Randomized trial finds poor sleep habits may contribute to weight gain after weight loss in obese adults.
A new study presented at this year’s European Congress on Obesity (ECO) in Maastricht, the Netherlands, finds that not getting enough, good quality sleep compromises people’s attempts to maintain weight after dieting, and suggests that about two hours of vigorous physical activity per week can help maintain better sleep.
The study was conducted by medical student Adrian F. Bogh, Professor Signe S. Torekov, doctoral student Simon BK Jensen from the University of Copenhagen, Denmark, and colleagues.
“It was surprising how weight loss in obese adults improved sleep duration and quality in such a short time, and how exercise while trying to maintain weight preserved improvements in sleep quality” , says Bogh. “Furthermore, it was intriguing that adults who don’t get enough or poor quality sleep after weight loss seem to be less successful in maintaining weight loss than those who get enough sleep.”
Over a third of adults in the UK and the United States not getting enough sleep regularly (defined as less than 6 or 7 hours a night, respectively), due to a host of aspects of modern life, including stress, computers, smart devices, and erasing boundaries of professional life.
“It was surprising how weight loss in obese adults improved sleep duration and quality in such a short time, and how exercising while trying to maintain weight preserved improvements in sleep quality. ” — Adrian F. Bogh
Not getting enough sleep or having poor quality sleep increases the risk of high blood pressure, high cholesterol and atherosclerosis (accumulation of fatty deposits in the arteries). Lack of sleep is linked to obesity, diabetes and inflammation, all of which can worsen cardiovascular disease. Sleeping too much or too little has also been shown to increase the risk of stroke, heart attack and death. It has been suggested that sleep patterns may be a contributing factor to weight regain after weight loss.
For this study, researchers analyzed data from the randomized, placebo-controlled S-LiTE trial to investigate changes in sleep duration and quality during diet-induced weight loss. A total of 195 adults (aged 18-65) with obesity (body mass index [BMI] 32 to 43 kg/m2) followed a very low-calorie diet (800 kcal/day) for eight weeks and lost an average of 12% of their body weight.
Participants were then randomly assigned to one year of weight loss maintenance with either: daily injection of placebo (49 participants), daily injection of 3 mg liraglutide weight-loss medication (49), four sessions of exercise per week (48), or a combination of both treatments (49). All members of the exercise groups were encouraged to participate in supervised 45-minute sessions, twice a week, of spinning and circuit training, and two unsupervised 30-minute sessions.
Sleep duration was measured using data from accelerometers worn by study participants before and after the low-calorie diet and after 13, 26 and 52 weeks of weight maintenance. Sleep quality was measured subjectively with the Pittsburgh Sleep Quality Index (PSQI), a self-report questionnaire. Lower scores on the PSQI indicate better sleep quality, ranging from 0 for the best sleep to 21 for the worst possible sleep. Scores above five are considered poor quality sleep.
“The fact that sleep health is so strongly linked to weight loss maintenance is significant because many of us are not getting the recommended amount of sleep necessary for optimal health and functioning.” — Sign S. Torekov
To examine the association between sleep and weight gain, participants were grouped according to their average sleep duration (less/greater than 6 hours/night) or sleep quality (less/greater than a PSQI score of 5) at randomization (after a low-calorie diet).
Researchers found that after the 8-week low-calorie diet, sleep quality and duration improved in all participants. Notably, after one year of weight maintenance, participants in the exercise groups maintained the self-reported improvements in sleep quality achieved with the low-calorie diet, while the non-exercise groups relapsed (mean difference between groups of 1 point of PSQI score).
Liraglutide treatment had no significant effect on sleep quality or duration compared to placebo.
Analyzes also showed that participants who slept an average of less than 6 hours per night at the start of the study increased their BMI by 1.3 kg/m2 during the year-long weight maintenance phase compared to longer sleepers (more than 6 hours per night).
Similarly, poor sleepers (PSQI score of 5 or greater) at the start of the study increased their BMI by 1.2 kg/m2 during the weight maintenance phase, compared to good sleepers (PSQI score less than 5).
“The fact that sleep health is so strongly linked to weight loss maintenance is significant because many of us are not getting the recommended amount of sleep needed for optimal health and functioning,” says Professor Torekov. “Future research examining possible ways to improve sleep in obese adults will be an important next step in limiting weight regain. Maintained weight loss through exercise shows promise for improving sleep”
Despite the important findings, the authors note that the study is observational and cannot prove that poor sleep causes weight changes, but suggest it may contribute.
- “Objective assessment of sleep in >80,000 UK middle-aged adults: associations with socio-demographic characteristics, physical activity and caffeine” by Gewei Zhu, Michael Catt, Sophie Cassidy, Mark Birch-Machin, Michael Trenell, Hugo Hiden , Simon Woodman and Kirstie N. Anderson, December 27, 2019, PLOS ONE.
- 1 in 3 adults don’t get enough sleep | CDC Online Newsroom | CDC
The original S-LiTE study was supported by an Excellence Grant (NNF16OC0019968) from the Novo Nordisk Foundation, the Novo Nordisk Foundation Center for Basic Metabolic Research, and a grant (NNF15CC0018486) from the Novo Nordisk Foundation Tripartite Immunometabolism Consortium. In addition, grants have been received from the Faculty of Health and Medical Sciences at the University of Copenhagen, Helsefonden, the Danish Diabetes Academy and the Department of Biomedical Sciences at the University of Copenhagen. Novo Nordisk A/S provided Saxenda (liraglutide) and placebo pens and Cambridge Weight Plan provided low-calorie meal replacements and accelerometers. None of the partners mentioned participated in or influenced the study.