Last month scientists reported the discovery of the "mahogany gene," which may be important for weight control. The mahogany-colored mice that have a defect in this gene remain slim even if they're fed a high-fat diet. Since 1992, scientists have found five genes that affect the weight of mice. I find this research very exciting. We're beginning to understand why some people gain easily, while others just as effortlessly maintain a normal weight. Someday these findings could lead to helpful medications - but I don't expect a single "magic bullet." Our body weight is controlled by multiple mechanisms whose functions overlap. For instance, we experience hunger when our stomach is empty and contracts. However, we also get signals from blood sugar levels, from secretion of cholecystokinin and other intestinal hormones, from release of serotonin and other brain chemicals. So even if we gain control over one factor, others can step in to override it.

Talk to your doctor about medications - there are some wonderful new drugs for osteoporosis. One, Evista, seems to protect against heart disease and breast cancer too.

Another important point: Medication can never replace a healthy lifestyle. Wholesome food promotes our health in ways that go beyond weight. Similarly, vigorous physical exercise improves our muscle strength and cardiovascular fitness - and also enhances mood, self-esteem and body image. So stick with those positive changes! They're important to your well being, regardless of your genes.