Increased energy intake following sleep restriction in men and women: A one-size-fits-all conclusion?

Biomarkers linking habitual short sleep duration with risk of cardiometabolic disease: current progress and future directions

Approximately one in three adults in the United States sleeps less than the recommended 7 h per night. Decades of epidemiological data and data from experimental sleep restriction studies demonstrate short sleep duration is associated with adverse cardiometabolic risk, including risk of type 2 diabetes and cardiovascular disease. However, the precise mechanisms underlying this risk are not fully elucidated and there is a lack of sleep-based interventions designed to mitigate such risk. One strategy to overcome these limitations is to develop biomarkers that link habitual short sleep duration with adverse cardiometabolic risk. Such biomarkers could inform biochemical mechanisms, identify new targets for interventions, support precision medicine by identifying individuals most likely to benefit from sleep-based interventions, and ultimately lead to improved cardiometabolic health in people with habitual short sleep durations. Early progress demonstrates proof-of-principle that omics-based technologies are a viable approach to create biochemical signatures (biomarkers) of short sleep duration, primarily derived from acute studies of experimental sleep restriction. Yet, much work remains. Notably, studies that translate early findings from experimental sleep restriction to free-living adults with habitual short sleep duration have high potential to advance the field. Such studies also create an exciting opportunity for larger randomized controlled trials that simultaneously identify biomarkers of habitual short sleep duration and evaluate the efficacy of sleep-based interventions. Ultimately, early progress in developing molecular biomarkers of short sleep duration combined with the prior decades of progress in the sleep and metabolism fields provide the foundation for exciting progress in the biomarker development space.

Short sleep duration is a novel independent risk factor for overweight and obesity

OBJECTIVES

To investigate the association between sleep duration (SD) and body mass index (BMI) in young adults.

METHODS

This cross-sectional study was carried out between January and September 2022, and the participants were 1724 health sciences students aged 16-22 years, from Imam Abdulrahman Bin Faisal University, Dammam, Saudi Arabia. Measurement of height and weight was carried out and BMI was calculated by the formula=weight in kg/height in m2. Based on SD, subjects were divided into 3 groups: short SD: <7 hours/24 hours; normal SD: 7-9 hours/24 hours; and increased SD: >9 hours/24 hours.

RESULTS

The participants' mean age was 19±3.2 years. Short sleepers had significantly higher BMI (24.2 kg/m2, p<0.001) relative to normal (23.03 kg/m2) and long sleepers (23.2 kg/m2, p=0.041). In addition, short sleep duration (SSD) was associated with overweight (OW) and obesity (OB) (p=0.01). Moreover, multivariate logistic regression analysis found SSD to be an independent risk factor for OW and OB, as it retained its significance (p=0.049) even after adjusting for the major confounding factors of BMI (namely, decreased physical activity and increased food intake). Moreover, it emerged that SSD could lead to 1.47 times higher odds ratio of OW and OB.

CONCLUSION

Participants with a SSD had significantly higher BMI than normal and long sleepers. Short sleep duration is an independent risk factor for increased BMI, which potentially leads to 1.47 times increased odds ratio of having OW and OB.

Sleep Deficiency and Cardiometabolic Disease

Epidemiologic studies have demonstrated that short sleep duration is associated with an increased risk of cardio-metabolic health outcomes including cardiovascular disease mortality, coronary heart disease, type 2 diabetes mellitus, hypertension, and metabolic syndrome. Experimental sleep restriction studies have sought to explain these findings. This review describes the main evidence of these associations and possible mechanisms explaining them. Whether sleep extension reverses these now widely acknowledged adverse health effects and the feasibility of implementing such strategies on a public health level is discussed.

Effects of acute sleep loss on leptin, ghrelin, and adiponectin in adults with healthy weight and obesity: A laboratory study

OBJECTIVE

This study investigated whether blood concentrations of leptin, ghrelin, and adiponectin are affected by acute total sleep deprivation in a sex- and weight-specific manner.

METHODS

A total of 44 participants (mean age 24.9 years; 20 women; 19 with obesity) participated in a crossover design, including one night of sleep deprivation and one night of sleep in the laboratory. After each night, fasting blood was collected.

RESULTS

After sleep deprivation, fasting levels of leptin were lower (mean [SE], vs. sleep: 17.3 [2.6] vs. 18.6 [2.8] ng/mL), whereas those of ghrelin and adiponectin were higher (839.4 [77.5] vs. 741.4 [63.2] pg/mL and 7.5 [0.6] vs. 6.8 [0.6] μg/mL, respectively; all p < 0.05). The changes in leptin and adiponectin following sleep loss were more pronounced among women. Furthermore, the ghrelin increase was stronger among those with obesity after sleep loss. Finally, the sleep loss-induced increase in adiponectin was more marked among normal-weight participants.

CONCLUSIONS

Acute sleep deprivation reduces blood concentrations of the satiety hormone leptin. With increased blood concentrations of ghrelin and adiponectin, such endocrine changes may facilitate weight gain if persisting over extended periods of sleep loss. The observed sex- and weight-specific differences in leptin, ghrelin, and adiponectin call for further investigation.

The role of insufficient sleep and circadian misalignment in obesity

Traditional risk factors for obesity and the metabolic syndrome, such as excess energy intake and lack of physical activity, cannot fully explain the high prevalence of these conditions. Insufficient sleep and circadian misalignment predispose individuals to poor metabolic health and promote weight gain and have received increased research attention in the past 10 years. Insufficient sleep is defined as sleeping less than recommended for health benefits, whereas circadian misalignment is defined as wakefulness and food intake occurring when the internal circadian system is promoting sleep. This Review discusses the impact of insufficient sleep and circadian misalignment in humans on appetite hormones (focusing on ghrelin, leptin and peptide-YY), energy expenditure, food intake and choice, and risk of obesity. Some potential strategies to reduce the adverse effects of sleep disruption on metabolic health are provided and future research priorities are highlighted. Millions of individuals worldwide do not obtain sufficient sleep for healthy metabolic functions. Furthermore, modern working patterns, lifestyles and technologies are often not conducive to adequate sleep at times when the internal physiological clock is promoting it (for example, late-night screen time, shift work and nocturnal social activities). Efforts are needed to highlight the importance of optimal sleep and circadian health in the maintenance of metabolic health and body weight regulation.

Sleep Deficiency and Cardiometabolic Disease

Epidemiologic studies have demonstrated that short sleep duration is associated with an increased risk of cardio-metabolic health outcomes including cardiovascular disease mortality, coronary heart disease, type 2 diabetes mellitus, hypertension, and metabolic syndrome. Experimental sleep restriction studies have sought to explain these findings. This review describes the main evidence of these associations and possible mechanisms explaining them. Whether sleep extension reverses these now widely acknowledged adverse health effects and the feasibility of implementing such strategies on a public health level is discussed.

Sleep Deprivation: Effects on Weight Loss and Weight Loss Maintenance

This narrative review presents the findings from intervention studies on the effects of sleep deprivation on eating habits, metabolic rate, and the hormones regulating metabolism, and discusses their relevance to weight loss efforts. Disturbed sleeping patterns lead to increased energy intake, partly from excessive snacking, mainly on foods high in fat and carbohydrates. The studies focused mainly on the effects of sleep duration, but also of sleep quality, on dietary intake during weight loss trials, and on weight loss maintenance. It is important to explore sleep routines that could enhance the efforts of obese and overweight people to lose weight, maintain their weight loss, and improve their overall health.

Effects of Experimental Sleep Restriction on Energy Intake, Energy Expenditure, and Visceral Obesity

BACKGROUND

Although the consequences of sleep deficiency for obesity risk are increasingly apparent, experimental evidence is limited and there are no studies on body fat distribution.

OBJECTIVES

The purpose of this study was to investigate the effects of experimentally-induced sleep curtailment in the setting of free access to food on energy intake, energy expenditure, and regional body composition.

METHODS

Twelve healthy, nonobese individuals (9 males, age range 19 to 39 years) completed a randomized, controlled, crossover, 21-day inpatient study comprising 4 days of acclimation, 14 days of experimental sleep restriction (4 hour sleep opportunity) or control sleep (9 hour sleep opportunity), and a 3-day recovery segment. Repeated measures of energy intake, energy expenditure, body weight, body composition, fat distribution and circulating biomarkers were acquired.

RESULTS

With sleep restriction vs control, participants consumed more calories (P = 0.015), increasing protein (P = 0.050) and fat intake (P = 0.046). Energy expenditure was unchanged (all P > 0.16). Participants gained significantly more weight when exposed to experimental sleep restriction than during control sleep (P = 0.008). While changes in total body fat did not differ between conditions (P = 0.710), total abdominal fat increased only during sleep restriction (P = 0.011), with significant increases evident in both subcutaneous and visceral abdominal fat depots (P = 0.047 and P = 0.042, respectively).

CONCLUSIONS

Sleep restriction combined with ad libitum food promotes excess energy intake without varying energy expenditure. Weight gain and particularly central accumulation of fat indicate that sleep loss predisposes to abdominal visceral obesity. (Sleep Restriction and Obesity; NCT01580761).

Interindividual differences in energy intake after sleep restriction: The role of personality and implicit attitudes toward food

Sleep restriction (SR) often leads to an increase in energy intake (EI). However, large variability in EI after SR is often observed, which suggests that individual characteristics may affect food intake. The objective of this study was to explore the influence of characteristics generally associated with risk-taking (sensitivity to reward and personality traits: impulsiveness, sensation seeking) and implicit attitudes toward food on EI after sleep loss. 17 subjects completed the NEO-PI-3, an Implicit Association Test measuring implicit attitudes towards healthy and unhealthy foods, and the Sensitivity to Punishment and Sensitivity to Reward Questionnaire. 24h Ad libitum EI was assessed following a habitual sleep night, a 50% SR with an advanced wake time, and a 50% SR with a delayed bedtime. Changes in EI between each SR condition and the control condition (ΔEI) were calculated for each subject. Despite no changes in overall EI between sleep conditions, results showed large interindividual variations (-669 to +899 kcal) across SR conditions. Regression modeling showed that a lower sensation seeking and higher favorable implicit attitudes towards unhealthy food were significantly associated with increased ΔEI in the advanced wake time condition. For the delayed bedtime, lower sensation seeking was associated with increased ΔEI while controlling for age, sex, REM sleep, and implicit attitudes. These results suggest that certain personality traits and implicit attitudes toward food are associated with changes in EI after sleep loss.

Effect of sleep duration on dietary intake, desire to eat, measures of food intake and metabolic hormones: A systematic review of clinical trials

BACKGROUND AND AIMS

Sleep, as well as diet and physical activity, plays a significant role in growth, maturation, health, and regulation of energy homeostasis. Recently, there is increasing evidence indicating a possible causal association between sleep duration and energy balance. We aimed to examine the relationship between sleep duration and food consumption, energy intake, anthropometric characteristics, and appetite-regulating hormones by randomized controlled trials (RCTs).

METHODS

Electronic literature searches were conducted on Medline, Web of Science, and Google Scholar until July 2020. The search was conducted with the following words: "Sleep Duration", "Circadian Rhythm", "Sleep Disorders" in combination with "Obesity", "Overweight", "Abdominal Obesity", "Physical Activity", "Energy Intake", "Body Mass Index", "Lipid Metabolism", "Caloric Restriction", Leptin, "Weight Gain", and "Appetite Regulation" using human studies.methods RESULTS: After screening 708 abstracts, 50 RCTs (7 on children or adolescents and 43 on adults) were identified and met the inclusion criteria. In general, the findings suggested that sleep restriction may leads to a significant increment in energy intake, fat intake, body weight, appetite, hunger, eating occasions, and portion size, while protein and carbohydrate consumption, total energy expenditure, and respiratory quotient remained unaffected as a result of sleep restriction. Serum leptin, ghrelin, and cortisol concentrations were not influenced by sleep duration as well.

CONCLUSION

Insufficient sleep can be considered as a contributing factor for energy imbalance, weight gain, and metabolic disorders and it is suggested that to tackle disordered eating it may be necessary to pay more attention to sleep duration.

Effects of ad libitum food intake, insufficient sleep and weekend recovery sleep on energy balance

STUDY OBJECTIVES

Insufficient sleep is believed to promote positive energy balance (EB) and weight-gain. Increasing weekend sleep duration to "recover" from weekday sleep loss is common, yet little is known regarding how weekend recovery sleep influences EB. We conducted a randomized controlled trial to assess how: 1) 2 days and 8 days of insufficient sleep and 2) ad libitum weekend recovery sleep impact EB (energy intake [EI] - energy expenditure [EE]).

METHODS

Following ten baseline days with 9h per night sleep opportunities, participants completed one of three 10-day experimental protocols with ad libitum EI: control (9h sleep opportunities; n=8; 23±5y [mean±SD]); sleep restriction (SR; 5h sleep opportunities; n=14; 25±5y); sleep restriction with weekend recovery sleep (SR+WR; 5 days insufficient sleep, 2 days ad libitum weekend recovery sleep, 3 days recurrent insufficient sleep; n=14; 27±4y).

RESULTS

24h EB increased (P < 0.001; main effect) by an average of 797.7±96.7 (±SEM) kcal during the 10-day experimental protocol versus baseline with no significant differences between groups. Percent change from baseline in 24h-EE was higher (P < 0.05) on day 2 of insufficient sleep (SR and SR+WR groups; 10±1%) versus adequate sleep (control group; 4±3%).

CONCLUSIONS

In this between-group study, the effects of adequate sleep and insufficient sleep, with or without or weekend recovery sleep, on 24h-EB were similar. Examining EB and body weight changes using within-subject cross-over designs and "free-living" conditions outside the laboratory (e.g., sleep extension) are needed to advance our understanding of the links between insufficient sleep, weekend recovery sleep and weight-gain.

Actigraphy-Derived Sleep Is Associated with Eating Behavior Characteristics

Poor sleep is a determinant of obesity, with overconsumption of energy contributing to this relationship. Eating behavior characteristics are predictive of energy intake and weight change and may underlie observed associations of sleep with weight status and obesity risk factors. However, relationships between sleep and dimensions of eating behavior, as well as possible individual differences in these relations, are not well characterized. Therefore, the aim of this study was to evaluate whether sleep behaviors, including duration, timing, quality, and regularity relate to dietary restraint, disinhibition, and tendency towards hunger and to explore whether these associations differ by sex. This cross-sectional study included 179 adults aged 20–73 years (68.7% women, 64.8% with BMI ≥ 25 kg/m²). Sleep was evaluated by accelerometry over 2 weeks. Eating behavior dimensions were measured with the Three-Factor Eating Questionnaire. Prolonged wake after sleep onset (WASO) (0.029 ± 0.011, p = 0.007), greater sleep fragmentation index (0.074 ± 0.036, p = 0.041), and lower sleep efficiency (−0.133 ± 0.051, p = 0.010) were associated with higher dietary restraint. However, higher restraint attenuated associations of higher WASO and sleep fragmentation with higher BMI (p-interactions < 0.10). In terms of individual differences, sex influenced associations of sleep quality measures with tendency towards hunger (p-interactions < 0.10). Stratified analyses showed that, in men only, higher sleep fragmentation index, longer sleep onset latency, and lower sleep efficiency were associated with greater tendency towards hunger (β = 0.115 ± 0.037, p = 0.003, β = 0.169 ± 0.072, p = 0.023, β = −0.150 ± 0.055, p = 0.009, respectively). Results of this analysis suggest that the association of poor sleep on food intake could be exacerbated in those with eating behavior traits that predispose to overeating, and this sleep-eating behavior relation may be sex-dependent. Strategies to counter overconsumption in the context of poor quality sleep should be evaluated in light of eating behavior traits.

The influence of sleep health on dietary intake: a systematic review and meta-analysis of intervention studies

BACKGROUND

Poor dietary intake increases disease risk, and poor sleep influences diet. This systematic review and meta-analysis of intervention studies aimed to evaluate the effect of sleep health on dietary intake in adults.

METHODS

Five online databases were used to identify studies published between 1970 and 2019. Included studies were interventions that modified sleep and reported dietary outcomes.

RESULTS

Fifty four full texts were assessed and 24 publications were included. Following risk of bias appraisal, data were narratively summarised and a sub-group of studies (n = 15) was meta-analysed to determine the effect of sleep on dietary intake. One intervention modified sleep timing and 23 modified duration. Sleep duration was partially restricted (≤5.5 h night^-1 ) (n = 16), totally restricted (n = 4), partially and totally restricted (n = 1), and extended (n = 2). Dietary outcomes were energy intake (n = 24), carbohydrate, fat, protein intake (n = 20), single nutrient intake (n = 5), diet quality (n = 1) and food types (n = 1). Meta-analysis indicated partial sleep restriction results in higher energy intake in intervention compared with control [standardised mean difference (SMD) = 0.37; 95% confidence interval (CI) = 0.21-0.52; P < 0.001], with a mean difference of 204 kcal (95% CI = 112-295; P < 0.001) in daily energy intake, and a higher percentage of energy from fat, protein, carbohydrate (fat: SMD = 0.33; 95% CI = 0.16-0.51; P < 0.001; protein: SMD = 0.30, 95% CI = 0.12-0.47, P = 0.001; carbohydrate: SMD = 0.22, 95% CI = 0.04-0.39, P = 0.014).

CONCLUSIONS

Partial sleep restriction with duration of ≤5.5 h day^-1 increases daily energy intake, as well as fat, protein and carbohydrate intake. Further research is needed to determine the relationship between other dimensions of sleep health and dietary intake.

Acute Sleep Curtailment Increases Sweet Taste Preference, Appetite and Food Intake in Healthy Young Adults: A Randomized Crossover Trial

This study aimed to examine the effect of acute sleep curtailment on sweet taste preference, appetite and food intake, and the correlation between food intake and sweet taste preference or active ghrelin using a randomized crossover design (5 h sleep curtailment vs. 8 h control). Twenty-four participants (11 men) aged 21.4 ± 1.0 years, with BMI 19.8 ± 1.7 kg/m², who habitually slept 5 h/night or more experienced interventions lasting three consecutive nights. Participants came into the laboratory for testing on day 4. Fasting blood tests were conducted at 8:00 a.m. to measure active ghrelin and leptin levels. Sweet taste preference was assessed by presenting five different concentration sucrose solutions at 9:00 a.m. Ad libitum intake at breakfast was assessed for 30 min from 9:30 a.m. Sweet taste preference was higher following sleep curtailment than control. Active ghrelin was likewise higher following sleep curtailment than control. Leptin did not differ between conditions. Energy intake was higher following sleep curtailment than control, being derived primarily from carbohydrates. However, sweet taste preference and active ghrelin did not correlate with energy intake. These results suggest that acute consecutive sleep curtailment increases sweet taste preference, active ghrelin, and energy intake in healthy young adults.

Nutritional Recommendations for Physique Athletes

The popularity of physique sports is increasing, yet there are currently few comprehensive nutritional guidelines for these athletes. Physique sport now encompasses more than just a short phase before competition and offseason guidelines have recently been published. Therefore, the goal of this review is to provide an extensive guide for male and female physique athletes in the contest preparation and recovery period. As optimal protein intake is largely related to one’s skeletal muscle mass, current evidence supports a range of 1.8-2.7 g/kg. Furthermore, as a benefit from having adequate carbohydrate to fuel performance and activity, low-end fat intake during contest preparation of 10-25% of calories allows for what calories remain in the “energy budget” to come from carbohydrate to mitigate the negative impact of energy restriction and weight loss on training performance. For nutrient timing, we recommend consuming four or five protein boluses per day with one consumed near training and one prior to sleep. During competition periods, slower rates of weight loss (≤0.5% of body mass per week) are preferable for attenuating the loss of fat-free mass with the use of intermittent energy restriction strategies, such as diet breaks and refeeds, being possibly beneficial. Additionally, physiological and psychological factors are covered, and potential best-practice guidelines are provided for disordered eating and body image concerns since physique athletes present with higher incidences of these issues, which may be potentially exacerbated by certain traditional physique practices. We also review common peaking practices, and the critical transition to the post-competition period.

Sleep and obesity: the mediating role of health behaviors among African Americans

OBJECTIVES

To examine the role of health behaviors (eg, physical activity, sedentary behaviors, and diet) in the relationship between sleep (ie, duration and quality) and BMI among African American adults.

DESIGN

A cross-sectional self-report questionnaire included questions related to health and health-related behaviors.

SETTING

This study was based on data from the CHURCH study, which aimed to address cancer health disparities among church-going African Americans in Houston, TX.

PARTICIPANTS

African American adults were recruited from three large community churches. The sample included a total of 1837 participants (75.2% female; mean age 48.2 ± 13.7y; mean BMI 32.0 ± 7.5 kg/m²).

MEASUREMENTS

Linear regression models and path analyses controlling for demographic characteristics and depression estimated the associations between sleep and BMI as well as the mediating roles of health behaviors.

RESULTS

The average self-reported sleep duration was 6.2 ± 1.5 h/night with 61%, 35.8%, and 1.6% reporting short (≤6 h/night), normal (7-9 h/night), and long sleep (≥10 h/night), respectively. Short sleep was related to greater BMI (b = 1.37, SE = 0.38, P = .01), and the relationship was mediated by sedentary behaviors (est. = 0.08, SE = 0.04, 95% CI: 0.02, 0.17).

CONCLUSIONS

Short sleep and poor quality sleep was related to poor diet and physical activity-related health behaviors, and BMI. The link between sleep and obesity is, in part, due to energy imbalance from increased sedentary behavior.

Sleep influences on obesity, insulin resistance, and risk of type 2 diabetes

A large body of epidemiologic evidence has linked insufficient sleep duration and quality to the risk of obesity, insulin resistance and type 2 diabetes. To address putative causal mechanisms, this review focuses on laboratory interventions involving several nights of experimental sleep restriction, fragmentation or extension and examining metabolically relevant outcomes. Sleep restriction has been consistently shown to increase hunger, appetite and food intake, with the increase in caloric intake in excess of the energy requirements of extended wakefulness. Findings regarding decreases in hormones promoting satiety or increases in hormones promoting hunger have been less consistent, possibly because of confounding effects of changes in adiposity when energy intake was not controlled and sampling protocols that did not cover the entire 24-h cycle. Imaging studies revealed alterations in neuronal activity of brain regions involved in food reward. An adverse impact of experimental sleep restriction on insulin resistance, leading to reduced glucose tolerance and increased diabetes risk, has been well-documented. There is limited evidence indicating that sleep fragmentation without reduction in sleep duration also results in a reduction in insulin sensitivity. The adverse metabolic outcomes of sleep disturbances appear to involve multiple mechanistic pathways acting in concert. Emerging evidence supports the benefits of behavioral, but not pharmacological, sleep extension on appetite and glucose metabolism. Further research should focus on the feasibility and efficacy of strategies to optimize sleep duration and quality on obesity and diabetes risk in at-risk populations as well as those with established diseases. Further work is needed to identify mechanistic pathways.