Fat-free mass and resting metabolic rate are determinants of energy intake: implications for a theory of appetite control

Any explanation of appetite control should contain a description of physiological processes that could contribute a drive to eat alongside those that inhibit eating. However, such an undertaking was largely neglected until 15 years ago when a series of independent research programmes investigated the physiological roles of body composition and appetite. These outcomes demonstrated that fat-free mass (FFM), but not fat mass, was positively associated with objectively measured meal size and energy intake (EI). These findings have been accompanied by demonstrations that resting metabolic rate (RMR) is also positively associated with EI, with the influence of FFM largely mediated by RMR. These findings re-introduce the role of drive into models of appetite control and indicate how this can be integrated with processes of inhibition. The determinants of EI fit into an evolutionary perspective in which the energy demands of high metabolic rate organs and skeletal tissue constitute a need state underlying a tonic drive to eat. This approach should lead to the development of integrated models of appetite that include components of body composition (FFM) and energy expenditure (RMR) as tonic biological signals of appetite alongside other traditional tonic (adipose tissue derived) and episodic signals (gastrointestinal tract derived). This article is part of a discussion meeting issue 'Causes of obesity: theories, conjectures and evidence (Part I)'.

Nuts, Energy Balance and Body Weight

Over several decades, the health benefits of consuming nuts have been investigated, resulting in a large body of evidence that nuts can reduce the risk of chronic diseases. The consumption of nuts, being a higher-fat plant food, is restricted by some in order to minimize weight gain. In this review, we discuss several factors related to energy intake from nuts, including food matrix and its impact on digestibility, and the role of nuts in regulating appetite. We review the data from randomized controlled trials and observational studies conducted to examine the relationship between nut intake and body weight or body mass index. Consistently, the evidence from RCTs and observational cohorts indicates that higher nut consumption does not cause greater weight gain; rather, nuts may be beneficial for weight control and prevention of long-term weight gain. Multiple mechanisms likely contribute to these findings, including aspects of nut composition which affect nutrient and energy availability as well as satiety signaling.

Associations between high-metabolic rate organ masses and fasting hunger: A study using whole-body magnetic resonance imaging in healthy males

BACKGROUND

Fat-free mass (FFM) has been shown to be positively associated with hunger and energy intake, an association mediated by resting metabolic rate (RMR). However, FFM comprises a heterogeneous group of tissues with distinct metabolic rates, and it remains unknown how specific high-metabolic rate organs contribute to the degree of perceived hunger.

OBJECTIVE

To examine whether FFM and its anatomical components were associated with fasting hunger when assessed at the tissue-organ level.

DESIGN

Body composition (quantitative magnetic resonance and magnetic resonance imaging), RMR and whole-body glucose oxidation (indirect calorimetry), HOMA-index as a marker of insulin sensitivity, nitrogen balance and fasting hunger (visual analogue scales) were assessed in 21 healthy males (age = 25 ± 3y; BMI = 23.4 ± 2.1 kg/m²) after 3 days of controlled energy balance.

RESULTS

FFM (r_s = 0.39; p = 0.09), RMR (r_s = 0.52; p = 0.02) and skeletal muscle mass (r_s = 0.57; p = 0.04), but not fat mass (r_s = -0.01; p = 0.99), were positively associated with fasting hunger. The association between the combined mass of high-metabolic rate organs (i.e., brain, liver, kidneys and heart; r_s = 0.58; p = 0.006) and fasting hunger was stronger than with FFM as a uniform body component. The strongest individual association was between liver mass and fasting hunger (r_s = 0.51; p = 0.02). No associations were observed between glucose parameters, markers of insulin sensitivity and fasting hunger. The encephalic measure, an index of brain-to-body energy allocation, was negatively associated with fasting hunger (r_s = -0.51; p = 0.02).

CONCLUSIONS

Fasting hunger was more strongly associated with the combined mass of high-metabolic rate organs than with FFM as a uniform body component, highlighting the importance of integrating individual tissue-organ masses and their functional correlates into homeostatic models of human appetite. The association between liver mass and fasting hunger may reflect its role in ensuring the brain's basal energy needs are met.

Increases in physical activity are associated with a faster rate of weight loss during dietary energy restriction in women with overweight and obesity

This secondary analysis examined the influence of changes in physical activity (PA), sedentary time and energy expenditure (EE) during dietary energy restriction on the rate of weight loss (WL) and 1-year follow-up weight change in women with overweight/obesity.Measurements of body weight and composition (air-displacement plethysmography), resting metabolic rate (indirect calorimetry), total daily (TDEE) and activity EE (AEE), minutes of PA and sedentary time (PA monitor) were taken at baseline, after 2 weeks, after ≥5% WL or 12 weeks of continuous (25% daily energy deficit) or intermittent (75% daily energy deficit alternated with ad libitum day) energy restriction, and at 1-year post-WL. The rate of WL was calculated as total %WL/number of dieting weeks. Data from both groups were combined for analyses.Thirty-seven participants (age=35±10y; BMI=29.1±2.3kg/m2) completed the intervention (WL=-5.9±1.6%) and 18 returned at 1-year post-WL (weight change=+4.5±5.2%). Changes in sedentary time at 2 weeks were associated with the rate of WL during energy restriction (r=-0.38; p=0.03). Changes in total (r=0.54; p<0.01), light (r=0.43; p=0.01) and moderate-to-vigorous PA (r=0.55; p<0.01), sedentary time (r=-0.52; p<0.01), steps per day (r=0.39; p=0.02), TDEE (r=0.46; p<0.01) and AEE (r=0.51; p<0.01) during energy restriction were associated with the rate of WL. Changes in total (r=-0.50; p=0.04) and moderate-to-vigorous PA (r=-0.61; p=0.01) between post-WL and follow-up were associated with 1-year weight change (r=-0.51; p=0.04).These findings highlight that PA and sedentary time could act as modifiable behavioural targets to promote better weight outcomes during dietary energy restriction and/or weight maintenance.

Free-Living Energy Balance Behaviors Are Associated With Greater Weight Loss During a Weight Loss Program

Introduction: Free-living movement (physical activity [PA] and sedentary behavior [SB]) and eating behaviors (energy intake [EI] and food choice) affect energy balance and therefore have the potential to influence weight loss (WL). This study explored whether free-living movement and/or eating behaviors measured early (week 3) in a 14-week WL programme or their change during the intervention are associated with WL in women. Methods: In the study, 80 women (M ± SD age: 42.0 ± 12.4 years) with overweight or obesity [body mass index (BMI): 34.08 ± 3.62 kg/m²] completed a 14 week WL program focused primarily on diet (commercial or self-led). Body mass (BM) was measured at baseline, and again during week 2 and 14 along with body composition. Free-living movement (SenseWear Armband) and eating behavior (weighed food diaries) were measured for 1 week during week 3 and 12. Hierarchical multiple regression analyses examined whether early and early-late change in free-living movement and eating behavior were associated with WL. The differences in behavior between clinically significant weight losers (CWL; ≥5% WL) and non-clinically significant weight losers (NWL; ≤ 3% WL) were compared. Results: The energy density of food consumed [β = 0.45, p < 0.001] and vigorous PA [β = -0.30, p < 0.001] early in the intervention (regression model 1) and early-late change in light PA [β = -0.81 p < 0.001], moderate PA [β = -1.17 p < 0.001], vigorous PA [β = -0.49, p < 0.001], total energy expenditure (EE) [β = 1.84, p < 0.001], and energy density of food consumed [β = 0.27, p = 0.01] (regression model 2) significantly predicted percentage change in BM. Early in the intervention, CWL consumed less energy dense foods than NWL [p = 0.03]. CWL showed a small but significant increase in vigorous PA, whereas NWL showed a slight decrease in PA [p = 0.04]. Conclusion: Both early and early-late change in free-living movement and eating behaviors during a 14 week WL program are predictors of WL. These findings demonstrate that specific behaviors that contribute to greater EE (e.g., vigorous PA) and lower EI (e.g., less energy-dense foods) are related to greater WL outcomes. Interventions targeting these behaviors can be expected to increase the effectiveness of WL programs.

Effective behavior change techniques to promote physical activity in adults with overweight or obesity: A systematic review and meta-analysis

Multicomponent behavior change interventions are typically used in weight management, but results are largely heterogeneous and modest. Determining which techniques (behavior change technique [BCTs]) are more effective in changing behavior is thus required. This study aimed to identify the most effective BCTs for increasing physical activity (PA) in digital and face-to-face behavior change interventions in adults with overweight/obesity. Four databases were searched for eligible studies until October 2019. BCTs were coded using BCTTv1 and MBCT taxonomies. Sixty-two RCTs were included. Meta-regressions were performed to explore BCTs' moderating role. Five BCTs showed significant moderator effects on PA in digital interventions: goal setting behavior, goal setting outcome, graded tasks, social incentive, and self-monitoring of behavior (adjusted R² 's = 0.15-0.51). One BCT showed significant moderator effects on PA in face-to-face interventions, behavioral practice and rehearsal (adjusted R²  = 0.22). Multivariate and sensitivity analysis generally led to similar findings. Effective BCTs for increasing PA in adults with overweight/obesity in digital and face-to-face interventions seem to differ. Evidence suggests that using goal setting, social incentive, and graded tasks might help improve PA in digital interventions while avoiding inconsistent self-monitoring of behavior. In face-to-face interventions, prompting behavioral practice and rehearsal might lead to better PA outcomes. Still, further studies are needed. Implications of the current findings are discussed.

Effects of oral lubrication on satiety, satiation and salivary biomarkers in model foods: A pilot study

With a dramatic increase in overweight and population with obesity over the last decades, there is an imminent need to tackle this issue using novel strategies. Addressing obesity issues by generating satiety in food to reduce energy intake has been one of those prominent strategies and often textural interventions have been used to generate satiety, specifically in short-term trials. This study aimed to investigate the role of preloads varying in their oral lubricating properties on appetite sensations, food intake, salivary friction and concentration of salivary biomarkers (proteins, α-amylase and mucins) in collected human saliva (n = 17 healthy participants). The preloads were model foods (flavoured hydrogels) either high or low in their lubricating properties, assessed both by instrumental and sensorial measurements. The results showed that hunger and desire to eat decreased immediately after preload and remained decreased for 10 and 20 min, respectively, after preload in the high lubricating condition compared to control (all p < 0.05). Fullness increased immediately after preload and remained increased for 10 and 20 min, respectively, after preload in high lubricating condition compared to control (p < 0.05). However, after controlling the values for baseline, such significant effect of the intervention did not exist anymore. Only the effect of time is observed. Consuming high lubricating hydrogels showed no effect on food intake and salivary biomarkers in this pilot study. Salivary lubrication correlated with feeling of fullness. Considering the issue of large time-interval (30 min) between preload and next meal in this study, it is worthwhile investigating the immediate effects of oral lubrication on appetite control, food intake and salivary biomarkers.

Postprandial glycaemic dips predict appetite and energy intake in healthy individuals

Understanding how to modulate appetite in humans is key to developing successful weight loss interventions. Here, we showed that postprandial glucose dips 2-3 h after a meal are a better predictor of postprandial self-reported hunger and subsequent energy intake than peak glucose at 0-2 h and glucose incremental area under the blood glucose curve at 0-2 h. We explore the links among postprandial glucose, appetite and subsequent energy intake in 1,070 participants from a UK exploratory and US validation cohort, who consumed 8,624 standardized meals followed by 71,715 ad libitum meals, using continuous glucose monitors to record postprandial glycaemia. For participants eating each of the standardized meals, the average postprandial glucose dip at 2-3 h relative to baseline level predicted an increase in hunger at 2-3 h (r = 0.16, P < 0.001), shorter time until next meal (r = -0.14, P < 0.001), greater energy intake at 3-4 h (r = 0.19, P < 0.001) and greater energy intake at 24 h (r = 0.27, P < 0.001). Results were directionally consistent in the US validation cohort. These data provide a quantitative assessment of the relevance of postprandial glycaemia in appetite and energy intake modulation.

Effects of oral semaglutide on energy intake, food preference, appetite, control of eating and body weight in subjects with type 2 diabetes

AIM

To evaluate the effect of oral semaglutide on energy intake and appetite in subjects with type 2 diabetes (T2D).

MATERIALS AND METHODS

In this randomized, double-blind, placebo-controlled, two-period cross-over trial, 15 subjects with T2D received 12 weeks of treatment with once-daily oral semaglutide (4-week dose escalation from 3 to 7 to 14 mg) followed by placebo, or vice versa. Energy intake was measured during an ad libitum lunch, evening meal and snack box after a standard breakfast. Appetite ratings were measured using a visual analogue scale after standard and fat-rich breakfasts. Other assessments included eating and craving control (using the Control of Eating Questionnaire), and changes in body weight and composition.

RESULTS

Following a standard breakfast, total daily ad libitum energy intake was significantly lower (38.9%) with oral semaglutide versus placebo in 13 evaluable subjects (estimated treatment difference, -5096.0 kJ; 95% CI -7000.0, -3192.1; P = .0001). After a fat-rich breakfast, there were significant differences in favour of oral semaglutide versus placebo for measures of satiety, hunger and for overall appetite score, with no significant differences following a standard breakfast. Fewer food cravings and better eating control were seen with oral semaglutide versus placebo. Overall, mean body weight decreased by 2.7 kg with oral semaglutide and 0.1 kg with placebo, mostly attributable to body fat mass loss.

CONCLUSION

After 12 weeks of treatment, ad libitum energy intake was lower with oral semaglutide versus placebo, resulting in reduced body fat mass, and was associated with increased satiety and fullness after a fat-rich breakfast, and improved eating control.

TRIAL REGISTRATION NUMBER

NCT02773381.

Body Fatness Influences Associations of Body Composition and Energy Expenditure with Energy Intake in Healthy Women

OBJECTIVE

This study aimed to investigate the influence of body fatness on the associations of body composition and energy expenditure (EE) with energy intake (EI).

METHODS

Data from 93 women (BMI = 25.5 [SD 4.2] kg/m² ) recruited for two studies (Study 1, n = 48, BMI = 25.0-34.9 kg/m² ; Study 2, n = 45, BMI = 18.5-24.9 kg/m² ) were examined. Body composition, resting metabolic rate (RMR), and test meal EI were assessed during a laboratory probe day. Physical activity, total daily EE (TDEE), and self-reported free-living 24-hour EI were collected during 7 days.

RESULTS

In the whole sample, fat-free mass (r = 0.45; P < 0.001), RMR (r = 0.41; P < 0.001), and TDEE (r = 0.39; P < 0.001), but not fat mass (r = 0.17; P = 0.11), were positively associated with free-living 24-hour EI. Body fat percentage moderated the associations of RMR (β = -1.88; P = 0.02) and TDEE (β = -1.91; P = 0.03) with mean free-living 24-hour EI. Fat mass was negatively associated with test meal EI only in the leaner group (r = -0.43; P = 0.004), and a weak nonlinear association was observed in the whole sample (r²  = 0.092; P = 0.04).

CONCLUSIONS

Body fat percentage appears to moderate the associations between EE and daily EI. Furthermore, the negative association between fat mass and test meal EI observed in leaner individuals was absent in those with higher body fatness. Therefore, higher levels of body fatness may weaken the coupling between EE and EI.

Exercise Training Reduces Reward for High-Fat Food in Adults with Overweight/Obesity

PURPOSE

There is increasing evidence that exercise training may facilitate weight management via improvements in homeostatic appetite control, but little is known about how exercise training affects food reward and susceptibility to overeating.

METHODS

This study examined changes in food reward and eating behavior traits after a supervised 12-wk exercise intervention (10.5 MJ·wk) in inactive individuals with overweight/obesity (exercisers; n = 46, 16 men/30 women; mean (SD) body mass index, 30.6 (3.8) kg·m; and mean (SD) age, 43.2 (7.5) yr) compared with nonexercising controls (n = 15; 6 men/9 women; mean (SD) body mass index, 31.4 (3.7) kg·m; and mean (SD) age, 41.4 (10.7) yr). Liking and wanting scores for high-fat relative to low-fat foods were assessed with the Leeds Food Preference Questionnaire before and after consumption of an isoenergetic high-fat or high-carbohydrate lunch. Eating behavior traits were assessed using the Three-Factor Eating Questionnaire and Binge Eating Scale.

RESULTS

A week-group interaction indicated that wanting scores decreased from baseline to postintervention in exercisers only (M[INCREMENT]Pre-Post = -4.1, P = 0.03, ηp = 0.09, 95% confidence interval [CI], -7.8 to -0.4), but there was no exercise effect on liking. There was also a week-group interaction for binge eating, which decreased in exercisers only (M[INCREMENT]Pre-Post = -1.5, P = 0.01, ηp = 0.11; 95% CI, -2.7 to -0.4). A small reduction in disinhibition was also apparent in exercisers (M[INCREMENT]Pre-Post = -0.7, P = 0.02, ηp = 0.10; 95% CI, -1.3 to -0.1).

CONCLUSIONS

This study showed that 12 wk of exercise training reduced wanting scores for high-fat foods and trait markers of overeating in individuals with overweight/obesity compared with nonexercising controls. Further research is needed to elucidate the mechanisms behind these exercise-induced changes in food reward.

Matched Weight Loss Through Intermittent or Continuous Energy Restriction Does Not Lead To Compensatory Increases in Appetite and Eating Behavior in a Randomized Controlled Trial in Women with Overweight and Obesity

BACKGROUND

Continuous energy restriction (CER) is purported to be problematic because of reductions in fat-free mass (FFM), compensatory motivation to overeat, and weakened satiety. Intermittent energy restriction (IER) is an alternative behavioral weight loss (WL) strategy that may mitigate some of these limitations.

OBJECTIVE

The objective of the DIVA study was to compare the effects of CER and IER on appetite when the degree of WL (≥5%) is matched.

METHODS

Women with overweight/obesity (BMI 25.0-34.9 kg/m2; age 18-55 y) were recruited for this controlled-feeding RCT via CER (25% daily energy restriction) or IER (alternating ad libitum and 75% energy restriction days). Probe days were conducted at baseline and post-intervention to assess body composition, ad libitum energy intake and subjective appetite in response to a fixed-energy breakfast, and eating behavior traits. After baseline measurements, participants were allocated to CER (n = 22) or IER (n = 24). Per protocol analyses (≥5% WL within 12 wk) were conducted with use of repeated measures ANOVA.

RESULTS

Thirty of 37 completers reached ≥5% WL [CER (n = 18): 6.3 ± 0.8% in 57 ± 16 d, IER (n = 12): 6.6 ± 1.1% in 67 ± 13 d; % WL P = 0.43 and days P = 0.10]. Fat mass [-3.9 (95% CI: -4.3, -3.4) kg] and FFM [-1.3 (95% CI: -1.6, -1.0) kg] were reduced post-WL (P < 0.001), with no group differences. Self-selected meal size decreased post-WL in CER (P = 0.03) but not in IER (P = 0.19). Hunger AUC decreased post-WL (P < 0.05), with no group differences. Satiety quotient remained unchanged and was similar in both groups. Both interventions improved dietary restraint, craving control, susceptibility to hunger, and binge eating (P < 0.001).

CONCLUSIONS

Controlled ≥5% WL via CER or IER did not differentially affect changes in body composition, reductions in hunger, and improvements in eating behavior traits. This suggests that neither CER nor IER lead to compensatory adaptations in appetite in women with overweight/obesity. This trial was registered at clinicaltrials.gov as NCT03447600.

Disturbed Appetite Patterns and Nutrient Intake in Peritoneal Dialysis Patients

Objective

Malnutrition is common among peritoneal dialysis (PD) patients. Reduced nutrient intake contributes to this. It has long been assumed that this reflects disturbed appetite. We set out to define the appetite profiles of a group of PD patients using a novel technique.

Design

Prospective, cross-sectional comparison of PD patients versus controls.

Setting

Teaching hospital dialysis unit.

Patients

39 PD patients and 42 healthy controls.

Intervention

Visual analog ratings were recorded at hourly intervals to generate daily profiles for hunger and fullness. Summary statistics were generated to compare the groups. Food intake was measured using 3-day dietary records.

Main Outcome Measures

Hunger and fullness profiles. Derived hunger and fullness scores.

Results

Controls demonstrated peaks of hunger before mealtimes, with fullness scores peaking after meals. The PD profiles had much reduced premeal hunger peaks. A postmeal reduction in hunger was evident, but the rest of the trace was flat. The PD fullness profile was also flatter than in the controls. Mean scores were similar despite the marked discrepancy in the profiles. The PD group had lower peak hunger and less diurnal variability in their hunger scores. They also demonstrated much less change in fullness rating around mealtimes, while the mean and peak fullness scores were little different. The reported nutrient intake was significantly lower for PD.

Conclusion

The data suggest that PD patients normalize their mean appetite perception at a lower level of nutrient intake than controls, suggesting that patient-reported appetite may be misleading in clinical practice. There is a loss of the usual daily variation for the PD group, which may contribute to their reduced food intake. The technique described here could be used to assess the impact of interventions upon the abnormal PD appetite profile.

Is reducing appetite beneficial for body weight management in the context of overweight and obesity? A systematic review and meta-analysis from clinical trials assessing body weight management after exposure to satiety enhancing and/or hunger reducing products

This review aims to investigate whether interventions that enhance satiety and/or reduce hunger lead to beneficial effects on body weight management in the context of overweight and obesity. A comprehensive review protocol was prepared before conducting a systematic search in PubMed identifying 517 papers with 12 meeting the inclusion criteria. A thorough risk of bias assessment was performed based on the Cochrane collaboration's tool for assessing risk of bias. Based on a meta-analysis, the average of 75 subjects exposed to satiety enhancing and/or hunger reducing foods during more than 8 weeks coincidently reduced their body weight by 3.60 (1.05; 6.15) kg (mean (95% confidence interval)) more compared with controls. Two studies analysed whether individual reductions in appetite were associated with body weight. Decreased ad libitum energy intake after exposure to the satiety enhancing and/or hunger reducing interventions explained 58% (P < 0.001) and 23% (P < 0.001) of the variations in the subsequent weight losses over 12 and 8 weeks, respectively. Robust acute effects on appetite were found equally likely to be linked to improved body weight management as sustained effects. Satiety enhancing and/or hunger reducing interventions are supported to improve body weight management, but studies specifically designed to demonstrate a causal link remain needed.

Semaglutide as a promising antiobesity drug

Semaglutide is a glucagon-like peptide-1 receptor agonist (GLP-1 RA) with a long elimination half-life, allowing subcutaneous (sc) administration once per week. Both the European Medicines Agency (EMA) and the Food and Drug Administration (FDA) recently approved once-weekly sc semaglutide for the treatment of type 2 diabetes mellitus (T2DM). The weight loss efficacy of once-weekly sc semaglutide appears to be superior compared with the other once-weekly GLP-1 RAs in patients with T2DM. Semaglutide was recently evaluated as an antiobesity drug in a phase II dose-finding trial, which demonstrated superior weight loss efficacy of once daily sc semaglutide compared with both placebo and once daily 3.0 mg liraglutide in patients with obesity but without T2DM. The magnitude of semaglutide-induced weight loss in this study exceeded the criteria of both the EMA and FDA for antiobesity drugs, and there were no safety concerns, indicating the eligibility of once daily sc semaglutide as a future antiobesity drug.

Changes in food reward during weight management interventions - a systematic review

BACKGROUND

Does food reward increase or decrease during weight management attempts? Excessive food intake is the main behavioural determinant of obesity; therefore, a better understanding of food reward and its relationship with food intake and weight outcomes could contribute to more effective weight management solutions.

METHODS

This systematic review assessed the role of changes in food reward (directly or indirectly measured) during weight management interventions. Four databases were searched for articles published until April 2018 involving weight management interventions (all types and designs) in healthy adults with overweight or obesity.

RESULTS

Of 239 full-text articles assessed, 17 longitudinal studies were included. Twelve studies reported a significant change in food reward over time. When compared with control interventions, dietary, pharmacological, behavioural and cognitive interventions were effective in decreasing liking and/or wanting for high-energy food using a range of methodologies to assess food reward. Three studies reported that decreased food reward was associated with improved weight management outcomes.

CONCLUSION

Food reward appears to decrease rather than increase during weight management interventions. Future studies specifically targeting the hedonic aspects of food intake (liking/wanting) are needed to gain a better understanding of how to uncouple the obesogenic relationship between food reward and overeating.

Structured, aerobic exercise reduces fat mass and is partially compensated through energy intake but not energy expenditure in women

BACKGROUND

Exercise-induced weight loss is often less than expected and highly variable in men and women. Behavioural compensation for the exercise-induced energy deficit could be through energy intake (EI), non-exercise physical activity (NEPA) or sedentary behaviour (SB). We investigated this issue in women.

METHODS

Twenty-four overweight [body mass index (BMI) M = 27.9 kg/m², SD = 2.7] women [age M = 33.1 years, SD = 11.7] completed 12-weeks of supervised exercise (5×500kcal per week) in a non-randomised, pre-post intervention study. Body mass (BM), waist circumference (WC), body composition, resting metabolic rate (RMR), total daily EI, individual meals, appetite sensations and appetite-related peptides were measured at baseline (week 0) and post-intervention (week 12). Free-living physical activity (PA) and SB were measured (SenseWear) at baseline, week 1 and 10 of the exercise intervention, and at post-intervention (week 13).

RESULTS

Following the 12-week exercise intervention BM [p = .04], BMI [p = .035], WC [p < .001] and fat mass (FM) [p = .003] were significantly reduced, and fat-free mass (FFM) significantly increased [p = .003]. Total [p = .028], ad libitum [p = .03] and snack box EI [p = .048] were significantly increased and this was accompanied by an increase in hunger [p = .01] and a decrease in fullness [p = .03] before meals. The peptides did not explain changes in appetite [p > .05]. There was no compensatory reduction in NEPA [p > .05] and no increase in SB, rather there was a decrease in SB during the exercise intervention [p = .03].

CONCLUSIONS

Twelve-weeks of supervised aerobic exercise resulted in a significant reduction in FM and an increase in FFM. Exercise increased hunger and EI which only partially compensated for the increase in energy expenditure. There was no evidence for a compensatory reduction in NEPA or an increase in SB. Dietary intervention, as an adjunct to exercise, may offset the compensatory increase in EI and result in a greater reduction in BM.

TRIAL REGISTRATION

Our trial was retrospectively registered on the International Standard Randomised Controlled Trials Registry (ISRCTN78021668, 27th September 2016) and can be found here: https://doi.org/10.1186/ISRCTN78021668.

Disentangling the relationship between sedentariness and obesity: Activity intensity, but not sitting posture, is associated with adiposity in women

BACKGROUND

The relationship between free-living sedentary behaviour (SB) and obesity is unclear. Studies may arrive at disparate conclusions because of inconsistencies and limitations when defining and measuring free-living SB. The aim of this cross-sectional study was to examine whether the relationship between SB and adiposity differed depending on the way SB was operationally defined and objectively measured.

METHODS

Sixty-three female participants aged 37.1 years (SD = 13.6) with a body mass index (BMI) of 29.6 kg/m² (SD = 4.7) had their body composition measured (BodPod, Concord, CA) then were continuously monitored for 5-7 days with the SenseWear Armband (SWA; sleep and activity intensity) and the activPAL (AP; posture). Data from both activity monitors were analysed separately and integrated resulting in a third measure of SB (activity intensity and posture; SED^INT). SB outputs were compared according to week or weekend day averages then correlated against body composition parameters after adjusting for moderate-to-vigorous physical activity (MVPA).

RESULTS

SED^SWA resulted in the most sedentary time 11.74 h/day (SD = 1.60), followed by SED^AP 10.16 h/day (SD = 1.75) and SED^INT 9.10 h/day (SD = 1.67). There was a significant positive association between SED^SWA and body mass [r(61) = 0.29, p = .02], BMI [r (61) = 0.33, p = .009] and fat mass [r(61) = 0.32, p = .01]. SED^AP and SED^INT were not associated with any of the indices of adiposity. Correlations between SB and adiposity were non-significant when controlling for MVPA.

CONCLUSIONS

The relationship between SB and adiposity differed depending on how SB was operationally defined and measured, and was dependent on MVPA. The definition of SB based on a sitting posture (SED^AP) was not strongly related to body fat, whereas the accumulation of any behaviour (sitting or standing) with an intensity of <1.5 METs (SED^SWA) (offset by the presence of MVPA) was positively associated with indices of adiposity. These data suggest that the postural element of SB (sitting) is not sufficient for the accumulation of adiposity, rather activities requiring low EE (<1.5 METs) and the absence of MVPA, regardless of posture, are associated with higher fat mass.

Does Habitual Physical Activity Increase the Sensitivity of the Appetite Control System? A Systematic Review

Background

It has been proposed that habitual physical activity improves appetite control; however, the evidence has never been systematically reviewed.

Objective

To examine whether appetite control (e.g. subjective appetite, appetite-related peptides, food intake) differs according to levels of physical activity.

Data Sources

Medline, Embase and SPORTDiscus were searched for articles published between 1996 and 2015, using keywords pertaining to physical activity, appetite, food intake and appetite-related peptides.

Study Selection

Articles were included if they involved healthy non-smoking adults (aged 18–64 years) participating in cross-sectional studies examining appetite control in active and inactive individuals; or before and after exercise training in previously inactive individuals.

Study Appraisal and Synthesis

Of 77 full-text articles assessed, 28 studies (14 cross-sectional; 14 exercise training) met the inclusion criteria.

Results

Appetite sensations and absolute energy intake did not differ consistently across studies. Active individuals had a greater ability to compensate for high-energy preloads through reductions in energy intake, in comparison with inactive controls. When physical activity level was graded across cross-sectional studies (low, medium, high, very high), a significant curvilinear effect on energy intake (z-scores) was observed.

Limitations

Methodological issues existed concerning the small number of studies, lack of objective quantification of food intake, and various definitions used to define active and inactive individuals.

Conclusion

Habitually active individuals showed improved compensation for the energy density of foods, but no consistent differences in appetite or absolute energy intake, in comparison with inactive individuals. This review supports a J-shaped relationship between physical activity level and energy intake. Further studies are required to confirm these findings.

PROSPERO Registration Number

CRD42015019696

Electronic supplementary material

The online version of this article (doi:10.1007/s40279-016-0518-9) contains supplementary material, which is available to authorized users.

Semaglutide improves postprandial glucose and lipid metabolism, and delays first-hour gastric emptying in subjects with obesity

AIM

To investigate the effects of semaglutide on fasting and postprandial glucose and lipid responses, and on gastric emptying.

MATERIALS AND METHODS

This was a randomized, double-blind, placebo-controlled, 2-period, crossover trial. Subjects with obesity (N = 30) received once-weekly subcutaneous semaglutide, dose-escalated to 1.0 mg, or placebo. After each 12-week treatment period, glucose and lipid metabolism were assessed before and after standardized meals. Gastric emptying (paracetamol absorption test) and peptide YY (PYY) response were also assessed.

RESULTS

Semaglutide treatment significantly lowered fasting concentrations of glucose and glucagon, and increased insulin vs placebo (estimated treatment ratio: 0.95 [95% confidence interval: 0.91, 0.98]; 0.86 [0.75, 0.98]; 1.45 [1.20, 1.75], respectively). Postprandial glucose metabolism significantly improved with semaglutide vs placebo (incremental area under the curve 0 to 5 hours [iAUC0-5h ]; estimated treatment difference: glucose -1.34 mmol h/L [-2.42, -0.27]; insulin -921 pmol h/L [-1461, -381]; C-peptide -1.42 nmol h/L [-2.33, -0.51]). Fasting and postprandial lipid metabolism improved with semaglutide vs placebo. First-hour gastric emptying after the meal was delayed with semaglutide vs placebo (AUC0-1h ; estimated treatment ratio: 0.73 [0.61, 0.87]); this may have contributed to the lower postprandial glucose increase in semaglutide-treated subjects. Overall gastric emptying (AUC0-5h ) was not statistically different between treatments. Fasting and postprandial PYY responses were significantly lower with semaglutide vs placebo (P = .0397 and P = .0097, respectively).

CONCLUSION

Semaglutide improved fasting and postprandial glucose and lipid metabolism. Overall gastric emptying was similar to that with placebo; however, the observed first-hour delay with semaglutide may contribute to a slower entry of glucose into the circulation.

Weight loss decreases self-reported appetite and alters food preferences in overweight and obese adults: Observational data from the DiOGenes study

People with obesity often struggle to maintain their weight loss after a weight loss period. Furthermore, the effect of weight loss on appetite and food preferences remains unclear. Hence this study investigated the effect of weight loss on subjective appetite and food preferences in healthy, overweight and obese volunteers. A subgroup of adult participants (n = 123) from the Diet Obesity and Genes (DiOGenes) study (subgroup A) was recruited from across six European countries. Participants lost ≥8% of initial body weight during an 8-week low calorie diet (LCD). Subjective appetite and food preferences were measured before and after the LCD, in response to a standardized meal test, using visual analogue rating scales (VAS) and the Leeds Food Choice Questionnaire (FCQ). After the LCD, participants reported increased fullness (p < 0.05), decreased desire to eat (p < 0.05) and decreased prospective consumption (p < 0.05) after consuming the test meal. An interaction effect (visit x time) was found for hunger ratings (p < 0.05). Area under the curve (AUC) for hunger, desire to eat and prospective consumption was decreased by 18.1%, 20.2% and 21.1% respectively whereas AUC for fullness increased by 13.9%. Preference for low-energy products measured by the Food Preference Checklist (FPC) decreased by 1.9% before the test meal and by 13.5% after the test meal (p < 0.05). High-carbohydrate and high-fat preference decreased by 11.4% and 16.2% before the test meal and by 17.4% and 22.7% after the meal (p < 0.05). No other effects were observed. These results suggest that LCD induced weight loss decreases the appetite perceptions of overweight volunteers whilst decreasing their preference for high-fat-, high-carbohydrate-, and low-energy products.

High Habitual Physical Activity Improves Acute Energy Compensation in Nonobese Adults

PURPOSE

Evidence suggests that homeostatic satiety signaling is enhanced with higher levels of physical activity (PA), with active individuals demonstrating an improved ability to compensate for previous energy intake (EI). However, prior studies lacked objective assessment of both PA level and EI. This study examined the effect of objectively measured PA level on homeostatic (energy compensation) and hedonic (liking and wanting) responses to high-energy (HEP), low-energy (LEP), and control preloads.

METHODS

Thirty-four nonobese individuals were grouped by tertiles of accelerometry-measured habitual moderate-to-vigorous PA (low, LoMVPA; moderate, ModMVPA; high, HiMVPA), similar in age, sex, and body mass index. After a preliminary assessment, EI (fixed-energy breakfast and ad libitum lunch, dinner, and evening snack box meals) was determined for three probe meal days in which preloads varying in energy content (HEP, 699 kcal; LEP, 258 kcal; control, 0 kcal) were consumed before the lunch meal. Liking and wanting were assessed before and after preload consumption (Leeds Food Preference Questionnaire), and appetite ratings were taken throughout the day.

RESULTS

Relative to control, EI at lunch was reduced to a greater extent after consumption of HEP compared with LEP in ModMVPA (P < 0.01) and HiMVPA (P = 0.01) but not LoMVPA (P = 0.59), reflecting more accurate energy compensation in HiMVPA and ModMVPA. There were no effects on cumulative EI after preload consumption of (lunch, dinner, and snack box combined). HEP led to a greater suppression of hunger, liking, and wanting compared with LEP in all MVPA tertiles.

CONCLUSIONS

Nonobese individuals with lower levels of measured PA were insensitive to the nutritional manipulation of the preloads, suggesting a weaker satiety response to food. This study provides objective evidence that higher habitual PA improves acute homeostatic appetite control.

A novel integrative procedure for identifying and integrating three-dimensions of objectively measured free-living sedentary behaviour

BACKGROUND

The widely accepted definition of sedentary behaviour [SB] refers to any waking behaviour characterized by an energy expenditure ≤1.5 metabolic equivalents [METs] while in a sitting or reclining posture. At present, there is no single field-based device which objectively measures sleep, posture and activity intensity simultaneously. The aim of this study was to develop a novel integrative procedure [INT] to combine information from two validated activity monitors on sleep, activity intensity and posture, the three key dimensions of SB.

METHODS

Participants in this analysis were initially recruited from a series of three studies conducted between December 2014 and June 2016 at the University of Leeds. Sixty-three female participants aged 37.1 (13.6) years with a body mass index of 29.6 (4.7) kg/m² were continuously monitored for 5-7 days with the SenseWear Armband [SWA] (sleep and activity intensity) and the activPAL [AP] (posture). Data from both activity monitors were analysed separately and integrated resulting in three measures of sedentary time. Differences in Sedentary time between the three measurement methods were assessed as well as how well the three measures correlated.

RESULTS

The three measures of sedentary time were positively correlated, with the weakest relationship between SED^SWA (awake and <1.5 METs) and SED^AP (awake and sitting/lying posture) [r(61) = .37,p = .003], followed by SED^SWA and SED^INT (awake, <1.5 METs and sitting/lying posture) [r(61) = .58,p < .001], and the strongest relationship was between SED^AP and SED^INT [r(61) = .91,p < .001]. There was a significant difference between the three measures of sedentary time [F(1.18,73.15) = 104.70,p < .001]. Post-hoc tests revealed all three methods differed significantly from each other [p < .001]. SED^SWA resulted in the most sedentary time 11.74 (1.60) hours/day, followed by SED^AP 10.16 (1.75) hours/day, and SED^INT 9.10 (1.67) hours/day. Weekday and weekend day sedentary time did not differ for any of the measurement methods [p = .04-.25].

CONCLUSION

Information from two validated activity monitors was combined to obtain an objective measure of free-living SB based on posture and activity intensity during waking hours. The amount of sedentary time accumulated varied according to the definition of SB and its measurement. The novel data integration and processing procedures presented in this paper represents an opportunity to investigate whether different components of SB are differentially related to health end points.

Effects of once-weekly semaglutide on appetite, energy intake, control of eating, food preference and body weight in subjects with obesity

AIM

The aim of this trial was to investigate the mechanism of action for body weight loss with semaglutide.

MATERIALS AND METHODS

This randomised, double-blind, placebo-controlled, two-period crossover trial investigated the effects of 12 weeks of treatment with once-weekly subcutaneous semaglutide, dose-escalated to 1.0 mg, in 30 subjects with obesity. Ad libitum energy intake, ratings of appetite, thirst, nausea and well-being, control of eating, food preference, resting metabolic rate, body weight and body composition were assessed.

RESULTS

After a standardised breakfast, semaglutide, compared with placebo, led to a lower ad libitum energy intake during lunch (-1255 kJ; P  < .0001) and during the subsequent evening meal ( P  = .0401) and snacks ( P  = .0034), resulting in a 24% reduction in total energy intake across all ad libitum meals throughout the day (-3036 kJ; P  < .0001). Fasting overall appetite suppression scores were improved with semaglutide vs placebo, while nausea ratings were similar. Semaglutide was associated with less hunger and food cravings, better control of eating and a lower preference for high-fat foods. Resting metabolic rate, adjusted for lean body mass, did not differ between treatments. Semaglutide led to a reduction from baseline in mean body weight of 5.0 kg, predominantly from body fat mass.

CONCLUSION

After 12 weeks of treatment, ad libitum energy intake was substantially lower with semaglutide vs placebo with a corresponding loss of body weight observed with semaglutide. In addition to reduced energy intake, likely mechanisms for semaglutide-induced weight loss included less appetite and food cravings, better control of eating and lower relative preference for fatty, energy-dense foods.

Impact of physical activity level and dietary fat content on passive overconsumption of energy in non-obese adults

Background

Passive overconsumption is the increase in energy intake driven by the high-fat energy-dense food environment. This can be explained in part because dietary fat has a weaker effect on satiation (i.e. process that terminates feeding). Habitually active individuals show improved satiety (i.e. process involved in post-meal suppression of hunger) but any improvement in satiation is unknown. Here we examined whether habitual physical activity mitigates passive overconsumption through enhanced satiation in response to a high-fat meal.

Methods

Twenty-one non-obese individuals with high levels of physical activity (HiPA) and 19 individuals with low levels of physical activity (LoPA) matched for body mass index (mean = 22.8 kg/m²) were recruited. Passive overconsumption was assessed by comparing ad libitum energy intake from covertly manipulated high-fat (HFAT; 50% fat) or high-carbohydrate (HCHO; 70% carbohydrate) meals in a randomized crossover design. Habitual physical activity was assessed using SenseWear accelerometers (SWA). Body composition, resting metabolic rate, eating behaviour traits, fasting appetite-related peptides and hedonic food reward were also measured.

Results

In the whole sample, passive overconsumption was observed with greater energy intake at HFAT compared to HCHO (p < 0.01), without any differences between activity groups (p > 0.05). SWA confirmed that HiPA were more active than LoPA (p < 0.01). HiPA had lower body fat and greater fat-free mass than LoPA (p < 0.05 for both) but did not differ in resting metabolic rate, eating behaviour traits, appetite-related peptides or food reward (p > 0.05 for all).

Conclusions

Non-obese individuals with high or low physical activity levels but matched for BMI showed similar susceptibility to passive overconsumption when consuming an ad libitum high-fat compared to a high-carbohydrate meal. This occurred despite increased total daily energy expenditure and improved body composition in HiPA. Greater differences in body composition and/or physical activity levels may be required to impact on satiation.

Electronic supplementary material

The online version of this article (doi:10.1186/s12966-017-0473-3) contains supplementary material, which is available to authorized users.

Associations among sedentary and active behaviours, body fat and appetite dysregulation: investigating the myth of physical inactivity and obesity

BACKGROUND

There is considerable disagreement about the association between free-living physical activity (PA) and sedentary behaviour and obesity. Moreover studies frequently do not include measures that could mediate between PA and adiposity. The present study used a validated instrument for continuous tracking of sedentary and active behaviours as part of habitual daily living, together with measures of energy expenditure, body composition and appetite dysregulation. This cross-sectional study tested the relationship between inactivity and obesity.

METHODS

71 participants (81.7% women) aged 37.4 years (±14) with a body mass index of 29.9 kg/m² (±5.2) were continuously monitored for 6-7 days to track free-living PA (light 1.5-3 metabolic equivalents (METs), moderate 3-6 METs and vigorous >6 METs) and sedentary behaviour (<1.5 METs) with the SenseWear Armband. Additional measures included body composition, waist circumference, cardiovascular fitness, total and resting energy expenditure, and various health markers. Appetite control was assessed by validated eating behaviour questionnaires.

RESULTS

Sedentary behaviour (11.06±1.72 h/day) was positively correlated with fat mass (r=0.50, p<0.001) and waist circumference (r=-0.65, p<0.001). Moderate-to-vigorous PA was negatively associated with fat mass (r=-0.72, p<0.001) and remained significantly correlated with adiposity after controlling for sedentary behaviour. Activity energy expenditure was positively associated with the level of PA and negatively associated with fat mass. Disinhibition and binge eating behaviours were positively associated with fat mass (r=0.58 and 0.47, respectively, p<0.001).

CONCLUSIONS

This study demonstrated clear associations among objective measures of PA (and sedentary behaviour), energy expenditure, adiposity and appetite control. The data indicate strong links between physical inactivity and obesity. This relationship is likely to be bidirectional.

Weak Satiety Responsiveness Is a Reliable Trait Associated with Hedonic Risk Factors for Overeating among Women

Some individuals exhibit a weak satiety response to food and may be susceptible to overconsumption. The current study identified women showing consistently low or high satiety responses to standardised servings of food across four separate days and compared them on behavioural, psychological and physiological risk factors for overeating and future weight gain. In a crossover design, 30 female participants (age: 28.0 ± 10.6; body mass index (BMI): 23.1 ± 3.0) recorded sensations of hunger in the post-prandial period following four graded energy level breakfasts. Satiety quotients were calculated to compare individuals on satiety responsiveness across conditions. Body composition, resting metabolic rate (RMR), energy intake, food reward and craving, and eating behaviour traits were assessed under controlled laboratory conditions. A distinct low satiety phenotype (LSP) was identified with good consistency across separate study days. These individuals had a higher RMR, greater levels of disinhibition and reported feeling lower control over food cravings. Further, they consumed more energy and exhibited greater wanting for high-fat food. The inverse pattern of characteristics was observed in those exhibiting a consistently high satiety phenotype (HSP). Weak satiety responsiveness is a reliable trait identifiable using the satiety quotient. The LSP was characterised by distinct behavioural and psychological characteristics indicating a risk for overeating, compared to HSP.

Examination of food reward and energy intake under laboratory and free-living conditions in a trait binge eating subtype of obesity

Background/Aims: Trait binge eating has been proposed as a “hedonic subtype” of obesity characterized by enhanced food liking and wanting, and a preference for high-fat sweet foods in the laboratory. The current study examined the influence of trait binge eating in overweight or obese women on eating behavior under laboratory and free-living conditions over a 48-h period.

Methods: In a matched pairs design, 24 overweight or obese females (BMI: 30.30 ± 2.60 kg/m²; Age: 25.42 ± 3.65 years) with high or low scores on the Binge Eating Scale (BSE) were divided into one of two groups; Obese Binge (O-B) and Obese Non-binge (O-NB). Energy intake was assessed using combined laboratory energy intake measures and 24-h dietary recall procedures. Liking and wanting were assessed using the Leeds Food Preference Questionnaire (LFPQ).

Results: There was a significant association between overall energy consumed, and energy consumed from snack foods under laboratory and free-living conditions. O-B exhibited a greater preference for sweet snack foods in their laboratory and free-living eating behavior. These findings were supported by greater laboratory-based measures of wanting and craving for this food type in O-B. In addition, O-B consumed significantly more energy than their estimated daily energy requirements in the laboratory suggesting that they over-consumed compared to O-NB.

Conclusions: The measurement concordance between laboratory and free-living based energy intake supports the validity of laboratory-based test meal methodologies Variation in trait binge eating was associated with increased craving and wanting for high-fat sweet foods and overconsumption in the laboratory. These findings support the use of trait binge eating as a common hedonic subtype of obesity and extend the relevance of this subtype to habitual patterns of energy intake.

ECO 2013 Report

20th European Congress on Obesity 12-15 May 2013, Liverpool, UK.