Scientists are uncovering more and more evidence that insufficient sleep may cause hormonal shifts that boost hunger and appetite—particularly for fat-laden carb diet catastrophes like jelly-filled donuts and super-sized fries. “We all need to be aware there is a relationship between sleep and obesity,” says J. Catesby Ware, chief of the division of sleep medicine at Eastern Virginia Medical School, and director of the Sleep Disorder Center at Sentara Norfolk General Hospital in Norfolk, VA. Ware and his colleagues studied more than 1,000 men and women and found those who reported sleeping less also weighed more. He’s now focusing on another group of 1,000 individuals, quantifying specific daily sleep habits with preliminary data reinforcing his prior observation that less sleep equals a worse diet and a bigger body. Eve Van Cauter, a professor of medicine at the University of Chicago, recently found that when 12 healthy men in their 20s were instructed to sleep just four hours a night for two nights straight, they reported a 24% increase in feelings of hunger. What’s more, Cauter and her colleagues note that levels of the hormone leptin, which delivers the message of satiation to the brain, decreased by 18% among the men. Conversely, levels of the hormone ghrelin, which sparks hunger, shot up 28 %—prompting cravings for candy, cookies and cake. The National Sleep Foundation says that more than 70% of adults over the age of 18 get less than eight hours of sleep a night on weekdays–and 40% get less than seven hours. Experts recommend most people get between seven and eight hours of sleep nightly to be at the lowest risk for weight gain.
