Changes in Body Composition, Dietary Intake, and Substrate Oxidation in Patients Underwent Laparoscopic Roux-en-Y Gastric Bypass and Laparoscopic Sleeve Gastrectomy: a Comparative Prospective Study

IMPACT OF SIMULATED CALORIC REDUCTION ON NUTRIENT ADEQUACY AMONG US ADULTS WITH OVERWEIGHT OR OBESITY (NHANES 2015-2018)

BACKGROUND

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

OBJECTIVE

This study models the impact of simulated caloric reduction on nutrient adequacy among US 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 pro-rating 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 non-overlapping confidence intervals of the means (97.5th percentile confidence intervals were used to approximate p<0.05).

RESULTS

There were meaningful 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, B6, 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 B6 and zinc, and 75-91% of the population had intakes below the EAR for vitamin A, calcium and magnesium (versus 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.

Effect of laparoscopic sleeve gastrectomy versus laparoscopic Roux-en-Y gastric bypass on body composition

BACKGROUND

There is limited data with respect to body composition changes for laparoscopic sleeve gastrectomy (SG) and laparoscopic Roux-en-Y gastric bypass (RYGB). The objective of this study was to analyse changes in body composition between these two procedures during the first year after bariatric surgery.

METHODS

A prospective study was performed in patients undergoing bariatric surgery at two tertiary hospitals between 2017 and 2023. Body composition was assessed with dual-energy x-ray absorptiometry immediately before surgery, and at 1-, 6-, 12-, 18- and 24-months post-operatively, with a subgroup analysis performed for patients who undertook a scan at 18- and 24-months. Total weight loss (TWL), body mass index (BMI), fat mass (FM), lean body mass (LBM) and bone mineral content (BMC) parameters were compared between SG and RYGB.

RESULTS

Forty-five patients were included in this series (SG n = 30, RYGB n = 15). There was a significant reduction in mean %TWL of 26.94 ± 8.86% and mean BMI of 11.12 ± 3.70 kg/m2 over 12-months. LBM accounted for 17.8% of TWL over 12-months, SG and RYGB did not differ in terms of loss of FM or LBM. For both procedures, the loss of LBM appeared to plateau at 6-months post-operatively. The only statistically significant finding between the two procedures was that RYGB resulted in an additional 0.06 kg loss compared with SG.

CONCLUSION

SG and RYGB have been shown to have comparable weight loss and body composition changes in the short-to-medium term following surgery. LBM reduction was most significant in the early post-operative period across the entire cohort.

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.

Short-Term Changes in Weight, Body Composition, and Metabolic Biomarkers After Laparoscopic Sleeve Gastrectomy in Patients with Obesity: A Comparative Prospective Study

PURPOSE

To investigate the changes in weight, body composition, and metabolic biomarkers in patients with obesity after laparoscopic sleeve gastrectomy (LSG) and compare those changes between patients with and without metabolic syndrome (MS).

MATERIALS AND METHODS

This retrospective longitudinal study included 76 patients who underwent LSG, among whom 32 had complete 1-year postoperative body composition and metabolic biomarkers. Body composition was measured by quantitative CT. Weight changes were compared between the MS and non-MS groups at 1-, 3-, 6-, and 12-month post-LSG in all patients; changes in body compositions and metabolic biomarkers from one day pre-LSG to 12-month post-LSG were also compared in those 32 patients.

RESULTS

MS occurred in 46% (35/76) of all patients and 44% (14/32) of patients with complete follow-up data. Excess weight loss was lower in the MS group than that in the non-MS group at 1-, 3-, 6-, and 12-month post-LSG; the 12-month difference was significant (MS vs. non-MS: 0.91 ± 0.22 vs. 1.07 ± 0.42, P = 0.04). The greatest rate of visceral fat area (VFA) change occurred 12-month post-LSG in both the non-MS [0.62(0.55,0.7)] and MS [0.6(0.51,0.63)] groups. The most significant reduction in ectopic fat occurred in liver fat (LF) [non-MS, 0.45(0.22,0.58); MS, 0.39(0.23,0.58)].

CONCLUSION

LGS significantly improves weight, body composition, and metabolic biomarkers in populations with obesity, regardless of whether they have MS. Among the body composition, VFA and LF were the most significantly improved body composition measurements.

The effects of protein intake higher than the recommended value on body composition changes after bariatric surgery: A meta-analysis of randomized controlled trials

BACKGROUND & AIMS

There is a lack of a meta-analysis to comprehensively assess the effectiveness of higher protein intake in addition to the recommended value on body composition post-bariatric surgery. We aimed to perform a meta-analysis of randomized controlled trials to determine the effects of protein intake higher than the recommended value on body composition changes after bariatric surgery.

METHODS

Electronic databases, including Scopus, PubMed/Medline, and Web of Sciences, were searched until July 2023. Studies that assessed the effect of protein intake higher than the recommended value on postoperative body composition, i.e., weight, body mass index (BMI), fat mass (FM), fat-free mass (FFM), percent fat mass (PFM), and percent total weight loss (%TWL), were eligible. For each outcome, the mean and standard deviation (for changes from baseline) were used to synthesize the data.

RESULTS

Eight trials were included in the current study. The results of the meta-analysis indicated protein intake higher than the recommended value after bariatric surgery led to more weight loss by 4.95 kg (95 % CI: -9.41 to -0.49) and FM loss by 7.64 kg (95 % CI: -14.01 to -1.28) compared with the control group. However, it had no significant effects on postoperative changes in BMI, FFM, PFM, or %TWL. There were no significant differences in body composition between protein sources obtained from diet and supplementation. When data was stratified based on the amount of added protein, we found a significant reduction in weight (MD: -7.80 kg; 95 % CI: -14.50 to -1.10) in patients who consumed protein ≥ 40 g/d in addition to the recommended value. Besides, protein intake higher than the recommended value declined FFM loss in patients who underwent laparoscopic sleeve gastrectomy (LSG) (MD: 6.52 kg; 95 % CI: 0.99 to 12.02).

CONCLUSION

The results of the current meta-analysis indicated that protein intake higher than the recommended value might cause greater weight and FM loss after bariatric surgery than a normal protein diet. However, our findings did not support the role of additional protein in the preservation of FFM, except in patients with LSG.

Distinctive patterns of sulfide- and butyrate-metabolizing bacteria after bariatric surgery: potential implications for colorectal cancer risk

Despite improved cardiometabolic outcomes following bariatric surgery, its long-term impact on colorectal cancer (CRC) risk remains uncertain. In parallel, the influence of bariatric surgery on the host microbiome and relationships with disease outcomes is beginning to be appreciated. Therefore, we investigated the impact of Roux-en-Y gastric bypass (RYGB) and vertical sleeve gastrectomy (VSG) on the patterns of sulfide-reducing and butyrate-producing bacteria, which are hypothesized to modulate CRC risk after bariatric surgery. In this single-center, cross-sectional study, we included 15 pre-surgery subjects with severe obesity and patients who are at a median (range) of 25.6 (9.9-46.5) months after RYGB (n = 16) or VSG (n = 10). The DNA abundance of fecal bacteria and enzymes involved in butyrate and sulfide metabolism were identified using metagenomic sequencing. Differences between pre-surgery and post-RYGB or post-VSG cohorts were quantified using the linear discriminant analysis (LDA) effect size (LEfSe) method. Our sample was predominantly female (87%) with a median (range) age of 46 (23-71) years. Post-RYGB and post-VSG patients had a higher DNA abundance of fecal sulfide-reducing bacteria than pre-surgery controls (LDA = 1.3-4.4, p < .05). The most significant enrichments were for fecal E. coli, Acidaminococcus and A. finegoldii after RYGB, and for A. finegoldii, S. vestibularis, V. parvula after VSG. As for butyrate-producing bacteria, R. faecis was more abundant, whereas B. dentium and A. hardus were lower post-RYGB vs. pre-surgery. B. dentium was also lower in post-VSG vs. pre-surgery. Consistent with these findings, our analysis showed a greater enrichment of sulfide-reducing enzymes after bariatric surgery, especially RYGB, vs. pre-surgery. The DNA abundance of butyrate-producing enzymes was lower post-RYGB. In conclusion, the two most used bariatric surgeries, RYGB and VSG, are associated with microbiome patterns that are potentially implicated in CRC risk. Future studies are needed to validate and understand the impact of these microbiome changes on CRC risk after bariatric surgery.

The Risk of Colorectal Polyps after Weight Loss Therapy Versus Obesity: A Propensity-Matched Nationwide Cohort Study

BACKGROUND

A fundamental understanding of the impact of bariatric surgery (BRS) on mechanisms of colorectal carcinogenesis is limited. For instance, studies report a reduced risk of colorectal cancer in females but not in males after BRS. We examined whether this sex-specific difference existed at the earlier polyp development stage.

METHODS

This retrospective cohort study included 281,417 adults from the 2012-2020 MarketScan database. We compared polyps rates on colonoscopy in four groups: post- vs. pre-BRS (treatment) to post- vs. pre-severe obesity (SO) diagnosis (control). We focused our main analysis on a propensity-matched sample that yielded a balanced distribution of covariates in our four groups (n = 9680 adults, 21.9% males). We also adjusted for important covariates.

RESULTS

Metabolic syndrome parameters improved after bariatric surgery and worsened after severe obesity diagnosis (p < 0.05). The rate of polyps was 46.7% at a median of 0.5 years pre-BRS and 47.9% at a median of 0.6 years pre-SO diagnosis. The polyps rate was 45.4% at a median (range) of 3.2 (1.0-8.5) years post-BRS. Conversely, 53.8% of adults had polyps at 3.0 (1.0-8.6) years post-SO. There was no change in the risk of colorectal polyps in males or females post- vs. pre-BRS. However, the risk of polyps was higher in males (OR = 1.32, 95% CI: 1.02-1.70) and females (OR = 1.29, 95% CI: 1.13-1.47) post- vs. pre-SO. When compared to the control group (SO), the odds ratios for colorectal polyps were lower for males and females after bariatric surgery (OR = 0.63, 95% CI: 0.44-0.90, and OR = 0.79, 95% CI: 0.66-0.96, respectively).

CONCLUSIONS

Obesity is associated with an increased risk of colorectal polyps, an effect that is ameliorated after bariatric surgery. These data are relevant for studies investigating colorectal carcinogenesis mechanisms.

Changes in Lean Tissue Mass, Fat Mass, Biological Parameters and Resting Energy Expenditure over 24 Months Following Sleeve Gastrectomy

Sleeve gastrectomy (SG) induces weight loss but its effects on body composition (BC) are less well known. The aims of this longitudinal study were to analyse the BC changes from the acute phase up to weight stabilization following SG. Variations in the biological parameters related to glucose, lipids, inflammation, and resting energy expenditure (REE) were concomitantly analysed. Fat mass (FM), lean tissue mass (LTM), and visceral adipose tissue (VAT) were determined by dual-energy X-ray absorptiometry in 83 obese patients (75.9% women) before SG and 1, 12 and 24 months later. After 1 month, LTM and FM losses were comparable, whereas at 12 months the loss of FM exceeded that of LTM. Over this period, VAT also decreased significantly, biological parameters became normalized, and REE was reduced. For most of the BC, biological and metabolic parameters, no substantial variation was demonstrated beyond 12 months. In summary, SG induced a modification in BC changes during the first 12 months following SG. Although the significant LTM loss was not associated with an increase in sarcopenia prevalence, the preservation of LTM might have limited the reduction in REE, which is a longer-term weight-regain criterion.

Assessment of the Clinical Condition and Way of Patients' Nutrition before and after Laparoscopic Sleeve Gastrectomy

One of the most commonly performed bariatric procedures is the laparoscopic sleeve gastrectomy (LSG). It is highly effective in reducing body weight, but it carries the risk of developing nutritional deficiencies and their consequences. The aim of the study was to determine the clinical condition of obese patients after LSG in terms of nutritional status, metabolic disorders, and way of nutrition. Thirty participants (15 women and 15 men) took part in the study. A statistically significant reduction in the total body fat mass (women by 37.5% p < 0.05, men by 37.06% p < 0.05) and total fat free mass (women by 10% p < 0,05, men by 12.5% p < 0.05) was demonstrated 6 months after LSG. Moreover, insufficient protein intake has been shown in over 73% of women and 40% of men. Before and 6 months after LSG, insufficient intake of calcium, magnesium, potassium, folate, vitamin D, and iron was observed. Six months after the LSG, significant decreases of fasting glucose (p < 0.05), insulin (p < 0.05), TG (p < 0.05), and AST (p < 0.05) concentrations, were observed in both groups. Optimization of nutrition in order to prevent nutritional deficiencies and their complications is a key element of the therapy of obese patients treated surgically.

Dietary advice for patients with bowel-related conditions and malabsorption

PURPOSE

To explain the pathophysiology of kidney stone formation and appropriate dietary recommendations in inflammatory bowel diseases (IBD) such as ulcerative colitis (UC) and Crohn's disease (CD) and after bariatric surgery, focusing on the current literature.

METHODS

A narrative review methodology was performed. A literature search was conducted using PubMed, MEDLINE, and Google Scholar. Studies on the relationship between IBD or bariatric surgery and the risk of kidney stone formation were included.

RESULTS

Dietary composition has a critical role in urinary stone formation. Nutritional factors such as fluid intake, dietary protein, carbohydrates, oxalate, and calcium contribute to the risk of stone formation. Bowel-related malabsorptive conditions (IBD, after bariatric surgery, etc.) are associated with an increased risk of kidney stone formation due to metabolic and physiological changes such as hyperoxaluria, hypocitraturia, and decreased fluid intake or absorption. While the risk is lower in restrictive bariatric surgeries, the risk of kidney stone formation increases, especially after malabsorptive procedures. Dietary recommendations for these patients could profit alleviate urinary changes and reduce the risk of kidney stones.

CONCLUSION

Bowel-related malabsorptive conditions such as IBD and bariatric surgery are associated with an increased risk of kidney stones. Appropriate dietary recommendations can improve urinary metabolic changes and reduce kidney stone formation and the possibility of stone-related surgery.

Comparing Effects of Bariatric Surgery on Body Composition Changes in Metabolically Healthy and Metabolically Unhealthy Severely Obese Patients: Tehran Obesity Treatment Study (TOTS)

BACKGROUND

Among two popular obesity phenotypes, metabolically healthy severely obese (MHSO) and metabolically unhealthy severely obese (MUSO), it is important to clarify whether or not those with MHSO phenotype would benefit from bariatric surgery in terms of an improvement in body composition parameters.

METHODS

A prospective cohort was conducted on a total of 4028 participants (1404 MHSO and 2624 MUSO) who underwent bariatric surgery; MHSO was defined as having abnormalities in none or one of these four parameters: systolic blood pressure and/or diastolic blood pressure, triglycerides, fasting plasma glucose, and high-density lipoprotein. Otherwise, the definition of MUSO was met. Body composition analysis was performed at the baseline and 6-, 12-, 24-, and 36-month post-surgery using bioelectrical impedance analyzer.

RESULTS

Both phenotypes showed a significant decrease in fat mass (FM) and fat-free mass (FFM) and a significant increase in EWL% and TWL% (P_trend < 0.05). FFM, FM%, and excess weight loss (EWL%) were significantly different between the two phenotypes (P_between < 0.05) during the follow-up. Multivariate linear regression demonstrated that compared to MUSO patients, MHSO individuals experienced a greater increase in total weight loss (TWL%) and EWL% at 12- and 24-month and in EWL% at 36-month post-surgery and also a lower decrease in the FFML/WL% after 12 months.

CONCLUSION

Despite a lower decrease of FFML/WL% and a greater increase in TWL and EWL in MHSO phenotype at some time points, there were no clinically significant differences between the study groups in terms of body composition changes throughout the follow-up period.

Phase angle (PhA) in overweight and obesity: evidence of applicability from diagnosis to weight changes in obesity treatment

Phase angle (PhA) is a recently proposed marker of nutritional status in many clinical conditions. Its use in patients with obesity presents different critical concerns due to the higher variability of the two measured parameters (resistance, R, and reactance, Xc) that contribute to the determination of PhA. Controversial is the relation between PhA and BMI that might vary with graded levels of obesity due to the variation in fat and free fat mass. Obesity is frequently associated with metabolic, hepatic, cardiovascular and kidney diseases that introduce variations in PhA values, in relation to multimorbidity and severity degree of these diseases. It is reported that the improvement of clinical condition is associated with a positive change in PhA. Also, the treatment of obesity with weight loss might confirm this effect, but with different responses in relation to the type and duration of the intervention applied. In fact, the effect appears not only related to the percentage of weight loss but also the possible loss of free fat mass and the nutritional, metabolic and structural modifications that might follow each therapeutic approach to decrease body weight. We can conclude that the PhA could be used as marker of health status in patients with obesity supporting an appropriate weight loss intervention to monitor efficacy and fat free mass preservation.

Resolution of diabetes, gastrointestinal symptoms, and self-reported dietary intake after gastric bypass vs sleeve gastrectomy – a randomized study

BACKGROUND

There is a lack of randomized studies examining diabetes remission and dietary intake between patients undergoing Roux-en-Y gastric bypass (RYGB) versus sleeve gastrectomy (SG).

OBJECTIVE

To examine longitudinal differences in diabetes resolution, dietary intake, and gastrointestinal (GI) symptoms in patients with obesity and type 2 diabetes (T2D) randomized to either RYGB or SG and according to remission of T2D.

SETTING

Four hospitals in Sweden, 2 of which are university hospitals.

METHODS

Dietary intake and GI symptoms were calculated from questionnaires and morphometric differences between surgical methods and T2D remission were compared using the Student t test, effect size (ES) for parametric parameters, and Mann-Whitney U test for nonparametric parameters.

RESULTS

Five years after RYGB or SG there was no significant difference in the rate of remission of T2D between RYGB and SG (43% versus 20%, P = .176). RYGB (n = 19) patients had greater weight loss than SG patients (n = 14) (26.4 [9.5] versus 13.1 [9.6] kg, P < .001), despite reporting higher daily caloric intake (Δ 669 kcal, P = .059, ES .67) and food weight (Δ 1029 g/d, P = .003, ES 1.11). RYGB patients, compared with SG patients, also ate 1 more fruit per day (P = .023). Pooled data showed no differences between patients with and without T2D remission regarding weight loss, but those in remission drank more nonalcoholic drinks and milk.

CONCLUSIONS

Five years postoperatively, patients randomized to RYGB reported considerably higher food intake compared with SG despite lower body weight. The reason and importance of the higher food intake after RYGB compared with SG needs to be further studied.

A Higher Phase Angle Is Associated with Greater Metabolic Equivalents in Women 1 Year After Bariatric Surgery

BACKGROUND

Phase angle (PhA), proposed as an indicator of the number, integrity, and function of cells and evaluated in some clinical situations, decreases after bariatric surgery (BS). In contrast, higher values are found in physically active or exercising individuals. We therefore evaluated the influence of physical activity on PhA after BS.

METHODS

The PhA and body composition (obtained by bioelectrical impedance analysis), physical activity level (obtained by International Physical Activity Questionnaire), and metabolic equivalents (METs) were evaluated in adult women submitted to BS. The PhA and body composition were evaluated at three time points: before and 6 and 12 months after surgery. Physical activity level and METs were measured at the two postoperative time points.

RESULTS

A reduction in PhA was observed 6 (p < 0.01) and 12 months (p < 0.01) after BS, with no significant difference between time points. A moderate or high physical activity level was found in 81% of the volunteers after 6 months and in 65% after 12 months. METs were reduced after 12 months compared to 6 months. A positive correlation (p < 0.05) was observed between PhA and body cell mass after surgery. There was a significant positive correlation (p < 0.01) between PhA and METs after 12 months.

CONCLUSIONS

Physical activity may attenuate the PhA reduction that occurs after BS, with this parameter reflecting the engagement of these patients in this type of activity.

Short-Term Changes on Body Composition After Sleeve Gastrectomy and One Anastomosis Gastric Bypass

Introduction: Changes in body composition after different bariatric surgeries have been studied extensively, but most of them have emphasized on Roux-en-Y gastric bypass. Only a few studies have assessed the effects of sleeve gastrectomy (SG). Also, the effect of one anastomosis gastric bypass (OAGB) on body composition is not fully apprehended. Furthermore, there is no agreement on how much fat-free mass (FFM) loss is tolerable in weight loss interventions. Therefore, we decided to assess the reduction in fat mass (FM) and FFM at 1, 3, 6, and 12 months after two types of bariatric surgery in a single center. Methods: In the current retrospective cross-sectional study, the patients' hospital records were analyzed. We included patients who had SG or OAGB and a complete 1-year follow-up record. We recorded demographic data as well as weight, body mass index (BMI), FM, and FFM before and at 1, 3, 6, and 12 months after surgery in a predesigned checklist. Results: We analyzed 311 patients (43 males and 268 females) in the SG (N = 192, 61.7%) and OAGB (N = 119, 38.3%) groups. Both the SG and OAGB groups demonstrated a statistically significant reduction in weight, BMI, FM, and FFM indices at 12 months after the intervention (P < .001). Moreover, no statistically significant difference was observed between the SG and OAGB groups regarding the mean of all body composition indices at 3, 6, and 12 months after the intervention. Conclusion: We found that SG and OAGB effectively decreased weight and body composition indices, comprising FM and FFM, with no significant difference between each other.

Body Composition Changes Following Sleeve Gastrectomy Vs. One-Anastomosis Gastric Bypass: Tehran Obesity Treatment Study (TOTS)

PURPOSE

This study aimed to evaluate body composition changes and the determinants of fat-free mass loss (FFML) up to 3 years after sleeve gastrectomy (SG) and one-anastomosis gastric bypass (OAGB).

MATERIALS AND METHODS

A prospective study was conducted on 3864 patients with severe obesity who underwent either SG (2746, 76.1% women, mean age: 39.2 ± 11.6 years, and BMI: 44.3 ± 5.6 kg/m²) or OAGB (1118, 82.2% women, age: 39.9 ± 10.7 years, BMI: 45.6 ± 6.3 kg/m²). Body composition parameters were measured by bioelectrical impedance analysis preoperatively and 1, 3, 6, 9, 12, 18, 24, and 36 months after surgery. Changes in body composition were assessed using the propensity matched generalized estimated equation (GEE) method. The determinants of fat-free mass loss/weight loss (FFML/WL%) were defined using a mixed-model GEE analysis.

RESULTS

Means of FM, FFM, and FFML/WL% decreased significantly in both study groups (P_trend < 0.001). Changes in BMI, EWL%, FM, and FFML/WL% were different between the two groups (P_between < 0.05). The results showed a better FFM preservation and a greater FM loss over time in the OAGB group compared to the SG group (P_interaction < 0.05). FFML during the first 3 months was greater in the SG compared to the OAGB group (P < 0.001). SG surgery, higher preoperative BMI, and female gender were associated with greater FFML/WL%.

CONCLUSION

In the SG compared to the OAGB group, FFML was greater, especially early after the surgery, emphasizing the need for therapeutic interventions such as regular exercise programs and dietary intake modifications.

Bioelectrical impedance (BIA)-derived phase angle in adults with obesity: A systematic review

BACKGROUND & AIMS

Bioimpedance analysis-derived phase angle (PhA), as marker of body cell mass and cell integrity, might be altered in obesity, a condition which is characterized by alterations in muscle structure and function. The aim of this systematic review was to evaluate whether and to which extent PhA varies in individuals/patients with excess body weight focusing on: a) changes in PhA due to obesity; b) changes in PhA after bariatric interventions or training programs.

METHODS

According to PRISMA criteria, a systematic literature search until February 2021 using PubMed, Embase, Scopus, and Web of Science was performed. Selection criteria included studies on patients with obesity without comorbidities other than metabolic diseases.

RESULTS

A total of 278 articles were first identified. After removing duplicates and excluding studies that did not fulfil the inclusion criteria, the full text of the remaining 80 potentially relevant studies was examined to finally retrieve 11 cross-sectional and 10 longitudinal studies. Few studies have shown that PhA is lower in individuals/patients with obesity than in controls. The only study on the matter showed a decrease with age after the fourth decade of life. Four out of five studies reported consistently greater mean values in men than in women. In two studies PhA was lower in patients with severe obesity; in addition, Patients with low PhA had higher BMI and PhA was inversely correlated with fat mass. Longitudinal studies showed that PhA markedly decreased after bariatric surgery and slightly increased after training programs.

CONCLUSIONS

Thus, a relatively low number of studies have evaluated PhA in individuals/patients with obesity with sometimes contradictory and preliminary results. PhA might be useful to evaluate muscle quality in individuals/patients with obesity but further studies are needed to more accurately associate this variable with changes in muscle structure and strength, as well as in metabolic functions.

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.

How Does Fat Mass Change in the First Year After Bariatric Surgery? A Systemic Review and Meta-Analysis

This systematic review and meta-analysis investigated the time-course effect of different type of bariatric surgeries (BS) up to 1 year post-surgery on fat mass (FM) and body fat percentage (BFP) in patients with morbid obesity. We searched PubMed, Scopus, EMBASE, ISI web of science, and Cochrane databases from October 2002 until May 2020 with no restriction in the English language, to find studies examining the effect of BS on FM (kg) and BFP (%) in morbid obese patients. Meta-analysis of 103 studies carried out on data of 18,166 and 14,575 morbid obese patients following BS, showed that BS was associated with a substantial decrease in FM and BFP, respectively, in 1 month (- 8.17 kg [95% CI - 9.07, - 7.27] and - 1.51% [95% CI - 2.56, - 0.46]), 3 months (- 15.75 [95% CI - 17.49, - 14.0] and - 4.90 [95% CI - 5.97, - 3.83]), 6 months (- 22.51 [95% CI - 23.93, - 21.09] and - 8.56% [95% CI - 9.63, - 7.49]), and 12 months (- 29.69 [95% CI - 31.3, - 28.09] and - 13.49% [95% CI - 14.52, - 12.40]) after the surgery. In conclusion, BS was associated with sustained declines in FM and BFP, from 1 to 12 months, with no indication of plateau phase post-surgery post-operatively. The present study emphasizes that post-bariatric care should have more focus on FM loss during 1-year post-surgery to identify the patients at risk for fat loss plateau.

A Comparison of the Effects of Roux-en-Y Gastric Bypass and Sleeve Gastrectomy on Body Mass Composition as Measured by Air Displacement Plethysmography

BACKGROUND

The laparoscopic sleeve gastrectomy (LSG) is now the most commonly performed bariatric surgery in the world. Multiple studies have demonstrated the equivalence between the LSG and Roux-en-Y gastric bypass (RYGB) with regard to weight loss and comorbidity resolution. Few studies have examined the differences in body mass composition change between the two procedures.

METHODS

Sixty-three patients undergoing either LSG or RYGB underwent calculation of total body mass, ideal body mass, lean mass, and fat mass by air displacement plethysmography (BodPod^tm) prior to surgery and at 12 months postoperatively. Calculations of excess body weight, % excess weight loss, change in % fat mass, and change in % lean mass were then performed at each time interval.

RESULTS

Thirty-three patients underwent LSG and 30 patients underwent RYGB. Mean percent excess weight loss in the LSG and RYGB group was 47.2% and 53.4% respectively (p = 0.165, 95% CI - 14.8-2.6). Mean percent change in fat mass for the LSG group and RYGB group was 9.2% and 10.51% respectively (p = 0.249, 95% CI - 0.86-3.2). Mean percent change in lean mass for the LSG group and RYGB group was 9.4% and 10.49% respectively (p = 0.383, 95% CI 2.85-1.13).

CONCLUSION

The LSG and RYGB both impart dramatic meaningful loss in excess body weight. In addition, both the LSG and RYGB impart dramatic reductions in fat mass. However, both procedures induce loss of lean mass and there appears to be no difference between the two procedures in this regard despite their anatomic and physiologic differences.

Recent Advances in Hypertension: Intersection of Metabolic and Blood Pressure Regulatory Circuits in the Central Nervous System

Obesity represents the single greatest ongoing roadblock to improving cardiovascular health. Prolonged obesity is associated with fundamental changes in the integrative control of energy balance, including the development of selective leptin resistance, which is thought to contribute to obesity-associated hypertension, and adaptation of resting metabolic rate (RMR) when excess weight is reduced. Leptin and the melanocortin system within the hypothalamus contribute to the control of both energy balance and blood pressure. While the development of drugs to stimulate RMR and thereby reverse obesity through activation of the melanocortin system has been pursued, most of the resulting compounds simultaneously cause hypertension. Evidence supports the concept that although feeding behaviors, RMR, and blood pressure are controlled through mechanisms that utilize similar molecular mediators, these mechanisms exist in anatomically dissociable networks. New evidence supports a major change in molecular signaling within AgRP (Agouti-related peptide) neurons of the arcuate nucleus of the hypothalamus during prolonged obesity and the existence of multiple distinct subtypes of AgRP neurons that individually contribute to control of feeding, RMR, or blood pressure. Finally, ongoing work by our laboratory and others support a unique role for AT₁ (angiotensin II type 1 receptor) within one specific subtype of AgRP neuron for the control of RMR. We propose that understanding the unique biology of the AT₁-expressing, RMR-controlling subtype of AgRP neurons will help to resolve the selective dysfunctions in RMR control that develop during prolonged obesity and potentially point toward novel druggable antiobesity targets that will not simultaneously cause hypertension.

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.

Roux-en-Y Gastric Bypass and Sleeve Gastrectomy Differently Affect Oxidative Damage Markers and their Correlations with Body Parameters

BACKGROUND

Bariatric surgery improves oxidative damage, but little is known about the differences between Roux-en-Y gastric bypass (RYGB) and sleeve gastrectomy (SG). This study compared changes in lipid and protein oxidative damage markers and their correlations with body parameters of patients before and after RYGB or SG.

METHODS

Body mass index (BMI), bioimpedance parameters, and biochemical parameters including lipid and protein oxidative damage markers were evaluated before and 6 months after surgery. Data were analyzed by t test or Mann-Whitney rank sum test and Spearman's correlation coefficient between oxidative damage and other parameters.

RESULTS

Twenty-five patients were submitted to RYGB and 14 to SG. There was a significant decrease of BMI, fat mass, fat-free mass, phase angle, serum total protein, transthyretin, and C-reactive protein in both groups (p < 0.05). Serum thiobarbituric acid reactive substances (TBARS), advanced oxidation protein products (AOPP), and serum lipids (p < 0.05) were significantly decreased in the RYGB group. TBARS levels were significantly correlated with serum total cholesterol (r = 0.468), LDL (r = 0.439), BMI (r = 0.424), and fat mass (r = 0.40) (p < 0.05). In the SG group, AOPP levels were significantly correlated with serum C-reactive protein (baseline: r = 0.53, 6 months: r = 0.64) (p < 0.05). Alterations in these levels were negatively correlated with changes in BIA parameters [resistance (r = -0.574), reactance (r = -0.736), and phase angle (r = 0.549)] (p < 0.05).

CONCLUSIONS

RYGB seems to be better in attenuating oxidative damage after 6 months. The BMI reduction in the RYGB group suggests a concomitant decrease of lipid oxidative damage. In the SG group, changes in BIA parameters were inversely correlated with protein oxidative damage.

[Body composition assessment before and after weight loss following a Roux-en-Y gastric bypass. Are bioimpedanciometry estimations reliable?]

Introduction

Introduction: in patients with severe and morbid obesity it has been observed that bioimpedance (BIA) assessment generates an underestimation of fat mass (FM) and weight loss as FM after bariatric surgery, overestimating the loss of fat-free mass (FFM) and muscle mass. Objective: to evaluate the reliability of bioelectrical impedance analysis (BIA) to estimate total body water (TBW), fat-free mass (FFM), fat mass (FM), and its changes after 6 months of a Roux-en-Y gastric bypass (RYGBP), in patients with severe and morbid obesity. Methods: thirty-six patients approved for RYGBP were prospectively studied. TBW was measured by deuterium (D), and FM and FFM were calculated. A dual-frequency BIA device (5 and 200 kHz) (Bodystat Dualscan®) was used to estimate FM, FFM, TBW, extracellular water (ECW), intracellular water (ICW), and ECW/ICW ratio. Results: before RYGBP, BIA overestimated TBW by 2.6 ± 4.3 L (p = 0.002) and FFM by 3.5 ± 5.7 kg (p = 0.002), and underestimated FM% by 2.98 ± 4.7% (p = 0.002). The ECW/ICW ratio showed a significant and positive correlation with the difference BIA-D for FFM (r = 0.49; p = 0.002). After surgery, the differences between BIA and D were not significant, and the estimation error of FFM did not correlate with the ECW/ICW ratio. Conclusions: BIA generates an underestimation of FM as reported in patients with severe and morbid obesity, which is attenuated after weight reduction, underestimating weight loss as FM and overestimating FFM loss. Future research may assess whether these errors are reproduced by other BIA devices.

Protein, amino acids and obesity treatment

Dietary proteins have been used for years to treat obesity. Body weight loss is beneficial when it concerns fat mass, but loss of fat free mass - especially muscle might be detrimental. This occurs because protein breakdown predominates over synthesis, thus administering anabolic dietary compounds like proteins might counter fat free mass loss while allowing for fat mass loss.Indeed, varying the quantity of proteins will decrease muscle anabolic response and increase hyperphagia in rodents fed a low protein diet; but it will favor lean mass maintenance and promote satiety, in certain age groups of humans fed a high protein diet. Beyond protein quantity, protein source is an important metabolic regulator: whey protein and plant based diets exercize favorable effects on the risk of developing obesity, body composition, metabolic parameters or fat free mass preservation of obese patients. Specific amino-acids like branched chain amino acids (BCAA), methionine, tryptophan and its metabolites, and glutamate can also positively influence parameters and complications of obesity especially in rodent models, with less studies translating this in humans.Tuning the quality and quantity of proteins or even specific amino-acids can thus be seen as a potential therapeutic intervention on the body composition, metabolic syndrome parameters and appetite regulation of obese patients. Since these effects vary across age groups and much of the data comes from murine models, long-term prospective studies modulating proteins and amino acids in the human diet are needed.

Increase in Protein Intake After 3 Months of RYGB Is an Independent Predictor for the Remission of Obesity in the First Year of Surgery

INTRODUCTION

Although bariatric surgery promotes dietary changes, many questions regarding their effect on weight loss remain unanswered.

OBJECTIVE

The aim of this study was to evaluate changes in dietary intake and predictive factors of obesity remission in the first 12 months after RYGB.

METHODS

Fifty-one patients (mean 39.34 ± 9.38 years, 68.7% women) who underwent RYGB were included in this study. Dietary intake was evaluated through a 24-h dietary recall and subsequently classified by NOVA, macronutrients and calories. The predictive factors for obesity remission within 12 months after RYGB were evaluated by Cox regression.

RESULTS

At baseline, 62.7% of the patients presented severe obesity; mean excess weight loss was greater than 80% after 1 year of surgery and about 70% of the patients were no longer diagnosed with obesity. An increase in percentage of calories from protein was observed at 3 and 12 months after surgery. The caloric contribution of ultra-processed foods was low at 3 months after surgery while that of unprocessed or minimally processed foods was high at 3 and 12 months after surgery. From the Cox regression analysis, preoperative BMI (HR, 0.78; 95% CI, 0.69-0.88) and age (HR, 0.94; 95% CI, 0.89-0.99) showed an inverse association with obesity remission. Also, Δ protein (at 3 months-baseline) showed a positive association with obesity remission (HR, 1.06; 95% CI, 1.01-1.12).

CONCLUSION

Lower preoperative BMI, lower age, and higher protein intake at 3 months after surgery may favor remission of obesity in up to 12 months compared with baseline.

Dietary Recommendations for Bariatric Patients to Prevent Kidney Stone Formation

Bariatric surgery (BS) is one of the most common and efficient surgical procedures for sustained weight loss but is associated with long-term complications such as nutritional deficiencies, biliary lithiasis, disturbances in bone and mineral metabolism and an increased risk of nephrolithiasis, attributed to urinary metabolic changes resultant from low urinary volume, hypocitraturia and hyperoxaluria. The underlying mechanisms responsible for hyperoxaluria, the most common among all metabolic disturbances, may comprise increased intestinal oxalate absorption consequent to decreased calcium intake or increased dietary oxalate, changes in the gut microbiota, fat malabsorption and altered intestinal oxalate transport. In the current review, the authors present a mechanistic overview of changes found after BS and propose dietary recommendations to prevent the risk of urinary stone formation, focusing on the role of dietary oxalate, calcium, citrate, potassium, protein, fat, sodium, probiotics, vitamins D, C, B6 and the consumption of fluids.

Gut microbiota differs a decade after bariatric surgery relative to a nonsurgical comparison group

BACKGROUND

Few studies have assessed differences in the gut microbiota composition after bariatric surgery in the long term or whether differences are correlated with remission of type 2 diabetes.

OBJECTIVES

This observational study assessed differences in the gut microbiota between individuals at up to 13 years after surgery and a comparison group of individuals with severe obesity. The relationship between type 2 diabetes remission and the gut microbiota was also assessed.

SETTING

University.

METHODS

Stool samples were collected from individuals completing bariatric surgery (surgery group; n = 16) and individuals with severe obesity that did not receive surgery (nonsurgery group; n = 19) as part of the 12-year follow-up in the Utah Obesity Study. Metabolic health data were collected at baseline and the follow-up examination. The gut microbiota was quantified by sequencing the V4 region of the 16 S rRNA gene. Significant differences in microbiota composition with surgery and other covariates were determined by Unifrac distance analysis and permutational multivariate analysis of variance. Significant differences in the relative abundance of individual bacterial taxa were assessed using analysis of composition of microbiomes software.

RESULTS

The surgery group had higher relative abundances of Verrucomicrobiaceae (5.7 ± 1.3% versus 1.1 ± .3%) and Streptococcaceae (6.3 ± 1.0% versus 3.2 ± .8%), but lower relative abundances of Bacteroidaceae (8.8 ± 1.8% versus 18.6 ± 2.3%) 10.6 years after surgery. In a small subset of 8 individuals, a higher relative abundance of Akkermansia muciniphila was correlated with type 2 diabetes remission.

CONCLUSIONS

Differences in the gut microbiota are evident a decade after bariatric surgery compared with individuals with severe obesity that did not undergo surgery. The observed long-term differences are consistent with previous findings.

Prospective Longitudinal Trends in Body Composition and Clinical Outcomes 3 Years Following Sleeve Gastrectomy

BACKGROUND AND AIMS

Longitudinal assessment of body composition following bariatric surgery allows monitoring of health status. Our aim was to elucidate trends of anthropometric and clinical outcomes 3 years following sleeve gastrectomy (SG).

METHODS

A prospective cohort study of 60 patients who underwent SG. Anthropometrics including body composition analysis measured by multi-frequency bioelectrical impedance analysis, blood tests, liver fat content measured by abdominal ultrasound and habitual physical activity were evaluated at baseline and at 6 (M6), 12 (M12), and 36 (M36) months post-surgery.

RESULTS

Sixty patients (55% women, age 44.7 ± 8.7 years) who completed the entire follow-up were included. Fat mass (FM) was reduced significantly 1 year post-surgery (55.8 ± 11.3 to 26.7 ± 8.3 kg; P < 0.001) and then increased between 1 and 3 years post-operatively, but remained below baseline level (26.7 ± 8.3 to 33.1 ± 11.1 kg; P < 0.001). Fat free mass (FFM) decreased significantly during the first 6 months (64.7 ± 14.3 to 56.9 ± 11.8 kg; P < 0.001), slightly decreased between M6 and M12 and then reached a plateau through M36. Weight loss "failure" (< 50% excess weight loss) was noticed in 5.0% and 28.3% of patients at M12 and M36, respectively. Markers of lipid and glucose metabolism changed thereafter in parallel to the changes observed in FM, with the exception of HDL-C, which increased continuingly from M6 throughout the whole period analyzed (45.0 ± 10.2 to 59.5 ± 15.4 mg/dl; P < 0.001) and HbA1c which continued to decrease between M12 and M36 (5.5 ± 0.4 to 5.3 ± 0.4%; P < 0.001). There were marked within-person variations in trends of anthropometric and clinical parameters during the 3-year follow-up.

CONCLUSIONS

Weight regain primarily attributed to FM with no further decrease in FFM occurs between 1 and 3 years post-SG. FM increase at mid-term may underlie the recurrence of metabolic risk factors and can govern clinical interventions.

Bioimpedance phase angle is associated with serum transthyretin but not with prognostic inflammatory and nutritional index during follow-up of women submitted to bariatric surgery

BACKGROUND & AIMS

Phase angle (PhA) has been used as a prognostic indicator in several clinical situations. However, the use of PhA as a prognostic tool in bariatric patients is less known. The aim of this study was to evaluate PhA as a prognostic index and its correlation with the prognostic inflammatory and nutritional index (PINI) during follow-up of women subjected to bariatric surgery.

METHODS

Twenty female volunteers were studied. Body weight, body mass index (BMI), PhA, and biochemical components of PINI [serum C-reactive protein, alpha-1-acid glycoprotein, albumin, and transthyretin (TTR) concentrations] were evaluated at three time points: before (T0) and approximately 2-3 (T1) and 6 (T2) months after surgery. One-way repeated measures ANOVA or the Friedman test with Tukey's post hoc test was used depending on data normality. The associations between PhA and the other parameters were evaluated using Spearman's (nonparametric data) or Pearson's (parametric data) correlation coefficient.

RESULTS

Phase angle reduction was accompanied by a significant decrease in body weight and BMI at T1 (P < 0.05), but not at T2 (P > 0.05). PINI indicated low-risk complications during the preoperative period and no risk during the postoperative period (T1 and T2). No significant correlation was observed between PhA and PINI (P > 0.05). Regarding its association with the biochemical components of PINI, lower PhA values were significantly correlated with lower serum TTR concentrations (r = 0.633, P < 0.001).

CONCLUSIONS

Phase angle was not associated with PINI, although lower values were correlated with lower serum TTR, suggesting that PhA reduction is associated with an increased nutritional risk.

Vertical Sleeve Gastrectomy Attenuates Hedonic Feeding Without Impacting Alcohol Drinking in Rats

OBJECTIVE

Roux-en-Y gastric bypass surgery and vertical sleeve gastrectomy (VSG) are the most commonly performed bariatric procedures. Whereas studies report new-onset alcohol misuse following Roux-en-Y gastric bypass, the impact of VSG on alcohol intake is less clear. Hedonic feeding, alcohol drinking, and hypothalamic obesity-related gene expression following VSG were evaluated.

METHODS

Male Long-Evans rats underwent VSG or sham surgery. To evaluate hedonic feeding, rats received a high-fat diet following behavioral satiation on chow. Alcohol (5%-10% v/v) drinking was assessed in a two-bottle choice paradigm. Finally, polymerase chain reaction array evaluated gene expression.

RESULTS

VSG induced moderate but significant weight loss. Sham rats significantly escalated high-fat diet intake following behavioral satiation, an effect significantly reduced in VSG rats. A moderate decrease in alcohol intake was observed in VSG rats at low (5%) alcohol concentration. However, overall, no significant between-group differences were evident. Key hypothalamic orexigenic transcripts linked to stimulation of food and alcohol intake were significantly decreased in VSG rats.

CONCLUSIONS

VSG attenuated hedonic feeding without impacting alcohol drinking, an effect potentially mediated by alterations in genetic information flow within the hypothalamus. Importantly, these data highlight VSG as an effective bariatric procedure with a potentially reduced risk of developing alcohol use disorder.

Understanding Human Physiological Limitations and Societal Pressures in Favor of Overeating Helps to Avoid Obesity

Fat gain in our United States (US) environment of over-abundant, convenient, and palatable food is associated with hypertension, cardiovascular disease, diabetes, and increased mortality. Fuller understanding of physiological and environmental challenges to healthy weight maintenance could help prevent these morbidities. Human physiological limitations that permit development of obesity include a predilection to overeat palatable diets, inability to directly detect energy eaten or expended, a large capacity for fat storage, and the difficulty of losing body fat. Innate defenses resisting fat loss include reduced resting metabolism, increased hunger, and high insulin sensitivity, promoting a regain of fat, glycogen, and lean mass. Environmental challenges include readily available and heavily advertised palatable foods, policies and practices that make them abundant, less-than-ideal recommendations regarding national dietary macronutrient intake, and a frequently sedentary lifestyle. After gaining excess fat, some metabolic burdens can be mitigated though thoughtful selection of nutrients. Reduced dietary salt helps lower hypertension, less dietary sugar lowers risk of cardiovascular disease and obesity, and reducing proportion of dietary carbohydrates lowers post-meal insulin secretion and insulin resistance. Food intake and exercise should also be considered thoughtfully, as exercise in a fasted state and before the meals raises glucose intolerance, while exercising shortly after eating lowers it. In summary, we cannot directly detect energy eaten or expended, we have a genetic predisposition to eat palatable diets even when not hungry, and we have a large capacity for fat storage and a difficult time permanently losing excess fat. Understanding this empowers individuals to avoid overeating and helps them avoid obesity.