Sleep diet, how proper night's sleep keeps you slim

ORLANDO, Fla. (KFSN) -- About 35 percent of adults report getting less than seven hours of sleep a night. Lack of sleep can cause daytime drowsiness and irritability, but also weight gain. A good night's sleep may be your best weapon in the battle of the bulge.

You hit the gym, you watch what you eat, you weigh yourself regularly, but what do you think is the best way to lose weight?

In a recent study, scientists found too little sleep can actually change the balance of bacteria in your gut.

In one of the largest studies to date, women who slept five hours or less a night were 15 percent more likely to become obese compared to those who got seven hours. And in yet another study, people who slept five and a half hours or less a night consumed about 385 more calories a day than those who slept seven hours or more.

Kathleen Armstrong, PhD, from University of South Florida said, "There are guidelines to follow and you have to look at both quantity and quality of sleep."

Aim for seven to nine hours a night.

To help you reach that goal, stay on a schedule. Go to bed and wake up at the same time every day, even on weekends. Keep your bedroom cool, between 60 and 67 degrees and check your mattress. It's time for a new one after about nine years of use.

So why does less sleep equal more weight? Researchers believe that too little sleep can affect hormones in your body that regulate hunger. Another theory is that you're less likely to be active if you're tired. Other studies have suggested less sleep can slow your metabolism.