While we have known that there is a link between sleep and weight, the exact link and mechanism has been unclear.

If you are deprived of sleep, you will be less alert and your thinking skills will be reduced as well. In this week's issue of the Annals of Internal Medicine is an article exploring the so called molecular mechanism between sleep and obesity, diabetes and other health problems. 

All cells including fat cells need sleep to function properly body fat or adipose tissue stores energy and releases energy. When these cells are in the storage mode, the fat cells remove fatty acids and lipids (other kinds of fat) from the circulation and therefore protect tissues. When fat cells can't respond to insulin which drives the storage, the reverse happens with fatty acids and lipids going into the circulation.

In this recent study lean healthy adults underwent 2 study conditions at least 4 weeks apart. In one they spent 4 nights at 8.5 hours in bed. In the other the sleep period was reduced to 4,5 hours for 4 days. Of paramount importance is that food intake was strictly controlled and identical in each study.

On the morning after the end of each study period all had a glucose tolerance test which measures how well insulin works. They also removed fat cells and measured how the fat cells responded to insulin.

After only 4 nights of short sleep, total body insulin response decreased b why an average of 16% but the insulin sensitivity of fat cells decreased by 30 per cent. That is like the difference between cells from obese people versus lean people or diabetics and non-diabetics!

While we think we can still function on little sleep, our fat cells can't and this can lead to adverse metabolic consequences. It suggests we can use sleep like diet and exercise to prevent weight gain!