It may not be your midnight snacks but rather your lack of sleep that's sabotaging your diet.
A study conducted at the University of Chicago found that when we don't get enough sleep, "sleep debt" changes the way our endocrine system functions. That includes our metabolism [source: Speigel]. And it's not good. Getting half of the recommended sleep -- four instead of eight hours of sleep each night -- for just six nights alters how our bodies regulate blood sugar levels and store energy so much that otherwise healthy participants suddenly began to show early symptoms of diabetes.
If you're normally getting about seven or eight hours a night, adding or subtracting about an hour won't make much of a difference. But if you're not getting more than four or five hours of sleep a day, add another two or more and kick start your weight loss.