Do you remember your Grandmother telling you to “get your beauty rest”? Or Ben Franklin’s saying “Early to bed and early to rise makes a man healthy, wealthy and wise.”? It might turn out that they were a lot closer to the truth than we ever gave them credit for. Every couple of months recently there has been another report of some study showing that not getting enough sleep could be making us fat!

Now I admit that when I first heard that, my reaction was “Yeah, right!” I thought that if anything I should be spending less time in bed and more time up and moving. But the research is saying just the opposite. More people who sleep less than 6 hours a night are obese than those who sleep between 7 and 8 hours a night. If you sleep more than 9 hours a night, your chances of being too heavy go up again.

This is not just connected to weight. Several large studies in several countries around the world all found that people who regularly got about 7 to 7 ½ hours of sleep a night were the most likely to live the longest. People who get too little sleep on a regular basis or who have a hard time falling asleep or staying asleep through the night, are more likely to get diabetes later in life. Even small children have been studied. Two year olds who got less than 6 hours of sleep a night were much more likely to be overweight by the time they were 7 years old than the children who got more sleep! Lack of sleep seems to change the way our hormones control our bodies and our reaction to food, hunger and exercise for the rest of our lives.

How can this be possible? What can sleep have to do with weight? To the surprise of even the researchers, the answer seems to be “A lot”. There are a lot of questions still to be answered. But here’s what they understand about what’s happening so far.

There are at least 2 hormones that have a lot of effect on our appetites. One of them is made in our fat cells. Its job is to tell the brain when we are full. It shuts off the hunger signals to our brain. There is another hormone that is made in our stomachs. Its job is to tell the brain when the stomach has been empty too long. It sends hunger signals to the brain to tell us to eat.

The surprising thing is that when we don’t get enough sleep our bodies make less of the “I’m full” hormone and more of the “I’m hungry” hormone. So whether we’ve eaten a lot or not, just not sleeping can make us feel hungry! And, that “I’m hungry” hormone, when it starts working, makes us especially hungry for high calorie, starchy and sweet foods! Those are all the things we don’t need to be eating much of!

Sleep also affects our insulin levels and several other hormones that help control blood sugar and blood fat levels. What we are doing when we are not asleep affects our weight too. If you don’t get enough sleep you wake up tired. If you begin the day tired you are less likely to exercise during the day. Less exercise helps keep the pounds on.

If you are watching TV or playing video games instead of sleeping, what else are you doing? Many people are eating! A bag of chips, a dish of ice cream in front of the TV, a package of cookies beside the computer, those calories add up. Those are exactly the foods you are likely to crave if you haven’t gotten enough sleep.

So Grandma was right when she called it “beauty rest”, and Ben was right about making you healthy. Getting your sleep, between 7 and 8 hours of it a night, is likely to help keep your weight in the healthy range and your appetite under control. If you’re trying to stick to a diet, get yourself to bed at a reasonable hour!