Sleep and Your Diet

If you struggle with your weight, here’s another reason to make sure to get enough sleep at night. A recent study found that cutting back on sleep reduces the benefits of dieting.

Researchers at the University of Chicago’s General Clinical Resource Center followed 10 overweight but healthy volunteers aged 35 to 49 with a body mass index ranging from 25 (considered overweight) to 32 (considered obese). The participants were each placed on an individualized balanced diet, with calories restricted to 90 percent of what they needed to maintain their weight without exercise. The researchers studied each participant once for 14 days in the lab with an 8.5-hour period set aside for sleep, and once for 14 days with only 5.5 hours for sleep. While they were awake, participants spent their time engaged in home- or office-like work or leisure activities.

The volunteers lost about 6.6 pounds during each 14-day session. During weeks when they got adequate sleep, they lost 3.1 pounds of fat and 3.3 pounds of fat-free body mass, mostly protein. When they did not get enough sleep, they lost about 1.3 pounds of fat and 5.3 pounds of fat-free body mass. The researchers also found that getting enough sleep helped control the dieters’ hunger.

The authors of the study say it sends a clear message to people trying to lose weight: don’t ignore the way you sleep when going on a diet. Getting enough sleep could boost the beneficial effects of a diet, while not getting enough sleep could defeat the purpose.