Spaeth AM; Dinges DF; Goel N. Effects of experimental sleep restriction on weight gain, caloric intake, and meal timing in healthy adults. 2013;36(7):981-990.

Background: Evidence indicates that men and African Americans may be more susceptible to weight gain resulting from sleep loss than women and whites, respectively. Increased daily caloric intake is a major behavioral mechanism that underlies the relation between sleep loss and weight gain. Objective: We sought to assess sex and race differences in caloric intake, macronutrient intake, and meal timing during sleep restriction. Design: Forty-four healthy adults aged 21-50 y (mean 6 SD: 32.7 6 8.7 y; n = 21 women, n = 16 whites) completed an in-laboratory protocol that included 2 consecutive baseline nights [10 or 12 h time in bed (TIB)/night; 2200-0800 or 2200-1000] followed by 5 consecutive sleep-restriction nights (4 h TIB/night; 0400-0800). Caloric intake and meal-timing data were collected during the 2 d after baseline sleep and the first 3 d after sleep restriction. Results: During sleep restriction, subjects increased daily caloric intake (P , 0.001) and fat intake (P = 0.024), including obtaining more calories from condiments, desserts, and salty snacks (Ps , 0.05) and consumed 532.6 6 295.6 cal during late-night hours (2200-0359). Relative to women, men consumed more daily calories during baseline and sleep restriction, exhibited a greater increase in caloric intake during sleep restriction (d = 0.62), and consumed a higher percentage of daily calories during late-night hours (d = 0.78, Ps , 0.05). African Americans and whites did not significantly differ in daily caloric intake, increased caloric intake during sleep restriction, or meal timing. However, African Americans consumed more carbohydrates, less protein, and more caffeine-free soda and juice than whites did during the study (Ps , 0.05). Conclusions: Men may be more susceptible to weight gain during sleep loss than women due to a larger increase in daily caloric intake, particularly during late-night hours. These findings are relevant to the promotion of public health awareness by highlighting nutritional risk factors and modifiable behaviors for weight gain related to sleep-wake timing. This trial was registered at clinicaltrials.gov as NCT02128737 and NCT02130791.

U.S. population time use survey findings suggest that interventions to increase sleep time should concentrate on delaying the morning start time of work and educational activities (or making them more flexible), increasing sleep opportunities, and shortening morning and evening commute times. Reducing the need for multiple jobs may increase sleep time, but economic disincentives from working fewer hours will need to be offset. Raising awareness of the importance of sufficient sleep for health and safety may be necessary to positively influence discretionary behaviors that reduce sleep time, including television viewing and morning grooming.

Previous research has suggested that vegetarianism may serve as a mask for restrained eating. The purpose of this study was to compare the dietary habits and lifestyle behaviors of vegetarians (n=55), pesco-vegetarians (n=28), semi-vegetarians (n=29), and flexitarians (n=37), to omnivores (n=91), who do not restrict animal products from their diets. A convenience sample of college-age females completed questionnaires about their eating habits, food choice motivations, and personality characteristics. Results indicated that while vegetarians and pesco-vegetarians were more open to new experiences and less food neophobic, they were not more restrained than omnivores. Rather semi-vegetarians; those who restricted only red meat from their diet, and flexitarians; those who occasionally eat red meat, were significantly more restrained than omnivores. Whereas food choices of semi-vegetarians and flexitarians were motivated by weight control, vegetarians and pesco-vegetarians' food choices were motivated by ethical concerns. By focusing specifically on semi-vegetarian and flexitarian subgroups, more effective approaches can be developed to ensure that their concerns about weight loss do not lead to unhealthful or disordered eating patterns.

No abstract

Although insufficient sleep is a well-recognized risk factor for overeating and weight gain, the neural mechanisms underlying increased caloric (particularly fat) intake after sleep deprivation remain unclear. Here we used resting-state functional magnetic resonance imaging and examined brain connectivity changes associated with macronutrient intake after one night of total sleep deprivation (TSD). Compared to the day following baseline sleep, healthy adults consumed a greater percentage of calories from fat and a lower percentage of calories from carbohydrates during the day following TSD. Subjects also exhibited increased brain connectivity in the salience network from the dorsal anterior cingulate cortex (dACC) to bilateral putamen and bilateral anterior insula (aINS) after TSD. Moreover, dACC-putamen and dACC-aINS connectivity correlated with increased fat and decreased carbohydrate intake during the day following TSD, but not during the day following baseline sleep. These findings provide a potential neural mechanism by which sleep loss leads to increased fat intake.

Objective Short sleep duration is a significant risk factor for weight gain, particularly in African Americans and men. Increased caloric intake underlies this relationship but it remains unclear whether decreased energy expenditure is a contributory factor. The current study assessed the impact of sleep restriction and recovery sleep on energy expenditure in African American and Caucasian men and women. Methods Healthy adults participated in a controlled laboratory study. After two baseline sleep nights, subjects were randomized to an experimental (n=36; 4h sleep/night for 5 nights followed by 1 night 12h recovery sleep) or control condition (n=11; 10h sleep/night). Resting metabolic rate and respiratory quotient were measured using indirect calorimetry in the morning after overnight fasting. Results Resting metabolic rate—the largest component of energy expenditure—decreased after sleep restriction (−2.6%, p=0.032) and returned to baseline levels after recovery sleep. No changes in resting metabolic rate were observed in control subjects. Relative to Caucasians (n=14), African Americans (n=22) exhibited comparable daily caloric intake but a lower resting metabolic rate (p=0.043) and higher respiratory quotient (p=0.013) regardless of sleep duration. Conclusions Sleep restriction decreased morning resting metabolic rate in healthy adults, suggesting that sleep loss leads to metabolic changes aimed at conserving energy.

Insomnia is related to an increased risk of eating disorders, while eating disorders are related to more disrupted sleep. Insomnia is also linked to poorer treatment outcomes for eating disorders. However, over the last decade, studies examining sleep and eating disorders have relied on surveys, with no objective measures of sleep for anorexia nervosa or bulimia nervosa, and only actigraphy data for binge eating disorder. Sleep disturbance is better defined for night eating syndrome, where sleep efficiency is reduced and melatonin release is delayed. Studies that include objectively measured sleep and metabolic parameters combined with psychiatric comorbidity data would help identify under what circumstances eating disorders and sleep disturbance produce an additive effect for symptom severity and for whom poor sleep would increase risk for an eating disorder. Cognitive behavior therapy for insomnia may be a helpful addition to treatment of those with both eating disorder and insomnia.