = 0.004) compared with the baseline values. The pooled analysis found no significant impact of bariatric surgery on carbohydrate intake (WMD = 0.56 g/day; p = 0.40) compared with the baseline values. The pooled estimate of effect for bariatric surgery on fat intake was - 1.34 g/day (p = 0.006). This study demonstrates that bariatric surgery might be effective on energy and fat intake; however, there was no effect on carbohydrate intake.

Impact of dietary patterns according to NOVA food groups: 2 y after Roux-en-Y gastric bypass surgery

INTRODUCTION

Appropriate eating habits are crucial for sustained weight loss after bariatric surgery. A qualitative analysis of food consumption in the late postoperative period of bariatric surgery is thus advisable, even more so considering the increasing consumption of obesity-impacting ultra-processed foods.

OBJECTIVE

This study aimed to analyze the contribution of unprocessed, processed, and ultra-processed foods 2 y after Roux-en-Y gastric bypass (RYGB).

METHODS

This was a prospective study performed with 32 patients undergoing RYGB. Anthropometric and food intake data were analyzed. A food intake evaluation was conducted with a focus on quantitative and qualitative analyses. The latter was performed by categorizing food according to the NOVA classification.

RESULTS

There was a reduction in body mass, representing an excess weight loss of 83.80 ± 24.50% at 24 months postoperatively; and a reduction in calorie intake, macronutrients, fiber, and sodium after surgery. Regarding the qualitative analysis, 6 months after RYGB the calorie intake from processed and ultra-processed food decreased from 1398.47 ± 623.82 kcal to 471.80 ± 48.94 kcal (P < 0.05). However, between 6 and 24 months postoperatively there was an increase in 60.04% of the calorie consumption of these type of food (P < 0.01). The most important finding was that the consumption of processed and ultra-processed food exceeded 50% of the total calorie intake of the diet in all periods analyzed.

CONCLUSIONS

RYGB promotes quick results in weight loss and a reduction of food intake, but the quality of food may affect long-term prognosis and deserves attention in the population studied. These results highlight the importance of dietary counseling aimed at guiding better food choices, in the interest of promoting sustained weight loss after bariatric surgery.

Toward a Medical Gastric Bypass: Chronic Feeding Studies With Liraglutide + PYY3-36 Combination Therapy in Diet-Induced Obese Rats

BACKGROUND

Combination therapies of anorectic gut hormones partially mimic the beneficial effects of bariatric surgery. Thus far, the effects of a combined chronic systemic administration of Glucagon-like peptide-1 (GLP-1) and peptide tyrosine tyrosine 3-36 (PYY_3-36) have not been directly compared to Roux-en-Y gastric bypass (RYGB) in a standardized experimental setting.

METHODS

High-fat diet (HFD)-induced obese male Wistar rats were randomized into six treatment groups: (1) RYGB, (2) sham-operation (shams), (3) liraglutide, (4) PYY_3-36, (5) PYY_3-36+liraglutide (6), saline. Animals were kept on a free choice high- and low-fat diet. Food intake, preference, and body weight were measured daily for 4 weeks. Open field (OP) and elevated plus maze (EPM) tests were performed.

RESULTS

RYGB reduced food intake and achieved sustained weight loss. Combined PYY_3-36+liraglutide treatment led to similar and plateaued weight loss compared to RYGB. Combined PYY_3-36+liraglutide treatment was superior to PYY_3-36 (p ≤ 0.0001) and liraglutide (p ≤ 0.05 or p ≤ 0.01) mono-therapy. PYY_3-36+liraglutide treatment and RYGB also reduced overall food intake and (less pronounced) high-fat preference compared to controls. The animals showed no signs of abnormal behavior in OF or EPM.

CONCLUSIONS

Liraglutide and PYY_3-36 combination therapy vastly mimics reduced food intake, food choice and weight reducing benefits of RYGB.

Effects of Roux-en-Y Gastric Bypass and Sleeve Gastrectomy on Food Preferences and Potential Mechanisms Involved

PURPOSE OF REVIEW

Bariatric surgery leads to a substantial decrease in energy intake. It is unclear whether this decrease in energy intake is simply due to eating smaller portions of the same food items or a shift in food preference towards less energy-dense foods. This review evaluates the existing literature on changes in food preferences after bariatric surgery and the potential mechanisms involved.

RECENT FINDINGS

Changes in food preferences have been reported; however, the evidence is mainly based on indirect measurements, such as self-reporting. When changes in food preferences are directly assessed, results contradict previous findings, indicating that results based on self-reporting must be interpreted with caution as they do not necessarily reflect actual behaviour. However, it seems that there could be inter-individual differences in the response to surgery. Future studies investigating changes in food preferences should not only focus on direct measured of behaviour but should also consider the heterogeneity of the response after bariatric surgery.

Most of qualitative dietary changes observed one year post-bariatric surgery can be achieved with a preoperative dietary intervention

BACKGROUND AND OBJECTIVES

Bariatric surgery (BS) leads to several changes in nutritional habits that can be attributed to different mechanisms. Some of these changes could be achievable with a preoperative nutritional intervention. The objective was to evaluate dietary modifications during the preoperative and postoperative periods of BS.

METHODS

Prospective observational study of patients who underwent BS between 2010 and 2014 at the Hospital del Mar; 60 consecutive patients were included. Food consumption was measured by a validated food-frequency questionnaire at inclusion in the bariatric surgery program, after preoperative nutritional intervention, and one year after surgery. Generalized estimating equation models were used to assess differences in food group intake during follow up.

RESULTS

Energy intake significantly decreased from inclusion to 1 year of surgery (p=0.003). After the preoperative intervention and prior to surgery, there was an increase in intake of nuts, vegetables, poultry and rabbit, fruit, fish and skimmed milk products and a decrease in bread, soft drinks and pastry. At one year post-surgery, a continued decrease in the consumption of bread and soft drinks and an increase in nuts was observed (linear non-quadratic trend). Consumption of fruit, pastry, fish and skimmed milk products remained stable showing a linear and quadratic trend. Vegetables and poultry and rabbit increased in the preoperative period and decreased after surgery, showing a quadratic but not linear trend.

CONCLUSIONS

a preoperative nutritional intervention in morbidly obese patients can associate favorable dietary changes that are mostly maintained one year after bariatric surgery.

Meta-analysis of the effect of bariatric surgery on physical activity

BACKGROUND

Obesity leads to impairment of physical activity as measured by an inability to perform activities of daily living. Literature on the effect of bariatric surgery on physical activity is conflicting.

OBJECTIVE

The aim of this study was to perform a meta-analysis of the effect of bariatric surgery on physical activity from studies employing objective measurement and self-reporting of physical activity before and after bariatric surgery.

METHODS

Bibliographic databases were searched systematically for relevant literature until December 31, 2018. Studies employing objective and self-reported measurement of physical activity were included. Study quality was assessed using Risk of Bias in Nonrandomized Studies - of Interventions tool. Meta-analysis was performed using random effects model and presented as standardized mean difference (SMD) with 95% confidence intervals (CI).

RESULTS

Twenty studies identified 5886 patients suitable for the analysis. Physical activity showed significant improvement at 0-6 months (SMD: .50; 95% CI: .25-.76; P = .0001), >6-12 months (SMD: .58; 95% CI: .26-.91; P = .0004), and >12-36 months (SMD: .82; 95% CI: .27-1.36; P = .004) after bariatric surgery. Self-reported assessment after bariatric surgery showed significant improvement at 0-6 months (SMD: .65; 95% CI: .29-1.01; P = .0004), >6 to 12 months (SMD: .53; 95% CI: .18-.88; P = .003), and >12-36 months (SMD: .51; 95% CI: .46-.55; P < .00001). Objective assessment after bariatric surgery did not show improvement at 0-6 months (SMD: .31; 95%CI:-.05-.66; P = .09), but showed significant improvement at >6-12 months (SMD: .85; 95% CI:-.07-1.62; P = .03), and >12-36 months (SMD: 1.99; 95% CI: 1.13-2.86; P < .00001) after bariatric surgery.

CONCLUSIONS

Bariatric surgery improves physical activity significantly in a population with obesity up to 3 years after surgery. Objective measurement of physical activity does not show significant improvement within 6 months of bariatric surgery but begins to improve at >6 months. Self-reported measurement of physical activity begins to show improvement within 6 months of a bariatric procedure.

Perception of Hunger/Satiety and Nutrient Intake in Women Who Regain Weight in the Postoperative Period After Bariatric Surgery

OBJECTIVE

To investigate the perception of hunger and satiety and its association with nutrient intake in women who regain weight in the postoperative period after bariatric surgery.

METHODS

Cross-sectional study of adult women divided into three groups: weight regain (n = 20), stable weight (n = 20) (both at least 24 months after Roux-en-Y gastric bypass surgery), and non-operated obesity (n = 20). A visual analogue scale measured hunger/satiety perception while fasting, immediately after finishing a test meal, and 180 min after finishing the test meal. The incremental area above or under the curve was calculated. Food intake was analyzed by 3 days of food recall and adjusted for intraindividual variation. To make between-group comparisons, Mann-Whitney, ANOVA, Kruskal-Wallis, and independent-samples T tests and Pearson's correlation were used.

RESULTS

There were no between-group differences in incremental areas of hunger/satiety, but protein intake was significantly lower among patients who regained weight compared with those who had stable body weight (0.99 ± 0.23 g/kg body weight vs. 1.17 ± 0.21 g/kg body weight, p = 0.047). In the group that regained weight, satiety was correlated positively with usual dietary protein density (r = 0.541; p = 0.017) and negatively with usual carbohydrate intake (r = - 0.663; p = 0.002).

CONCLUSION

Women who regained weight presented similar perceptions of hunger/satiety to those of patients without weight regain and with non-operated obesity. In patients who regained weight postoperatively, satiety perception was correlated positively with usual dietary protein density and inversely with usual carbohydrate intake.

Functional and systemic effects of whole body electrical stimulation post bariatric surgery: study protocol for a randomized controlled trial

Background

Obesity represents a major public health problem and is the fifth leading risk factor for mortality. Morbid obesity is associated with chronic systemic inflammation which increases the risk of comorbidities. Bariatric surgery (BS) is considered an effective intervention for obese patients. However, BS is associated with dietary restriction, potentially limiting physical activity. Whole-body neuromuscular electrical stimulation (WBS) could represent an innovative option for the rehabilitation of BS patients, especially during the early postoperative phase when other conventional techniques are contraindicated. WBS is a safe and effective tool to combat sarcopenia and metabolic risk as well as increasing muscle mass, producing greater glucose uptake, and reducing the proinflammatory state. Therefore, the objective of this study is to evaluate the effects of WBS on body composition, functional capacity, muscle strength and endurance, insulin resistance, and pro- and anti-inflammatory circulating markers in obese patients undergoing BS.

Methods/design

The present study is a randomized, double-blind, placebo-controlled, parallel groups clinical trial approved by the Ethics Committee of our Institution. Thirty-six volunteers (body mass index (BMI) > 35 kg/m²) between 18 and 45 years of age will be randomized to the WBS group (WBSG) or control (Sham) group (ShamG) after being submitted to BS. Preoperative assessments will include maximal and submaximal exercise testing, body composition, blood inflammatory markers, and quadriceps strength and endurance. The second day after discharge, body composition will be evaluated and a 6-min walk test (6MWT) will be performed. The WBS or Sham protocol will consist of 30 daily sessions for 6 consecutive weeks. Afterwards, the same assessments that were performed in the preoperative period will be repeated.

Discussion

Considering the important role of WBS in skeletal muscle conditioning and its value as an aid in exercise performance, the proposed study will investigate this technique as a tool to promote early rehabilitation in these patients, and as a strategy to enhance exercise capacity, weight loss, and peripheral muscle strength with positive systemic effects. The present study is still ongoing, and data will be published after its conclusion.

Trial registration

REBEC, RBR-99qw5h. Registered on 20 February 2015.

Electronic supplementary material

The online version of this article (10.1186/s13063-018-2844-8) contains supplementary material, which is available to authorized users.