Clinical Trial Shows Relationship Between Sleep and Weight Loss

Unhealthy lifestyle habits such as not getting enough sleep or physical activity are known to increase the risk of obesity and overweight.

But it is unknown whether increasing sleep duration can reverse or prevent obesity. As a result, researchers are interested in whether adequate sleep can be an effective long-term weight strategy for obese and overweight people. In pursuit of this, a recent randomized clinical trial (RCT) was carried out to evaluate the relationship between adequate sleep and weight loss.

The Randomized Clinical Trial

As mentioned earlier, an RCT was carried out to investigate how sleep extension affects energy intake and, consequently, weight loss. The trial was sponsored by grants from the National Institutes of Health and the Diabetes Research and Training Center at The University of Chicago.

Overview of the clinical trial

A total of 80 overweight adults were enrolled for the trial. All participants’ body mass index (BMI) was between 25.0 and 29.9 (calculated as weight in kilograms divided by height in meters squared), which is the range for overweight. The participants also slept for less than 6.5 hours at night.

Half of the participants were asked to maintain their usual sleep routine. In contrast, the other half received individualized sleep hygiene counseling intending to increase their sleep duration to about 8.5 hours during the 2-week trial.

The energy intake of the participants was calculated from the sum of total energy expenditure. The popular and accurate doubly labeled water method was used to determine total energy expenditure ( 3 ).

Results of the clinical trial

Participants who could extend their sleeping time ate less with their average calorie intake reduced by 270 kcal/d (kilocalories per day). Some group members reduced their calorie intake by up to 500 kcal/d. Those in the control group ate more, with their calorie intake increasing by an average of 114.9 kcal/d. Each 1-hour increase in sleep resulted in about 162 kcal/d reductions in energy intake.

The sleep extension group also experienced significant weight loss, with 1.9 pounds lost on average. Some members of the group lost up to 3 pounds. On average, members of the control group gained about 0.86 pounds, with some members gaining as high as 1.7 pounds.

Limitations of the study

While the energy intake of the sleep extension group decreased, it’s unclear whether they ate less of certain foods or smaller portions overall, as the researchers didn’t track what they ate. Also, the timing of the meals is unknown.

Furthermore, the trial provides no information on how to maintain healthy sleeping habits in the long term after managing to improve the sleeping habits of half of the participants.

Does sleep affect weight loss? Conclusions from the RCT

The trial’s results clearly showed that sleep extensions could help obese and overweight people lose weight, especially those known to habitually curtail their sleep duration. So, there is a definitive relationship between sleep and weight loss. The Hall Dynamic Predictive Model, predicted that sufficient sleep could lead to a weight loss of about 26 pounds over three years if an energy intake reduction of 270 kcal is maintained.

The weight-loss potential of sufficient sleep becomes more impressive when one considers that the participants didn’t change any other aspects of their lifestyle. They only had to go to bed earlier than they used to and gain about 1.2 hours of sleep, more than their usual sleep time.

This highlights the importance of promoting sufficient sleep not only as a means of preventing obesity but also as an effective method of healthy weight maintenance. Getting enough sleep is also bound to be included in weight-loss programs as more research explores its weight loss potential.

Extended sleep, exercise, and diet could be a potent combination to conveniently and effectively lose weight in the long term.

Getting a good night’s rest

With sleep quality and quantity declining over the past decades, it’s more important than ever to make conscious efforts to get adequate sleep. The key to a good night’s rest is to put away all electronics. Electronics like phones and laptops emit blue light that powerfully suppresses the release of melatonin, the hormone that signals the body to sleep ( 4 ).

Alcohol and caffeine intake late in the evening can also affect sleep duration due to their stimulant effect on the central nervous system (CNS). It’s also worth mentioning that a big meal two or three hours before bedtime can affect sleep ( 5 ).

A sleep schedule is also essential to getting a good night’s rest. Going to bed and waking up consistently reinforces the body’s sleep-wake cycle ( 6 ). A typical adult needs at least 7 hours of sleep, with 8 hours enough for most people to be well rested ( 7 ).