Adaptations to a diet-based weight-reducing programme in obese women resistant to weight loss

The relationship between sleep quantity, sleep quality and weight loss in adults: A scoping review

Sleep is hypothesized to interact with weight gain and loss; however, modelling this relationship remains elusive. Poor sleep perpetuates a cascade of cardiovascular and metabolic consequences that may not only increase risk of adiposity, but also confound weight loss efforts. We conducted a scoping review to assess the research on sleep and weight loss interventions. We searched six databases for studies of behavioural weight loss interventions that included assessments of sleep in the general, non-clinical adult human population. Our synthesis focused on dimensions of Population, Intervention, Control, and Outcomes (PICO) to identify research and knowledge gaps. We identified 35 studies that fell into one of four categories: (a) sleep at baseline as a predictor of subsequent weight loss during an intervention, (b) sleep assessments after a history of successful weight loss, (c) concomitant changes in sleep associated with weight loss and (d) experimental manipulation of sleep and resulting weight loss. There was some evidence of improvements in sleep in response to weight-loss interventions; however, randomized controlled trials of weight loss interventions tended not to report improvements in sleep when compared to controls. We conclude that baseline sleep characteristics may predict weight loss in studies of dietary interventions and that sleep does not improve because of weight loss alone. Future studies should enrol large and diverse, normal, overweight and obese short sleepers in trials to assess the efficacy of sleep as a behavioural weight loss treatment.

Associations of timing of food intake with energy intake, eating behaviour traits and psychosocial factors in adults with overweight and obesity

Introduction

Whether a late distribution of food intake impacts obesity through increased energy intake remains uncertain and the behavioural characterization of late eating needs to be further investigated. The first objective of this study was to assess the associations between late eating and body mass index (BMI) and total energy intake (TEI), and whether TEI mediates the association between late eating and BMI. The second objective was to assess the associations between late eating and eating behaviour traits or psychosocial factors and whether eating behaviour traits mediate the association between late eating and TEI.

Methods

Baseline data from 301 individuals (56% women, age = 38.7 ± 8.5 years; BMI = 33.2 ± 3.4 kg/m²), who participated in four weight loss studies were used in this cross-sectional study. Total energy intake was assessed using a three-day food record from which the percentage of TEI after 17:00 and after 20:00 was calculated. Eating behaviour traits and psychosocial factors were assessed with questionnaires. Pearson correlations and mediation analyses adjusted for age, sex, underreporting of energy intake, sleep duration and bedtime were performed.

Results

Percent TEI after 17:00 and after 20:00 were associated with TEI (r = 0.13, p = 0.03 for both), and TEI mediated the association between percent TEI after 17:00 and BMI (β = 0.01 ± 0.01, 95% CI: 0.001, 0.02). Percent TEI after 17:00 was associated with disinhibition (r = 0.13, p = 0.03) and percent TEI after 20:00 was associated with susceptibility to hunger (r = 0.13, p = 0.03), stress (r = 0.24, p = 0.002) and anxiety (r = 0.28, p = 0.0004). In women, disinhibition mediated the association between percent TEI after 17:00 and TEI (β = 3.41 ± 1.43, 95% CI: 0.92, 6.47). Susceptibility to hunger mediated the association between percent TEI after 20:00 and TEI (β = 0.96 ± 0.59, 95% CI: 0.02, 2.34) in men and women.

Conclusion

Late eating is associated with TEI and suboptimal eating behaviours which could contribute to explaining the association between timing of food intake and obesity.

Eating behaviour traits mediate the association between satiety responsiveness and energy intake among individuals with overweight and obesity

Whether eating behaviour traits represent factors that could explain the susceptibility to overeating in individuals with low satiety responsiveness remain to be extensively examined. This study aimed to assess if eating behaviours mediate the association between satiety responsiveness and energy intake. Baseline data from individuals with overweight or obesity (n = 303; age = 38.7 ± 8.4 years; BMI = 33.2 ± 3.4 kg/m², 56% women) who participated in four weight-loss studies were included in this cross-sectional study. Satiety responsiveness was determined by the satiety quotient (SQ) based on fullness sensations in response to a standardized breakfast. Energy intake was self-reported in a three-day food record and measured by an ad libitum buffet meal. Eating behaviours were assessed with questionnaires. Mediation analyses adjusted for age and sex, and for underreporting for the food record, were performed using a regression-based and bootstrapping approach. The association between SQ and self-reported total energy intake was mediated by susceptibility to hunger (β = -2.51 ± 1.26, 95% CI, -5.38 to -0.52) and its subscales, internal and external locus of hunger (β = -2.00 ± 1.10, 95% CI, -4.50 to -0.28 and β = -2.42 ± 1.29, 95% CI, -5.30 to -0.30, respectively). Susceptibility to hunger (β = -2.71 ± 1.13, 95% CI, -5.29 to -0.84), internal and external locus of hunger (β = -1.84 ± 0.95, 95% CI -4.00 to -0.30 and β = -3.42 ± 1.31, 95% CI, -6.39 to -1.24, respectively), cues that may trigger food cravings (β = -5.43 ± 2.91, 95% CI, -11.83 to -0.44) and state-craving as a physiological state (β = -4.31 ± 2.51, 95%CI, -10.14 to -0.44) also mediated the association between SQ and measured energy intake. These results suggest that susceptibility to hunger and food cravings partly explained the susceptibility to overeating among individuals with low satiety responsiveness. Interventions targeting susceptibility to hunger and food cravings may thus be helpful to prevent overeating among these individuals.

The consequences of a weight-centric approach to healthcare: A case for a paradigm shift in how clinicians address body weight

Current healthcare is weight-centric, equating weight and health. This approach to healthcare has negative consequences on patient well-being. The aim of this article is to make a case for a paradigm shift in how clinicians view and address body weight. In this review, we (1) address common flawed assumptions in the weight-centric approach to healthcare, (2) review the weight science literature and provide evidence for the negative consequences of promoting dieting and weight loss, and (3) provide practice recommendations for weight-inclusive care.

What Is the Profile of Overweight Individuals Who Are Unsuccessful Responders to a Low-Energy Diet? A PREVIEW Sub-study

This study was performed to evaluate the profile of overweight individuals with pre-diabetes enrolled in PREVIEW who were unable to achieve a body weight loss of ≥8% of the baseline value in response to a 2-month low-energy diet (LED). Their baseline profile reflected potential stress-related vulnerability that predicted a reduced response of body weight to a LED programme. The mean daily energy deficit maintained by unsuccessful weight responders of both sexes was less than the estimated level in successful female (656 vs. 1,299 kcal, p < 0.01) and male (815 vs. 1,659 kcal, p < 0.01) responders. Despite this smaller energy deficit, unsuccessful responders displayed less favorable changes in susceptibility to hunger and appetite sensations. They also did not benefit from the intervention regarding the ability to improve sleep quality. In summary, these results show that some individuals display a behavioral vulnerability which may reduce the ability to lose weight in response to a diet-based weight loss program. They also suggest that this vulnerability may be accentuated by a prolonged diet restriction.

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.

Weight change adjusted equations for assessing resting metabolic rate in overweight and obese adults

BACKGROUND

Although over one hundred equations have been developed to predict the energy expenditure of individuals, none are sensitive to weight change in assessment of resting metabolic rate (RMR) before and after weight loss.

OBJECTIVE

To formulate adjusted equations for overweight and obese individuals and to compare their accuracy with existing prediction RMR equations before and after weight loss.

SUBJECTS/MATERIALS

This is historical prospective study. Participants included 39 overweight and obese men and women before and after losing 10-20% from baseline weight on a diet and physical activity regimen for at least three months. Pre and post weight loss measured RMR results were compared to estimated RMR using several existing prediction equations: Harris and Benedict, Ravussin and Bogardus, and Mifflin et al. To improve the accuracy of these prediction equations, we suggest new equations adjusted for weight loss, based on measured RMR and evaluated their accuracy.

RESULTS

Pre and post weight loss data indicated: significant fat reduction in both genders; reduction in free-fat mass only in men, and a significant decrease in measured RMR only in women. Our suggested equations were the most accurate and closest to measured RMR in both genders, in comparison to the Harris and Benedict, Ravussin and Bogardus, and Mifflin et al equation results. Estimated RMR using the latter equations was significantly lower than measured RMR in both genders at pre and post weight loss (P < 0.01).

CONCLUSIONS

This study highlights the need for adjusting RMR equations before and after weight loss in overweight and obese individuals. Further research is needed to validate our suggested equations.

Early changes in appetite and energy expenditure are not associated to body weight and fat losses in pre-menopausal women living with overweight/obesity

BACKGROUND

The aim of the study was to investigate whether early changes (1-week) in energy balance-related measures would predict changes in body weight (BW) and fat losses in women living with overweight/obesity.

METHODS

BW, body composition (DXA), resting energy expenditure (REE)(indirect calorimetry), olfactory performance (Sniffin' Sticks), appetite and palatability (visual analogue scale) were measured at baseline, after a 1-week of caloric restriction as well as post-intervention (at 10 and 20 weeks) in a group of 30 women living with overweight/obesity.

RESULTS

A significant decrease in REE (p = 0.033) was noted after 1 week. Fasting desire to eat (p = 0.004), hunger (p = 0.001) and prospective food consumption (p = 0.001) all increased after 1 week. Similarly, significant increases in AUC SQ for desire to eat (p = 0.01), hunger (p = 0.005) and prospective food consumption (p = 0.001) were noted after 1 week. However, these early changes were not associated to final BW or FM losses at the end of the weight loss intervention.

CONCLUSION

Despite significant changes in REE and appetite soon after the onset of a BW loss intervention, these early changes do not seem to predict final BW or FM losses at the end of the program in women living with overweight/obesity.

Is the timing of food intake a potential indicator of low weight loss responders? A secondary analysis of three weight loss studies

Individual variability in weight loss in response to a weight loss intervention is commonly observed. Recently, the timing of food intake has been identified as one possible factor implicated in obesity and weight loss. The objective of this study was to further characterize low weight loss responders by assessing the pre-diet distribution of daily energy and macronutrient intakes. A pooled cohort of men and women (n = 122; aged 39.1 ± 8.2 years; body mass index [BMI] 33.1 ± 3.8 kg/m² ) who participated in a 12 to 15 week energy-restricted intervention (-500 to -700 kcal/d) were included in this study. Participants were categorized into two weight loss groups (ie, low [-1.3 ± 2.3 kg] and high [-6.1 ± 2.1 kg] weight loss). Food intake and distribution of energy and macronutrient intakes were assessed using a 3-day food record at baseline. The daily distribution of energy intake (% of total energy intake) was similar in the two weight loss groups with the exception of the low weight loss group who consumed a slightly lower proportion of their total energy intake before 9:00 am compared with the high weight loss group (12.5% ± 5.8% vs 15.0% ± 6.6%, respectively, P = .03). In the low weight loss group, the percentage of energy intake consumed after 8:00 pm was positively associated with total energy intake (r = 0.27, P = .04). The results of this study suggest that the timing of food intake measured prior to a weight loss intervention does not permit the characterization of low weight loss responders.

Issues in Measuring and Interpreting Human Appetite (Satiety/Satiation) and Its Contribution to Obesity

PURPOSE OF REVIEW

The goals of this paper are to report current research practices in investigations of human appetite control and to assess their relationships with emerging theoretical principles. Appetite is often distinguished by the separation of homeostatic and hedonic processes.

RECENT FINDINGS

This report assesses the validity of a homeostatic toolkit to measure subjectively perceived hunger and its relationship to the developing processes of satiation (control of meal size) and satiety (control of the post-eating period). The capacity of a procedure to measure the influence of hedonic processes on food intake is also evaluated. A major issue is the relationship between the pattern of eating behaviour (influenced by the underlying drive to eat and the inhibition induced by the act of eating itself) and the parallel underlying profile of hormonal and other metabolic biomarkers. Increasing recognition is being given to individual variability in the expression of appetite, and the fact that the use of the average (mean) response conceals important information about the nature of appetite control. There is a growing interest in the identification of satiety phenotypes that operate in parallel to metabolic phenotypes. Interestingly, energy expenditure (metabolic and behavioural) contributes to an energy balance framework for understanding energy intake (appetite).

Examining changes in respiratory exchange ratio within an 8-week weight loss intervention

BACKGROUND

Maintaining weight loss is difficult, partly as a result of accompanying reductions in fat oxidation. The present study examined fat oxidation [reflected by respiratory exchange ratio (RER)] within an 8-week, self-led weight loss intervention. Changes in RER, body fat (BF%) and estimated energy expenditure (EE) were examined.

METHODS

Twenty-two adults [13 females, nine males; mean (SD) age 34.6 (16.5) years; body mass index 32.0 (4.3) kg m^-2 ] received a self-directed workbook; twelve were also randomised to receive a self-monitoring wrist-worn device. At weeks 0 and 8, RER (indirect calorimetry), BF% (BodPod) and estimated EE [7-day physical activity recall (PAR-EE) were collected. Participants were pooled and paired t-tests were used to examine changes over time. Correlations explored associations among variables. Participants were then dichotomised into weight loss group (WL) or weight stable/gainers group (WSG) and eating behaviours [Intuitive Eating Scale (IES-2)] were examined by 2 × 2 repeated measures multivariate analysis of covariance.

RESULTS

There were no significant changes in RER, body fat percentage and PAR-EE. A significant negative association was found between week 8 PAR-EE and week 8 RER, as well as between BF% change and RER change. There was a significant time by WL versus WSG group effect of IES-2 scores, with the WL group self-reporting significantly increased scores in Eating for Physical Reasons rather than Emotional Reasons (EPR) subscale.

CONCLUSIONS

Increased physical activity after an 8-week weight loss intervention was associated with a higher fasting fat oxidation. Participants who increased EPR scores were more successful in weight loss than those without a change in this subscale.

Diet-resistant obesity is characterized by a distinct plasma proteomic signature and impaired muscle fiber metabolism

Background/Objectives:

Inter-individual variability in weight loss during obesity treatment is complex and poorly understood. Here we use whole body and tissue approaches to investigate fuel oxidation characteristics in skeletal muscle fibers, cells and distinct circulating protein biomarkers before and after a high fat meal (HFM) challenge in those who lost the most (obese diet-sensitive; ODS) vs the least (obese diet-resistant; ODR) amount of weight in a highly controlled weight management program.

Subjects/Methods:

In 20 weight stable-matched ODS and ODR women who previously completed a standardized clinical weight loss program, we analyzed whole-body energetics and metabolic parameters in vastus lateralis biopsies and plasma samples that were obtained in the fasting state and 6 h after a defined HFM, equivalent to 35% of total daily energy requirements.

Results:

At baseline (fasting) and post-HFM, muscle fatty acid oxidation and maximal oxidative phosphorylation were significantly greater in ODS vs ODR, as was reactive oxygen species emission. Plasma proteomics of 1130 proteins pre and 1, 2, 5 and 6 h after the HFM demonstrated distinct group and interaction differences. Group differences identified S-formyl glutathione hydratase, heat shock 70 kDA protein 1A/B (HSP72), and eukaryotic translation initiation factor 5 (eIF5) to be higher in ODS vs ODR. Group-time differences included aryl hydrocarbon interacting protein (AIP), peptidylpropyl isomerase D (PPID) and tyrosine protein-kinase Fgr, which increased in ODR vs ODS over time. HSP72 levels correlated with muscle oxidation and citrate synthase activity. These proteins circulate in exosomes; exosomes isolated from ODS plasma increased resting, leak and maximal respiration rates in C2C12 myotubes by 58%, 21% and 51%, respectively, vs those isolated from ODR plasma.

Conclusions:

Findings demonstrate distinct muscle metabolism and plasma proteomics in fasting and post-HFM states corresponding in diet-sensitive vs diet-resistant obese women.

Mechanisms responsible for homeostatic appetite control: theoretical advances and practical implications

Homeostatic appetite control is part of a psychobiological system that has evolved to maintain an adequate supply of nutrients for growth and maintenance. The system links the physiological needs for energy with the behaviour that satisfies these needs (feeding), and is shaped by excitatory and inhibitory signals. Owing to rapid shifts in the food environment, homeostatic appetite control is not well adapted for modern-day human functioning. Areas covered: Homeostatic appetite control has two divisions. Tonic processes exert stable and enduring influences, with signals arising from bodily tissues and metabolism. Episodic processes fluctuate rapidly and are related to nutrient ingestion and the composition of foods consumed. Research in these areas incorporates potent endocrine signals that can influence behaviour. Expert commentary: The regulation of adipose tissue, and its impact on appetite (energy) homeostasis, has been heavily researched. More recently however, it has been demonstrated that fat-free mass has the potential to act as a tonic driver of food intake. A challenging issue is to determine how the post-prandial action of episodic satiety hormones and gastrointestinal mechanisms can effectively brake the metabolic drive to eat, in order to keep food intake under control and prevent a positive energy balance and fat accumulation.

Weight Loss and Appetite Control in Women

PURPOSE OF REVIEW

The aim of this review is to describe and discuss weight loss-induced variations in appetite in women and factors responsible for these changes.

RECENT FINDINGS

Studies have shown postweight loss increases in fasting and postprandial appetite in individuals engaged in weight loss trials, especially in women. Similarly, appetite-related peptides associated to the homeostatic control of feeding, such as leptin, ghrelin and peptide YY, were also found to be altered in way that promotes increased appetite after weight loss interventions. Sustained caloric deficits also drive increases in the frequency and strength of food cravings, food reward and seem to enhance oro-sensory sensations in women who lost weight. The menstrual cycle has also been to shown to influence caloric intake in women, more specifically food cravings. On the other hand, caloric restriction seems to increase cognitive restraint, decrease habitual disinhibition and susceptibility to hunger among women engaged in weight loss trials. Neural analysis corroborates these results, showing increased activation in brain areas involved in food reward and self-control processing. In conclusion, evidence supports that weight loss increases appetite sensations, and promotes changes in homeostatic and non-homeostatic control of feeding, which collectively seem to upregulate appetite in women.