A new study published in JAMA Internal Medicine connects short sleep duration and obesity. A randomized controlled trial was conducted from Nov, 2014 to October, 2020 involving participants between the ages of 21 and 40. All of them had a body mass index (BMI) between 25 and 29.9 and had a sleep duration of less than 6.5 hours per night. An intervention was tested to see if improving sleep duration impacted their energy intake, energy expenditure and body weight.
What did the researchers do?
210 participants were randomized to either a control group or an intervention group. The intervention group involved individualized sleep hygiene counseling with the goal of extending their nightly sleep duration to 8.5 hours per night. No one was told to change their diet or daily exercise routine.
Every study is powered for a primary outcome. The primary outcome here was change in energy intake from baseline. This was assessed using the total energy expenditure and the change in body energy stores. The doubly labeled water method was used to measure total energy expenditure. Change in body energy stores was measured using daily home weigh-in measurements and body composition changes from x-ray absorptiometry. Changes in sleep duration were assessed by actigraphy, meaning participants wore an accelerometer, or motion-based monitor, on their wrists each night. The accelerometer had a button they pressed each night when they went to bed and then again when the woke in the morning. An intention-to-treat analysis was used to compare the control group with the intervention group. For folks who don’t know, an intention-to-treat analysis just means they analyze data by the treatment group one is assigned to regardless of whether or not he/she received or completed the treatment. (Or in this case, the behavioral intervention.) Participants were followed for 4 weeks.
Participants in the intervention group had a significant increase in mean sleep duration compared to the control group (1.2 hours). No difference in sleep efficiency (time asleep during time in bed) was found between the groups. Energy intake significantly decreased for the intervention group compared to the control group. For all participants, the change in sleep duration was inversely associated with the change in energy intake. (Each 1-hour increase in sleep duration was associated with a decrease in energy intake of 162 kcal/d.). A statistically significant difference in energy expenditure was not found. From baseline, the control group gained weight (.39 kg), and the intervention group lost weight (a reduction of .48 kg). There were no significant differences found in baseline characteristics.
Take-Home Point for Short Sleep Duration and Obesity:
As the authors noted in the discussion section of the paper, the study was the first to describe the effects of extending sleep on energy intake and body weight. This is a cost-effective, holistic lifestyle modification that anyone can do right at home to get to a healthier weight and perhaps help curb our obesity epidemic. The study supports the notion that short sleep duration and obesity are linked. At the least, someone struggling with his/her weight might consider his/her sleep habits. How are you sleeping? Do you get enought sleep at night? While the authors didn’t explain why an increase in healthy sleep leads to eating less, lots of people eat more when they are tired. Being tired can also lead to chronic stress which can impact metabolism and lead to unhealthy weight gain.
I’ve made it a goal this year to write more blogs and do more podcasts about obesity, the opioid epidemic and industry’s influence on healthcare and public health policy. Obviously, this blog is an update on new obesity research. If you are interested, in addition to “Short Sleep Duration and Obesity” please consider these:
(I also did a podcast with the lead researcher. You can listen to that here.)
(I did a podcast with that lead researcher too. You can listen to the podcast here.)