Lighten Up

Calories in, calories out. What you eat and what you do. Energy balance. Isn't that what determines how much you weigh?

Not completely. It's also how you feel that determines how much you weigh.

Does emotional stress make you fatter or thinner? Both. It appears that short-term, acute stresses may help you lose weight, whereas chronic stresses cause you to put on pounds, especially around your belly, where it's most harmful.

A new study published this week in the prestigious journal Nature Medicine looked at the effects of stress on weight gain in mice. Investigators reported that chronic emotional stress turns on a peptide (chemical messenger) called neuropeptide Y, which is found in body fat.  This hormone increases appetite, especially for carbohydrate-rich foods. It also causes your body to convert these calories into belly fat, a double whammy.

What's especially interesting is that chronic stress alone didn't have much effect on weight gain in only two weeks, nor did a high-fat, high-sugar diet. However, combining both together was especially toxic and markedly increased abdominal fat deposits in only two weeks.

Over a longer period of time—three months—the high-fat, high-sugar diet caused obesity, but the amount of weight gain increased three-fold when this same diet was given to mice who were also put under chronic stress. It also caused metabolic syndrome (glucose intolerance that can lead to diabetes, high cholesterol, high blood pressure and inflammation).