Were the women who were getting less sleep also eating more?
The answer was no. In fact, the opposite was true.
“Prior studies have shown that after just a few days of sleep restriction, the hormones that control appetite cause people to become hungrier, so we thought that women who slept less might eat more,” Patel says. “But, in fact, they ate less. That suggests that appetite and diet are not accounting for the weight gain in women who sleep less.”
Understanding the Reasons
The study participants did not identify the specific factors that contribute to weight gain in women who had less sleep.
“We don’t have an answer from this study about why reduced sleep causes weight gain, but there are some possibilities that deserve further study,” Patel says. “Sleeping less may affect changes in a person’s basal metabolic rate (the number of calories you burn when you rest). Another contributor to weight regulation that has recently been discovered is called non-exercise associated thermogenesis (involuntary activity, such as fidgeting.) It may be that if you sleep less, you move around less, too, and therefore burn up fewer calories.”