Very low-calorie diet in candidates for bariatric surgery: change in body composition during rapid weight loss

Preoperative Assessment of a Patient Undergoing Bariatric Surgery

Over the past few decades, obesity rates in the United States have risen drastically, and with this, there has been a rising demand for bariatric surgery. As such, anesthesiologists need to be familiar with the challenges presented by patients seeking bariatric surgery. Obesity causes pathophysiologic changes which may affect decision-making during the management of these patients. Patients seeking bariatric surgery also have a long, prescribed preoperative course that offers anesthesiologists the opportunity to be involved earlier during the pre-surgical evaluation and optimization process.

Evaluate the Effects of Different Types of Preoperative Restricted Calorie Diets on Weight, Body Mass Index, Operation Time and Hospital Stay in Patients Undergoing Bariatric Surgery: a Systematic Review and Meta Analysis Study

Previous studies investigated low-calorie diets (LCD), very-low-calorie diets (VLCD), and very-low-calorie ketogenic diets (VLCKD) in relation to weight loss and outcomes for bariatric surgery patients. However, the overall effects of these diets on various outcomes remain unclear. This study aimed to assess the impact of preoperative restricted calorie diets on weight, body mass index (BMI), operation time (OT), and hospital stay (HS) in bariatric surgery patients. Seventeen articles were analyzed, revealing the highest weight loss (-8.62) and BMI reduction (-5.75) with VLCKD. Due to insufficient data, the impact of these diets on OT and HS could not be determined. Further interventional studies are required to determine the ideal preoperative diet that achieves optimal weight loss, patient compliance, tolerance, acceptance, and surgical outcomes.

Obesity and malnutrition in children and adults: A clinical review

Background

In the U.S., children and adults are consuming more low-nutrient foods with added sugar and excess fats as compared to healthy, high-quality calories and micronutrients. This diet is increasing the prevalence of malnutrition and nutritional deficiencies, despite high calorie intake. This is a review of the common micronutrient deficiencies, the risk factors for malnutrition, dietary plans, and the health consequences in children and adults with obesity in the U.S.

Methods

This clinical review of literature was performed on the MEDLINE (PubMed) search engine. A total of 1391 articles were identified and after review, a total of 130 were found to be most pertinent.

Discussion

The most common micronutrient deficiencies found in patients with obesity were vitamin A, thiamine (B1), folate (B9), cobalamin (B12), vitamin D, iron, calcium, and magnesium, especially prior and after bariatric surgery. Diets that produced the most weight reduction also further puts these individuals at risk for worsening malnutrition. Malnutrition and micronutrient deficiencies can worsen health outcomes if not properly managed.

Conclusion

Adequate screening and awareness of malnutrition can improve the health outcomes in patients with obesity. Physiologic changes in response to increased adiposity and inadequate intake increase this population's risk of adverse health effects. Malnutrition affects the individual and contributes to worse public health outcomes. The recommendations for screening for malnutrition are not exclusive to individuals undergoing bariatric procedures and can improve the health outcomes of any patient with obesity. However, clearly, improved nutritional status can assist with metabolism and prevent adverse nutritional outcomes post-bariatric surgery. Clinicians should advise on proper nutrition and be aware of diets that worsen deficiencies.

The impact and utility of very low-calorie diets: the role of exercise and protein in preserving skeletal muscle mass

PURPOSE OF REVIEW

Very low-calorie diets (VLCD) are used as a weight loss intervention, but concerns have been raised about their potential negative impact on lean mass. Here, we review the available evidence regarding the effects of VLCD on lean mass and explore their utility and strategies to mitigate reductions in skeletal muscle.

RECENT FINDINGS

We observed that VLCD, despite their effects on lean mass, may be suitable in certain populations but have a risk in reducing lean mass. The extent of the reduction in lean mass may depend on various factors, such as the duration and degree of energy deficit of the diet, as well as the individual's starting weight and overall health.

SUMMARY

VLCD may be a viable option in certain populations; however, priority needs to be given to resistance exercise training, and secondarily to adequate protein intake should be part of this dietary regime to mitigate losing muscle mass.

Increased Hepatic ATG7 mRNA and ATG7 Protein Expression in Nonalcoholic Steatohepatitis Associated with Obesity

The autophagy gene ATG7 has been shown to be essential for the induction of autophagy, a process that used to be suppressed in nonalcoholic fatty liver disease (NAFLD). However, the specific role of ATG7 in NAFLD remains unclear. The aim of this study was to analyze hepatic ATG7 mRNA and ATG7 protein expression regarding obesity-associated NAFLD. Patients included women classified into normal weight (NW, n = 6) and morbid obesity (MO, n = 72). The second group was subclassified into normal liver (NL, n = 11), simple steatosis (SS, n= 29), and nonalcoholic steatohepatitis (NASH, n = 32). mRNA expression was analyzed by RT-qPCR and protein expression was evaluated by Western blotting. Our results showed that NASH patients presented higher ATG7 mRNA and ATG7 protein levels. ATG7 mRNA expression was increased in NASH compared with SS, while ATG7 protein abundance was enhanced in NASH compared with NL. ATG7 mRNA correlated negatively with the expression of some hepatic lipid metabolism-related genes and positively with endocannabinoid receptors, adiponectin hepatic expression, and omentin levels. These results suggest that ATG7-mediated autophagy may play an important role in the pathogenesis of NAFLD, especially in NASH, perhaps playing a possible protective role. However, this is a preliminary study that needs to be further studied.

Effectiveness and Tolerability of a Two-Week Hypocaloric Protein-Rich Diet Prior to Obesity Surgery with Two Different Diet Interventions: a Prospective Randomized Trial

Purpose

Preoperative very low-calorie diets (VLCDs) have been shown to reduce liver volume and improve bariatric surgery safety. Here, we compare two VLCD that differ in macronutrient composition.

Material/Methods

Ninety patients awaiting obesity surgery were included in a prospective, open-label, randomized mono-centre trial comparing the effects of 2-week preoperative VLCDs: BCM Diät™ (diet 1) versus Optifast™ (diet 2).

Results

Data from 33 patients in diet 1 and 36 in diet 2 could be analysed. There was no significant difference between the two diet intervention arms on outcome parameters. Overall, both VLCD strategies led to a mean weight reduction of 5.24 [4.72–5.76] kg (p < 0.001), mean excess weight loss was 8.2 [7.4–9.1] % (p < 0.001). BMI reduction was 1.81 [1.63–1.99] kg/m² (p < 0.001). Over all patients, the liver volume was reduced by 397 [329–466] ml (p < 0.001), which corresponds to 14.6 [12.4; 16.8] %. Liver fat content was significantly reduced by 18.35 [8.98–27.71] %. Reduction of body weight correlates with liver volume loss.

In addition, hip/waist circumferences, body fat and fat-free mass decreased significantly. We found an increase of ALAT/ASAT and a significant decrease of triglycerides, LDL-cholesterol and HbA1c. Parameters of inflammatory were significantly reduced upon VLCD.

Conclusion

Independently of the macronutrient composition, VLCD leads to a significant decrease of body weight, reduction of liver volume and improved parameters of inflammation, glucose and lipid metabolism. Preoperative diets are widely used in conditioning; however, VLCD should be considered as option for patients with obesity undergoing other abdominal surgeries.

Graphical abstract

FOOD TOLERANCE AND NUTRITIONAL RISK AFTER SLEEVE GASTRECTOMY AND ROUX-EN-Y GASTRIC BYPASS IN ELDERLY PATIENTS WITH SEVERE OBESITY: A PROSPECTIVE, RANDOMIZED CONTROLLED TRIAL

BACKGROUND

Bariatric surgery is still controversial in elderly patients with severe obesity. Most publications focus on safety and early clinical outcomes. Food tolerance and nutritional postoperative risk is unknown for this population.

METHODS

Thirty-six elderly patients with severe obesity were recruited for an open-label randomized trial from September 2017 to May 2019 comparing laparoscopic sleeve gastrectomy (LSG) to Roux-en-Y Gastric Bypass (LRYGB). Food tolerance was accessed by Quality of Alimentation (QoA) questionnaire and data on weight loss, body composition, and nutritional risk were collected between 6 and 24 months after surgery.

RESULTS

Comparing LSG to LRYGB patients, the latter had higher total weight loss (22% vs 31%, P=0.01) and excess weight loss (53% vs 68%, P=0.01). Food tolerance to eight food groups was similar between groups (14 vs 15 points, P=0.270), as Suter score (23 vs 25, P=0.238). Daily protein intake was below recommendation in both groups (40 vs 51 g/d, P=0.105). Nutritional risk, evaluated through Standardized Phase Angle (-1.48 vs -1.99, P=0.027), was worse for LRYGB group.

CONCLUSION

Food tolerance and adequacy of food consumption were similar in both groups. LRYGB patients had higher nutritional risk.

Measuring ketone bodies for the monitoring of pathologic and therapeutic ketosis

BACKGROUND

The ketone bodies β-hydroxybutyrate (BOHB) and acetone are generated as a byproduct of the fat metabolism process. In healthy individuals, ketone body levels are ∼0.1 mM for BOHB and ∼1 part per million for breath acetone (BrAce). These levels can increase dramatically as a consequence of a disease process or when used therapeutically for disease treatment. For example, increased ketone body concentration during weight loss is an indication of elevated fat metabolism. Ketone body measurement is relatively inexpensive and can provide metabolic insights to help guide disease management and optimize weight loss.

METHODS

This review of the literature provides metabolic mechanisms and typical concentration ranges of ketone bodies, which can give new insights into these conditions and rationale for measuring ketone bodies.

RESULTS

Diseases such as heart failure and ketoacidosis can affect caloric intake and macronutrient management, which can elevate BOHB 30-fold and BrAce 1000-fold. Other diseases associated with obesity, such as brain dysfunction, cancer, and diabetes, may cause dysfunction because of an inability to use glucose, excessive reliance on glucose, or poor insulin signaling. Elevating ketone body concentrations (e.g., nutritional ketosis) may improve these conditions by forcing utilization of ketone bodies, in place of glucose, for fuel. During weight loss, monitoring ketone body concentration can demonstrate program compliance and can be used to optimize the weight-loss plan.

CONCLUSIONS

The role of ketone bodies in states of pathologic and therapeutic ketosis indicates that accurate measurement and monitoring of BOHB or BrAce will likely improve disease management. Bariatric surgery is examined as a case study for monitoring both types of ketosis.

Neck circumference in Latin America and the Caribbean: A systematic review and meta-analysis

Background: High neck circumference (NC) is associated with high burden diseases in Latin American and the Caribbean (LAC). NC complements established anthropometric measurements for early identification of cardio-metabolic and other illnesses. However, evidence about NC has not been systematically studied in LAC. We aimed to estimate the mean NC and the prevalence of high NC in LAC.

Methods: We conducted a systematic review in MEDLINE, Embase, Global Health and LILACS. Search results were screened and studied by two reviewers independently. To assess risk of bias of individual studies, we used the Hoy et al. scale and the Newcastle-Ottawa scale. We conducted a random-effects meta-analysis.

Results: In total, 182 abstracts were screened, 96 manuscripts were reviewed and 85 studies (n= 51,978) were summarized. From all the summarized studies, 14 were conducted in a sample of the general population, 23 were conducted with captive populations and 49 studies were conducted with patients. The pooled mean NC in the general population was 35.69 cm (95% IC: 34.85cm-36.53cm; I²: 99.6%). In our patient populations, the pooled mean NC in the obesity group was 42.56cm (95% CI 41.70cm-43.42cm; I²: 92.40%). Across all studied populations, there were several definitions of high NC; thus, prevalence estimates were not comparable. The prevalence of high NC ranged between 37.00% and 57.69% in the general population. The methodology to measure NC was not consistently reported.

Conclusions: Mean NC in LAC appears to be in the range of estimates from other world regions. Inconsistent methods and definitions hamper cross-country comparisons and time trend analyses. There is a need for consistent and comparable definitions of NC so that it can be incorporated as a standard anthropometric indicator in surveys and epidemiological studies.

Non-Surgical Interventions for Hospitalized Adults with Class II or Class III Obesity: A Scoping Review

Adult inpatients with Class II or III obesity and comorbidities have a high health burden with frequent hospitalizations. Surgical risk and patient choice can be contraindications to bariatric surgery, which is considered the gold standard treatment. The best approach to non-surgical management for this adult inpatient group is currently unknown. The aim of this scoping review was to summarize current research in the inpatient setting. The unpublished literature and six electronic database searches identified 4,582 articles, with 12 articles (reporting on 10 studies) eligible and included. The literature on the interventions and their key components in the non-surgical care of the adult inpatient with Class II or III obesity were mapped identifying service provision successes and gaps. The articles reported on intensive lifestyle interventions, comparison of oxygen administration regimes, total parenteral nutrition regimens, and pre-surgical rapid weight loss. Study designs included evaluation (n=1), before-after intervention studies (n=3), and randomized/non-randomized controlled trials (n=6). The classification of obesity as a chronic disease is not universal resulting in reduced inpatient treatment options. Recommendations for consumers, practitioner practice, health policy-makers and future research priorities are reported. Further research in the development of cost-effective inpatient models of care is indicated.

Body Composition Changes Following a Very-Low-Calorie Pre-Operative Diet in Patients Undergoing Bariatric Surgery

BACKGROUND

Fatty liver in obese patients increases the technical difficulty of bariatric surgery. Pre-operative weight loss with a very-low-calorie diet (VLCD) is commonly used to facilitate surgery. Few studies have quantified the systemic effect of rapid pre-operative weight loss on body composition. The objective of this study is to evaluate body composition changes in bariatric surgery patients undergoing a VLCD.

METHODS

Body composition assessments were performed between August 2017 and January 2019 using dual-energy X-ray absorptiometry immediately before and after a 2-week VLCD at St Vincent's Hospital Melbourne. Data collected prospectively pre- and post-VLCD included total body weight, excess body weight, body mass index (BMI), lean body mass (LBM), fat mass (FM) and bone mineral content (BMC). The pre- and post-operative results were compared.

RESULTS

Forty-four patients completed both the 2-week VLCD and body composition assessments. Following a 2-week VLCD, patients lost a mean of 4.5 kg (range - 0.3 to 9.5) in a total body weight and 8.8% (range - 0.9 to 17.1) of excess body weight, with a mean reduction in body mass index of 1.6 kg/m² (range - 0.2 to 3.1). Loss of LBM was 2.8 kg and was significantly greater than loss of FM, 1.7 kg (p < 0.05). BMC changes were insignificant.

CONCLUSION

A VLCD is an effective tool for pre-operative weight reduction. In this cohort, a large amount of the total weight loss was attributed to a loss of lean body mass. The impact of significant lean body mass loss and its relationship to short- and long-term health outcomes warrants further assessment.

Challenges and outcomes for bariatric surgery in patients with paraplegia: Case series and systematic review

INTRODUCTION

Obesity contributes to a plethora of significant chronic diseases. Bariatric surgery has been demonstrated to be the most cost-effective treatment for severe obesity and significantly reduces morbidity and mortality from metabolic syndrome. Patients with paraplegia have significantly impaired mobility and are therefore at a much higher risk of developing severe obesity and its sequelae. Bariatric surgery may bring significant improvements to mobility, morbidity and quality of life for patients with paraplegia, but evidence in the literature is poor for this group of patients.

METHODS

A systematic review was conducted conforming to PRISMA guidelines. The MEDLINE and Cochrane databases were searched for all articles published prior to April 2019 matching all of the keywords 'bariatric', 'paraplegia' and 'spinal cord'. Articles were assessed for relevance and full texts reviewed. In addition, clinical records were reviewed for three patients who underwent bariatric surgery at a single UK private institution. Non-identifiable demographic, clinical, operative and outcome data were obtained from electronic records.

RESULTS

Twenty seven articles were retrieved from the initial database search, of which nine eligible full texts were reviewed. Eight articles were case reports or case series and the final article was a systematic review. All cases reported had positive outcomes with significant weight loss, improvement in mobility and increased quality of life. Outcomes from the three diversely aged patients in our case series were similarly positive, with no significant post-operative complications.

DISCUSSION

Patients with obesity and paraplegia may significantly benefit from bariatric surgery. There is a need for multi-centre cohort studies to evaluate outcomes and the choice of bariatric intervention. UK guidelines do not include criteria based on mobility or neurological deficit, resulting in a potential missed opportunity to offer a cost-effective treatment that can significantly improve quality of life for patients with severe obesity and paraplegia.

Establishment of Adequate Nutrient Intake Criteria to Achieve Target Weight Loss in Patients Undergoing Bariatric Surgery

Although bariatric surgery is the best treatment modality for morbidly obese patients, a 10-30% rate of weight recidivism has been reported in various specialized centers. We examined changes in energy and macronutrients after bariatric surgery and performed analysis to establish appropriate nutritional guidelines for reaching the target percentage of weight loss after surgery. A total of 189 subjects who underwent bariatric surgery were classified into success and failure groups depending on whether or not they reached 50% loss of excess weight at 12 months after bariatric surgery. Physical examinations and dietary surveys were completed before and 1, 6, and 12 months after surgery. Using receiver operating characteristic (ROC) analysis, the optimal cutoff points for nutrient intakes for determining success after bariatric surgery were computed based on maximal Youden's index. At 6 and 12 months after surgery, the success group had significantly lower carbohydrate and fat intakes than the failure group. The cutoff calorie intake for success in weight loss was <835.0, <1132.5, and <1523.0 kcal/day at 1, 6, and 12 months post operation, respectively. With regard to protein, the cutoff intakes were >44.5, >41.5, and >86.5 g/day at 1, 6, and 12 months post operation, respectively. At 12 months, the cutoff ratio for energy obtained from carbohydrates, protein, and fat was <49.0, >24.5, and <28.0%, respectively. Our findings confirm that the level of diet control and nutrition restriction affect the achievement of target weight loss, emphasizing that long-term weight loss is related to compliance with nutrient recommendations.