The connection between gallbladder disease and weight stems from the fact that being overweight increases the body's production of cholesterol. With the body making cholesterol, the liver excretes more. This raises the level of cholesterol in bile, which leads to gallstones.

The link between cancer and excess weight is not as strong as with the diseases above, but a link does exist. Being overweight increases the risk of endometrial cancer, in particular, although cancers of the gallbladder, bile duct, ovary, breast (in postmenopausal women), cervix, colon, and prostate are also more common in overweight people.

We are a nation that weights too much, and we seem to know it—a 1985 Gallup poll found that almost 90 percent of U.S. adults believed they weigh too much. As a result, dieting has become a major preoccupation with millions of people in the United States. The same poll found that 31 percent of the women questioned dieted at least once a month, and 16 percent of the women considered themselves perpetual dieters. Other studies have identified even greater numbers of dieters in the U.S. population.

One reason why there are so many people on diets is that most dieters regain the weight they lose. In fact, between 60 and 90 percent of the pounds shed on diets in this country are put back on. To lose these pounds, people go back on diets, and soon a cycle develops—gain, diet, lose, gain, diet, lose, and so on.

The effects of the diet cycle are unclear, but there is some evidence suggesting that it is not a healthy activity. For example, several studies have found that people who gain and