Loss Of Fat-free Mass Research Articles

Glucagon-like peptide-1 receptor agonist-based agents and weight loss composition: Filling the gaps.

Excess adiposity is at the root of type 2 diabetes (T2D). Glucagon-like peptide-1 receptor agonists (GLP-1RAs) have emerged as first-line treatments for T2D based on significant weight loss results. The composition of weight loss using most diets consists of <25% fat-free mass (FFM) loss, with the remainder from fat stores. Higher amounts of weight loss (achieved with metabolic bariatric surgery) result in greater reductions in FFM. Our aim was to assess the impact that GLP-1RA-based treatments have on FFM. We analysed studies that reported changes in FFM with the following agents: exenatide, liraglutide, semaglutide, and the dual incretin receptor agonist tirzepatide. We performed an analysis of various weight loss interventions to provide a reference for expected changes in FFM. We evaluated studies using dual-energy X-ray absorptiometry (DXA) for measuring FFM (a crude surrogate for skeletal muscle). In evaluating the composition of weight loss, the percentage lost as fat-free mass (%FFML) was equal to ΔFFM/total weight change. The %FFML using GLP-1RA-based agents was between 20% and 40%. In the 28 clinical trials evaluated, the proportion of FFM loss was highly variable, but the majority reported %FFML exceeding 25%. Our review was limited to small substudies and the use of DXA, which does not measure skeletal muscle mass directly. Since FFM contains a variable amount of muscle (approximately 55%), this indirect measure may explain the heterogeneity in the data. Assessing quantity and quality of skeletal muscle using advanced imaging (magnetic resonance imaging) with functional testing will help fill the gaps in our current understanding.

Changes in hormonal profiles during competition preparation in physique athletes.

Physique athletes engage in rigorous competition preparation involving intense energy restriction and physical training to enhance muscle definition. This study investigates hormonal changes and their physiological and performance impacts during such preparation. Participants included female (10 competing (COMP) and 10 non-dieting controls (CTRL)) and male (13 COMP and 10 CTRL) physique athletes. COMP participants were tested 23weeks before (PRE), one week before (MID), and 23weeks after the competition (POST). Non-dieting CTRL participants were tested at similar intervals. Measurements included body composition (DXA), muscle cross-sectional area (ultrasound), energy availability (EA) derived by subtracting exercise energy expenditure (EEE) from energy intake (EI) and dividing by fat-free mass (FFM), muscle strength, and various serum hormone concentrations (ACTH, cortisol, estradiol, FSH, IGF-1, IGFBP-3, insulin, and free and total testosterone and SHBG). During the diet, EA (p < 0.001), IGF-1 (p < 0.001), IGFBP-3 (p < 0.01), and absolute muscle strength (p < 0.01-0.001) decreased significantly in both sexes in COMP. Decreases in IGF-1 were also associated with higher loss in FFM. In males, testosterone (p < 0.01) and free testosterone (p < 0.05) decreased, while SHBG (p < 0.001) and cortisol (p < 0.05) increased. Insulin decreased significantly only in males (p < 0.001). Mood disturbances, particularly increased fatigue in males (p < 0.05), highlighted the psychological strain of competition preparation. All these changes were restored by increased EA during the post-competition recovery period. Significant reductions in IGF-1 and IGFBP-3 during competition preparation may serve as biomarkers for monitoring physiological stress. This study offers valuable insights into hormonal changes, muscle strength, and mood state during energy-restricted intense training.

Protein Supplement Tolerability and Patient Satisfaction after Bariatric Surgery

PurposeDisproportional 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 MethodsNinety-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.ResultsSeven 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).ConclusionPES 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.Graphical

Metabolic adaptation following gastric bypass surgery: results from a 2-year observational study.

Metabolic adaptation is the lowering of basal metabolic rate (BMR) beyond what is predicted from changes in fat mass (FM) and fat-free mass (FFM) and may hamper weight-loss progression. It is unclear whether metabolic adaptation occurs following gastric bypass surgery (GBP) and if it persists. The aim of this study was to evaluate the reduction in BMR that is not explained by changes in body composition in patients following GBP compared to a weight-stable comparator group. Thirty-one patients [77.4% female; mean BMI 45.5(SD 7.0) kg/m2; age 47.4(11.6)y] who underwent GBP, and 32 time-matched comparators [50% female; BMI 27.2(4.6) kg/m2; age 41.8(13.6)y) were evaluated at 1-month pre-surgery, 3-, 12- and 24-months post-surgery. BMR was measured under standardised residential conditions using indirect calorimetry and body composition using DXA. Linear regression analyses assessed metabolic adaptation post-surgery. After surgery, patients lost a quarter of their body weight [-25.6%(1.8%); p < 0.0001] consisting mainly of FM (4:1 FM to FFM loss ratio) at 24-months post-surgery. Absolute BMR (MJ/d) reduced by 25.7% at 24-months post-surgery with values becoming similar to the comparator group from 3-months post-surgery. Positive associations were observed between changes in BMR and changes in FFM and FM (P < 0.03). Metabolic adaptation was present in patients during the 1) rapid weight loss phase (6.9 kg/month at 3-months post-surgery) (p = 0.011), 2) slower weight loss phase (1.6 kg/month from 3 to 12-months post-surgery) (p < 0.0001), and, 3) weight maintenance phase (24-months post-surgery) (p = 0.00073). However, the degree of metabolic adaptation observed in GBP patients was similar to the weight-stable comparator group (no metabolic adaptation) from 12-months post-surgery onwards (3-months; p = 0.01, 12-months; p = 0.26, 24-months post-surgery; p = 0.70). These results suggest that there is a potential biological mechanism of surgery that attenuates the expected postoperative downregulation in BMR thus helping GBP patients maintain weight loss.

Changes in Fat Mass Index and Fat-Free Mass Index Vary Significantly by Age and Sex of the Patient, and by Type of Bariatric Surgery.

The loss of fat-free mass after rapid weight loss following bariatric surgery shows BMI is inadequate for reporting weight loss, emphasizing the need for a more accurate body composition metric. This study assessed changes in fat mass index (FMI), fat-free mass index (FFMI), and dietary intake over 6months after one-anastomosis gastric bypass (OAGB), Roux-en-Y gastric bypass (RYGB), and sleeve gastrectomy (SG) across age and sex groups. This prospective observational study included 151 bariatric surgery candidates. Data on demographics, anthropometric, body composition, and food intake data were collected before and 6months after surgery. SPSS version 22 was used for analysis, employing ANOVA and t-tests to assess group differences. Younger patients (≤ 35years) had higher percent total and excess weight loss (%TWL and %EWL) across all bariatric surgeries, and those undergoing SG experienced more favorable changes in fat-free mass (FFM) and visceral fat compared to other procedures (P = 0.002). Males had higher percent change in fat mass index (%∆ FMI) and visceral fat than females with OAGB and RYGB (P < 0.05). Women undergoing SG and RYGB had a more significant decrease in energy intake compared to OAGB (P < 0.001), and the ≤ 35 and 35-44 age groups demonstrated lower reductions in energy intake following OAGB. Age, sex, and surgery type significantly affect bariatric surgery outcomes. Younger patients achieved greater weight-related improvements, while men undergoing RYGB experienced more substantial fat mass changes than women.

Major dietary patterns and their associations with total weight loss and weight loss composition 2–4 years after sleeve gastrectomy

BackgroundFood intakes 1–2 years following bariatric surgery depend more on patients than the surgery’s gastrointestinal tract changes. This study aimed to determine the major dietary patterns of patients after the first two years of sleeve gastrectomy and to investigate their associations with total weight loss (TWL) and the proportion of TWL as fat mass (FM) and fat-free mass (FFM) loss.MethodsThis cross-sectional study included 146 patients undergoing sleeve gastrectomy 2–4 years after surgery. Dietary patterns were determined using principal component analysis based on the 19 food groups. The percentage of FM loss relative to TWL (%FML) and FFM loss relative to TWL (%FFML) were calculated. A suboptimal clinical response was defined as a TWL of less than 25%. High FM loss and excessive FFM loss were defined based on the highest tertiles. Linear and logistic regression models were used to derive unstandardized (B) coefficients and odds ratios (OR), with dietary pattern scores serving as both a continuous and a binary variable (higher vs. lower adherence groups based on median).ResultsTwo predominant dietary patterns were retained. Each 1-unit increase in the first dietary pattern score characterized by high intakes of fast foods, soft drinks, processed meats, sugar confectionary, salty snacks, grains, and organ meats was associated with higher %FFML (B = 1.99; 95% confidence interval (CI) 0.34, 3.66), lower %FML (B = − 1.84; 95% CI − 3.49, − 0.20), and higher odds of excessive FFM loss (OR = 1.84; 95% CI 1.09, 3.11). Participants with higher adherence to the first dietary pattern had lower %TWL, and greater odds of suboptimal clinical response and excessive FFM loss than those with lower adherence. Each 1-unit increase in score for the second dietary pattern characterized by a high intake of fruits, dairy, vegetables, legumes, eggs, nuts, red meats, poultry, and fish was associated with lower odds of suboptimal clinical response (OR = 0.51; 95% CI 0.31, 0.86).ConclusionPatients should be encouraged to modify their diet by reducing the consumption of ultra-processed foods and increasing their intake of high-quality protein sources, fruits, and vegetables to achieve the best postoperative outcome.

Association Between Indole-3-Pyruvic Acid and Change in Fat-Free Mass Relative to Weight Loss in Patients Undergoing Sleeve Gastrectomy.

Sleeve gastrectomy typically leads to weight loss, including a reduction in fat-free mass (FFM). Studies have shown significant FFM loss within 1 year after the procedure but with individual variations. This study aimed to assess whether preoperative amino acid metabolite levels can predict FFM changes following sleeve gastrectomy. This study involved 42 patients. Body weight, fat mass (FM), and FFM were measured preoperatively and 3, 6, and 12 months postoperatively. All participants experienced weight loss, FM reduction, and FFM decrease for up to 3 months after surgery. However, the following distinct groups emerged from 3 to 6 months postoperatively: one showed FFM gain relative to weight loss, whereas the other exhibited continued FFM reduction relative to weight loss. This trend persisted for up to 12 months postoperatively and became more pronounced. The group with FFM gain had lower preoperative BMI and higher levels of indole-3-pyruvic acid (IPyA). Logistic regression and ROC curve analyses confirmed IPyA's ability to predict FFM gain between 3 and 6 months after sleeve gastrectomy, with a useful cutoff value of 20.205. Preoperative IPyA levels were associated with FFM gain relative to weight loss in the 3 to 6 months following sleeve gastrectomy. These findings suggest that IPyA may be a potential predictor for FFM changes during this period.

A systematic review of physical activity and nutritional interventions for the management of normal weight and overweight obesity

AimsNormal Weight Obesity (NWO) and Overweight Obesity (OWO) are prevalent conditions, yet knowledge of management is limited. This review aims to assess the effectiveness of physical activity and nutritional interventions in the management of NWO and OWO (together defined as BMI <30 kg/m2 with raised body fat). Data synthesisClinical trials including any physical activity or nutritional interventions, published between 2012 and 2022, evaluating body fat change were selected. Seven trials met inclusion criteria, including one single arm intervention, and six RCTs. A high intensity interval training intervention (high risk of bias) had the largest effect on reducing percentage body fat (MD: −6.8%, SE: 0.06). High protein intake interventions were also found to be effective (MD: −2.8%, SE: 0.27, MD: −2.0%, SE: 0.05). These three interventions led to greater increases in fat free mass. Two energy restricted interventions resulted in the highest mean weight loss (MD: −3.10 kg, SD: 0.87 (intervention only), MD: −2.90 kg, SE: 0.06), but also loss of fat free mass, resulting in low reductions in percentage body fat (MD: −1.10%, SD: 0.57 (intervention only), MD: −0.8%, SE 0.30). There was considerable heterogeneity between studies. ConclusionsThere are physical activity and nutritional interventions that could be efficacious for the management of NWO and OWO. However, there was considerable heterogeneity between studies. The most promising nutritional intervention is high protein intake and the least is energy restriction (without increased protein intake). More high-quality trials are needed to evaluate interventions, and to determine the best tools to measure adiposity.

The habitual degree of weight loss might be associated with specific fat and protein intakes during a period of weight maintenance in athletes used to weight variations: preliminary results from the WAVE study

Weight variations are common in sporting life, with important inter-individual variability in the degree of an athlete's habitual weight loss. As a part of the WAVE study (NCT04107545), the main objective of this preliminary study was to determine whether the habitual degree of weight loss was associated with anthropometric, body composition, nutritional or psychometric profiles during a period of weight maintenance in athletes accustomed to weight variations. We hypothesized that athletes accustomed to a higher habitual degree of weight loss may have a higher body weight and body fat mass, and may present a more controlled diet regimen and cognitive restriction than athletes with a lower habitual degree of weight loss. During a period of weight maintenance, 62 athletes (24.0 ± 5.3 years; 26 women) completed anthropometry and body composition measurements, a 48-hours food diary and self-reported questionnaires to determine their weight variation practice, nutritional profile and mood state. Athletes were stratified within inter- and intra-quartile groups according to their habitual degree of weight loss. Athletes with a higher habitual degree of weight loss were those who consumed more protein (P < .001) and less fat (P = .01) as a proportion of total energy compared with those losing less weight, without any difference in body composition between the groups. The rapid weight loss score was significantly higher in individuals losing more weight (P < .001) and no difference was observed for the mood state profile. The present results suggest a potential control of nutritional regulation during a period of weight maintenance in order to spare fat-free mass and favor fat mass loss in athletes who are routinely losing more weight. Fat-free mass may be the main nutritional driver due to low body fat mass in athletes, which may limit the “catch-up fat” phenomenon commonly observed in nonathletic population.

Long-Term Differential Effects of Gastric Bypass and Sleeve Gastrectomy on Bone Mineral Density

Abstract Context The association of obesity with bone fragility fractures is complex and non-linear. Despite good efficacy on weight loss, bariatric surgery (BS) is also associated with bone loss. However, we lack information on risk factors of the long-term deleterious effects of BS on the skeleton. Objective We aimed to assess the factors associated with low bone mineral density (BMD) performed a long time after Roux-en-Y gastric bypass (RYGB) or sleeve gastrectomy (SG). Methods This cross-sectional study involved patients at a long distance from their BS that underwent dual-energy x-ray absorptiometry (DXA) with biological factors (vitamins, micronutrients, bone and inflammation biomarkers). Simple and multiple linear models (stepwise and parsimony approach) were developed. Results A total of 131 patients (91 RYGB, 40 SG) underwent DXA (51.8 ± 11.08 years, 87.8% women). At a mean of 6.8 ± 3.7 years after surgery, the mean weight loss was –28.6 ± 9.6%, and only 6 patients (5.7%) had a T-score less than or equal to ­2.5. On univariate analysis, BMD was lower in the RYGB than in the SG group (P &amp;lt; .001) at all sites, despite similar fat and fat-free mass and weight loss. Serum parathyroid hormone and phosphate levels were higher in RYGB than SG patients. A total of 10.1% of patients showed vascular calcifications. On multivariable analysis, BMD remained different between surgery groups after adjustment for age, body mass index, ethnicity, and sex. The model-adjusted R2 values were 0.451 for the total hip; 0.462 the femoral neck, and 0.191 the lumbar spine for the inflammation model; 0.458, 0.462, and 0.254, respectively, for the bone marker model; and 0.372, 0.396, and 0.142 for the vitamin model. Serum zinc, ferritin, and uric acid levels were the markers associated with BMD to a low extent. Conclusion BMD differed depending on the BS procedure. A few biological markers may be associated weakly with BMD well after the surgery.

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.

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. 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. 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. 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.

A very-low-calorie ketogenic diet normalises obesity-related enhanced levels of erythropoietin compared with a low-calorie diet or bariatric surgery

PurposeNutritional ketosis synergistically with body-weight loss induced by a very-low-calorie ketogenic diet (VLCKD) has proven to be effective in improving obesity-related pathophysiology. Recently, growing attention has been focused on the relation between erythropoietin (EPO) and obesity. Thus, this study aims to investigate whether nutritional ketosis and weight loss induced by a VLCKD modify the circulating levels of EPO in patients with obesity in comparison with the effect of low-calorie diet (LCD) or bariatric surgery (BS).MethodsEPO levels, iron status and body composition parameters were evaluated in 72 patients with overweight or obesity and 27 normal-weight subjects at baseline and after the three different weight-reduction therapies (VLCKD, LCD and BS) in 69 patients with excess body weight. β-hydroxybutyrate levels were also measured in the VLCKD group. The follow-up was established at 2–3 months and 4–6 months.ResultsIt was found that EPO levels were higher in morbid obesity and correlated with higher basal weight, fat mass (FM) and fat-free mass (FFM) in the overall sample. High baseline EPO levels were also correlated with higher impact on the course of weight loss and changes in FM and FFM induced by the three weight-loss interventions. Furthermore, the VLCKD induced a decrease in EPO levels coinciding with maximum ketosis, which was maintained over time, while statistically significant changes were not observed after LCD and BS.ConclusionThe obesity-related increased EPO levels are restored after VLCKD intervention at the time of maximum ketosis, suggesting a potential role of the nutritional ketosis induced by the VLCKD. Baseline EPO levels could be a biomarker of response to a weight-loss therapy.Graphical abstract

Protein Supplements with Short Peptides Are Better than Complex Protein-Based Supplements on Improving Early Fat-Free Mass Loss Following Bariatric Surgery: A Retrospective Cohort Study.

Bariatric surgery (BS) patients are advised to consume protein supplements to prevent fat-free mass (FFM) loss. However, limited research has explored the efficacy of diverse protein presentations on FFM preservation. This study assesses if short peptide-based (SPB) supplements surpass complex protein-based (CPB) supplements in reducing early FFM loss post-surgery. In this retrospective cohort study, 138 patients who underwent BS other than Roux-en-Y-gastric bypass (RYGB) between January 2021 and March 2021 at the Department of Bariatric Surgery of the Third People's Hospital of Chengdu were included for analysis. Patients were divided into two groups based on their consumption of protein supplements after surgery: SPB group and CPB group. Multiple linear regressions separated by sex were employed to examine the associations between SPB supplements and FFM loss and percentage of FFM (%FFM) loss, respectively. Among participants, 69.6% were female, with a mean age of 33.3years. In multiple linear regression analyses, SPB supplements were significantly and positively associated with a lower FFM loss in both female (ꞵ = - 1.14, P = 0.047) and male (ꞵ = - 2.36, P = 0.024), and were positively associated with a lower %FFM loss in both female (ꞵ = - 1.83) and male (ꞵ = - 2.26) but only significant in male (P = 0.049). SPB supplements may be more effective in preventing early FFM loss after BS, compared to CPB supplements, particularly among male patients. Therefore, SPB supplements may be recommended to patients undergoing BS. Further research is needed to validate these findings.

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 & AimsThere 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. MethodsElectronic 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 weight loss (%TWL), were eligible. For each outcome, the mean and standard deviation (for changes from baseline) were used to synthesize the data. ResultsEight 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 kg) 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 gatsrectomy (LSG) (MD: 6.52 kg; 95% CI: 0.99 to 12.02). ConclusionThe 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.

Post-restriction hyperphagia and metabolic responses to short-term calorie restriction in C57BL/6 mice

Aims: To evaluate post-restriction hyperphagia (PRH) responses to short-term calorie restriction (CR) and the potential drivers of this behaviour. Methods: Adult male C57BL/6J mice underwent 30% CR for 5 to 30 days, then refed for 12 days. Energy intake, body mass, fat mass, fat-free mass, body temperature, and physical activity were measured continuously throughout the CR and re-feeding phases and daily energy expenditure was measured over final 2 days of CR and the first 5 days of re-feeding. Results: Following restriction, energy intake, body mass, fat free mass, body temperature and daily energy expenditure were reduced in all groups compared to controls (P&lt;0.05). Only the 20d and 25d groups had significantly lower fat mass than controls (P=0.004). Total physical activity and dark-phase physical activity did not differ between control and CR groups (P=0.446 and 0.380 respectively); but light-phase physical activity of groups 20d, 25d and 30d increased significantly (P&lt;0.001) due to food anticipatory activity. All CR groups displayed peak PRH on day1 of refeeding. Total energy intake over the following 2-5 days of refeeding was also greater than the controls (P=0.002). The magnitude of PRH increased with CR duration and body mass loss at the individual level (P&lt;0.001). In a multiple regression analysis fat free mass loss was the main factor that was correlated with the level of PRH (Multiple regression R2=32.7%, fat mass P=0.036, fat free mass P=0.003). Conclusion: Hunger (reflected by PRH) was mostly related to body mass and fat free mass loss. The effect of fat free mass loss was the opposite of that expected if fat free mass is a key driver of food intake as recently postulated. Developing restriction protocols that minimize loss of fat free mass may reduce the level of hunger that emerges when individuals are under restriction.

Association of postoperative dietary macronutrient content and quality with total weight loss and fat-free mass loss at midterm after sleeve gastrectomy

ObjectivesThis study aimed to investigate the associations of macronutrient quantities and qualities with percentage total weight loss and percentage of fat-free mass loss relative to total weight loss in adults undergoing sleeve gastrectomy. MethodsThis cross-sectional study included 146 patients on postoperative time since sleeve gastrectomy of 2 to 4 y. Diet was assessed using a food frequency questionnaire. Macronutrient quality index, carbohydrate quality index, fat quality index, and healthy plate protein quality index were calculated. The associations of dietary variables with percentage total weight loss and percentage of fat-free mass loss relative to total weight loss were determined using linear regression. Logistic regression was used to estimate the odds of non-response (percentage total weight loss < 25%) and excessive fat-free mass loss (percentage of fat-free mass loss relative to total weight loss > 28%) based on dietary intakes. ResultsForty-six (31.5%) were non-responders, and 49 (33.6%) experienced excessive fat-free mass loss. The fully adjusted model showed a 0.75 decrease in percentage total weight loss per 5% carbohydrate increase (95% CI, –1.45 to –0.05). The odds of non-response were 53% lower per 5% increase in protein (95% CI, 0.23–0.94). Each 5-g higher intake of fat was associated with 0.29 higher percentage of fat-free mass loss relative to total weight loss (95% CI, 0.03–0.55). The odds of excessive fat-free mass loss were reduced by 5% per gram of fiber intake (95% CI, 0.90–0.99). Each 5% increment in energy intake from protein that was isocalorically substituted for either carbohydrate or fat was associated with lower odds of nonresponse. Macronutrient quality indices had no significant associations. ConclusionsAdherence to a high-protein, high-fiber diet after sleeve gastrectomy may enhance surgical success by improving total weight loss and preventing excessive fat-free mass loss.

Impact of weight loss and weight gain trajectories on body composition in a population at high risk of type 2 diabetes: A prospective cohort analysis.

In a primary care population at high risk of type 2 diabetes, 24-month weight change trajectories were used to investigate the impact of weight cycling on fat mass (FM) and fat-free mass (FFM). Cohort data from the Walking Away from Type 2 Diabetes trial was used, which recruited adults at-risk of type 2 diabetes from primary care in 2009/10. Annual weight change trajectories based on weight loss/gain of ≥5% were assessed over two 24-month periods. Body composition was measured by bioelectrical impedance analysis. Repeated measures were analysed using generalized estimating equations with participants contributing up to two 24-month observation periods. In total, 622 participants were included (average age = 63.6 years, body mass index = 32.0 kg/m2 , 35.4% women), contributing 1163 observations. Most observations (69.2%) were from those that maintained their body weight, with no change to FM or FFM. A minority (4.6% of observations) lost over 5% of body weight between baseline and 12 months, which was then regained between 12 and 24 months. These individuals regained FM to baseline levels, but lost 1.50 (0.66, 2.35) kg FFM, adjusted for confounders. In contrast, those that gained weight between baseline and 12 months but lost weight between 12 and 24 months (5.5% of observations) had a net gain in FM of 1.70 (0.27, 3.12) kg with no change to FFM. Weight cycling may be associated with a progressive loss in FFM and/or gain in FM in those with overweight and obesity at-risk of type 2 diabetes.

PROMISE: effect of protein supplementation on fat-free mass preservation after bariatric surgery, a randomized double-blind placebo-controlled trial

IntroductionProtein malnutrition after bariatric surgery is a severe complication and leads to significant morbidity. Previous studies have shown that protein intake and physical activity are the most important factors in the preservation of fat-free mass during weight loss. Low protein intake is very common in patients undergoing bariatric surgery despite dietary counseling. Protein powder supplements might help patients to achieve the protein intake recommendations after bariatric surgery and could therefore contribute to preserve fat-free mass. This double-blind randomized placebo-controlled intervention study aims to assess the effect of a daily consumed clear protein powder shake during the first 6 months after bariatric surgery on fat-free mass loss in the first 12 months after laparoscopic Roux-en-Y gastric bypass (LRYGB).Methods and analysisInclusion will take place at the outpatient clinic of the bariatric expertise center for obesity of the Maasstad Hospital. Patients will be randomly assigned to either the intervention or control group before surgery. The intervention group will receive a clear protein powder shake of 200 ml containing 20 g of whey protein dissolved in water which should be taken daily during the first 6 months after LRYGB on top of their normal postoperative diet. The control group will receive an isocaloric, clear, placebo shake containing maltodextrine. Postoperative rehabilitation and physiotherapeutical guidance will be standardized and similar in both groups. Also, both groups will receive the same dietary advice from specialized dieticians. The main study parameter is the percentage of fat-free mass loss 6 months after surgery, assessed by multi-frequency bioelectrical impedance analysis (MF-BIA).Ethics and disseminationThe protocol, version 2 (February 20, 2022) has been approved by the Medical Research Ethics Committees United (MEC-U) (NL 80414.100.22). The results of this study will be submitted to peer-reviewed journals.Trial registrationClinicalTrials.gov NCT05570474. Registered on October 5, 2022.

The impact of leucine supplementation on body composition and glucose tolerance following energy restriction: an 8-week RCT in adults at risk of the metabolic syndrome

BackgroundL-Leucine (Leu) supplementation may benefit fat-free mass (FFM) per se and glucose metabolism.ObjectivesTo determine whether Leu supplementation during energy restriction blunted the loss of FFM, enhanced the loss of fat mass (FM) and improved glucose tolerance.DesignThirty-seven adults, aged 20–65 years, with increased waist circumference and at least one other metabolic syndrome (MetS) component, were selected. We employed a two-arm parallel, double blind, randomized control trial (RCT) design. Participants were randomly assigned to an intervention group (leucine – 3 g/d) or placebo (lactose - 2.67 g/d), while following an individualised energy restricted diet for an 8-week period. Detailed body composition (DEXA), oral glucose tolerance test (OGTT), insulin and components of MetS were measured before and after the trial. Analysis of covariance (ANCOVA) assessed the effect of Leu on an intention-to-treat (ITT) principle. Bootstrapping method with 1000 bootstrap samples was used to derive parameter estimates, standard errors, p-values, and 95% confidence intervals for all outcomes.ResultsAdjusted for baseline values and other covariates, FFM (p = 0.045) and lean tissue mass (LTM) (p = 0.050) were significantly higher following Leu. These outcomes were modified by a significant treatment x sex interaction that indicated Leu had the greater effect in men. However, on adjustment for body composition changes, there was no difference in insulin sensitivity, oral glucose tolerance, or change in MetS components following Leu.ConclusionShort-term leucine supplementation during energy restriction resulted in a greater preservation of FFM and LTM particularly in men, but did not impact glucose metabolism.

Revisiting Resting Metabolic Rate: What is the Relation to Weight Fluctuations?

Despite the great progress in obesity-tackling strategies, a negative energy equilibrium between energy expenditure and energy intake remains the cornerstone in obesity management. The present review article aims to shed light on the complicated interrelations of resting metabolic rate to weight fluctuations. Energy expenditure depends on body composition and is highly affected by weight changes, exerting a significant role in subsequent weight regain and underlining the metabolic resistance that people with obesity face when dealing with weight maintenance. The main tissue involved in energy expenditure is fat-free mass, as opposed to fat mass, which exerts a substantially lower impact. Although people with obesity display higher energy expenditures than their lean counterparts, these decrease substantially in the setting of weight loss. Metabolic adaptation is the difference between measured and predicted RMR after weight loss, either via lifestyle modification or after obesity surgery. Plausible explanations for this include differences in body composition, with loss of fat-free mass playing a significant role. This becomes especially apparent in the setting of rapid and massive weight loss, as in the case of bariatric surgery. A better understanding of energy expenditure pathophysiology may aid in further enhancing weight loss and promoting weight maintenance in people with obesity.