May 10, 2022
"Our results show that there are a lot of variables that impact the regain of weight lost," said Signe Torekov, PhD, from the University of Copenhagen, Denmark, who presented the findings at the European Congress on Obesity 2022 during a press conference and as a poster.
Asked to comment, Christopher E. Kline, PhD, of the University of Pittsburgh, Pennsylvania, said the findings "do raise the possibility as to whether intervening upon sleep after weight loss would help maintain the weight loss," although he added the results were a secondary analysis of a study, and so causality could not be inferred.
"What's interesting is that it's not always duration that is the dimension of sleep most strongly associated with better weight loss," he told Medscape Medical News, commenting on the fact that exercise seemed to improve sleep quality most of all.
A 2021 study that he conducted found that individuals' timing of their sleep and the regularity of their morning wake time were the strongest predictors of weight loss — not the duration of sleep.
Ihuoma Eneli, MD, of the Center for Healthy Weight and Nutrition at the Nationwide Children's Hospital, Columbus, Ohio, said, however, that both duration and sleep quality need to be taken into consideration.
"In the field of obesity, we recognize that along with diet and physical activity, sleep is a key behavior that needs to be addressed in any intervention. In our center, we ask questions on sleep including duration and quality, including how many times the patient wakes up during the night, as well as sleep hygiene," she said.
Does Sleep Quality or Quantity Make the Difference?
Data were drawn from a secondary analysis of the S-LITE trial, a randomized placebo-controlled study in which 195 adults with obesity (body mass index [BMI], 32-43 kg/m2) followed an 8-week, 800-calorie/day diet and lost an average of 12% of their body weight.
Participants were then randomized to a 12-month weight loss maintenance program of placebo injection (49 participants); daily 3-mg injection of the GLP-1 agonist liraglutide (49); four exercise sessions per week (48); or a combination of liraglutide plus exercise (49).
Accelerometers were used to assess sleep duration before and after the low-calorie diet, and at 26 and 52 weeks of weight maintenance, while the Pittsburgh Sleep Quality Index (PSQI) questionnaire was used to measure sleep quality at screening, baseline, and study end.
After the initial weight loss, participants were grouped according to their average sleep duration (below/above 6 hours/night) or sleep quality (below/above a PSQI score of 5, with above 5 signifying a poor sleeper).
Results after the low-calorie diet part of the study showed sleep quality and duration improved by 0.8 global PSQI score and 17 minutes/night (P < .0001), respectively.
Then, after 1 year of the weight loss maintenance phase, participants in groups with exercise maintained the sleep quality improvements achieved from the low-calorie diet, while those in the non-exercise groups lost some of the benefit gained (average between-group difference: 1 PSQI score point; P = .02).
Liraglutide treatment had no significant effect on sleep quality.
Regarding sleep duration, after 1 year of the weight loss maintenance phase, BMI increased by 1.4 kg/m2 in participants with less than 6 hours/night of sleep compared to those with 6-7 hours/night of sleep (P = .02).
Sleep duration was not affected by exercise or liraglutide.
People who had poor quality sleep also increased their BMI by 1.2 kg/m2 (P =.01) compared with good sleepers during the 1-year maintenance phase.
The original S-LiTE study was funded by grants from the Novo Nordisk Foundation. Grants were also received from the University of Copenhagen and Danish Diabetes Academy. Novo Nordisk supplied Saxenda (liraglutide) and placebo pens and Cambridge Weight Plan supplied low-calorie meal replacement products and accelerometers. Torekov has reported receiving a grant from Novo Nordisk. Kline and Eneli have reported no relevant financial relationships.
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