There is a growing body of evidence to suggest that if you are not getting enough sleep each night you are going to put on weight. In fact many researchers now believe this is a major factor in the current obesity epidemic that is sweeping the western world.
Anyone who is chronically sleep-deprived may have continuous cravings, an insatiable appetite and associated ravenous food consumption. This is not necessarily associated with low blood sugar levels but using functional MRI, the areas of the brain associated with hunger, food cravings and food seeking, light up like a christmas tree when sleep-deprived subjects are shown food images.
Last month a Swedish study with 12 normal-weight male subjects showed that a night of total sleep deprivation resulted in increased activation of the right anterior cingulated cortex and an increase in hunger. The Journal of Clinical Endocrinology & Metabolism March 1, 2012 vol. 97 no. 3 E443-E447
This is not just a short-term affect. Another study showed that when thirty healthy men and women were given 4 hours or 9 hours sleep each night over a 2 week period, those with the shortest sleep span were most susceptible to over-eat. Those areas of the brain associated with hunger, hightened awareness of the reward value of food and the decision making, cognitive processing, motivation and centres of the brain related to the desire to seek food were highly activated in the restricted sleepers. Am J Clin Nutr 2012; 95: 818-24 (see activated brain centres below from fMRI after visual stimulation by Uni Minnesota).
If you are having problems moving those extra kgs of fat from around the middle, try sleep therapy.