Lighten Up

When the researchers blocked the effects of neuropeptide Y, it reduced stress-induced visceral (belly) fat by 50 percent "without any discernible effect on food intake, which remained as increased as it was" according to the investigators.

In other words, they ate the same amount of food, didn't exercise more, yet their belly fat decreased by half when the effects of neuropeptide Y were blocked. This is amazing stuff.

What about humans? A major study published last month in the American journal Epidemiology followed almost 7,000 men and 3,500 women over a 19-year period. The investigators found that there was a direct relationship between work stress and risk of general obesity (body mass index greater than 30) and central obesity (waist circumference greater than 40 inches in men and 35 inches in women, the kind that is the most harmful) that was largely independent of other factors.

So, the more stressed people felt, the more belly fat they accumulated.

In a 2002 study in Sweden, anxiety and depression were also found to increase the risk of obesity. Insulin and blood-sugar levels were higher in those who were anxious and depressed.

Neuropeptide Y may also be a common pathway with other chronic diseases, including coronary heart disease and diabetic retinopathy. It also stimulates growth of new blood vessels, called angiogenesis. This contributes not only to weight gain but also to cancer and may help to explain the relationship of obesity to increased cancer risk.