How about an extra big brownie or hot fudge sundae every day? That’s the equivalent of the extra food people eat after getting too little sleep the night before, a new study shows.
No wonder people who sleep six or fewer hours a night are more likely to gain weight over the years than those who sleep seven or eight hours a night!
Among the 68,000 women in the Nurses’ Health Study, for example, those who reported that they slept six hours a night gained 1½ more pounds over a 16 year period than those who reported sleeping seven hours. Those who said they slept five hours or less a night gained roughly 2½ more pounds.
Why the extra weight?
One major explanation: we eat more the next day if we don’t get enough sleep.
“There’s substantial evidence from experiments in people that sleep deprivation leads to an increase in food intake,” says Marie-Pierre St-Onge, a sleep and obesity researcher at Columbia University in New York.
In a study of hers a few years ago, 30 people in their 30s and 40s ate an average of 300 more calories after being limited to about four hours of sleep a night for four nights than they did when they could sleep as long as they wanted to for four nights.
Now researchers in the United Kingdom have confirmed the effect of too little sleep with a new meta-analysis.
They pooled the results of 10 earlier clinical trials, including St. Onge’s, that varied the sleep time of more than 160 men and women for a few days to a week. Some nights the participants got a full night’s sleep, other nights usually five hours or less. The researchers then monitored how much food they ate during the next 24 hours.
The average number of extra calories the participants ate the day after getting too little sleep compared with the days after getting enough sleep was 385 calories. They got those extra calories by choosing fattier foods than they normally would eat.
That’s the equivalent of eating an extra Starbucks Double Chocolate Chunk Brownie (380 calories) or a McDonald’s Hot Fudge Sundae (340 calories) every day! In addition to regular meals and snacks.
Why might sleeping less make people eat more?
“Studies find that depriving people of sleep raises their blood levels of ghrelin, a hormone that increases appetite, and lowers their blood levels of leptin, a hormone that inhibits appetite,” says sleep anthropologist Kristen Knutson of the University of Chicago.
Gerda Pot, who led the meta-analysis at King’s College London, cautions that we don’t know yet if people who miss just a little bit of sleep will eat more the next day or whether people continue for years to eat extra calories after regularly getting too little shuteye.
Source: Eur. J. Clin. Nutr. 2016 Nov 2. doi: 10.1038/ejcn.2016.201.
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