Stress has a multitude of physiological effects, including increased weight gain. Stress is the physiological representation of the body failing to respond to real or imagined threats. Such effects can include clenched jaw, tight neck and back, mood changes, and also biochemical changes. These biochemical changes can be positive or negative, and are controlled by the hypothalamic-pituitary-adrenal axis (HPA). When triggered, the HPA axis releases various hormones, including the “stress hormone” cortisol.
The release of cortisol causes blood sugar and blood pressure to increase. Current theories suggest that high levels of cortisol are a factor in weight gain, particularly in belly-fat. The exact relationship between stress and weight gain is still being researched. What is known currently is that lack of sleep increases cortisol levels, which causes an increase in appetite. Other studies have concluded that cortisol levels serve as a means of predicting weight gain. Another study conducted in December of 2008 at the University of Oregon found a connection between cortisol levels and weight gain at a genetic level. One other correlation that has been found is that when people are stressed, they are less likely to follow a proper, normal diet, possibly adding to the connection between cortisol and weight gain.
Cortisol has amazing effects throughout the body. It is important to note that such things as a lack of sleep can seriously alter your eating habits. It is certainly surprising to learn this type of correlation has been made scientifically, because there are so many more lay-men explanations for weight gain (psychological problems, not eating healthily, not exercising enough, etc). Perhaps this knowledge can potentially help fight obesity in the future?
Sygo, Jennifer. "Which came first, the belly or the stress?" National Post 26 Jan. 2009. 15 Mar. 2009