Those of us providing front-line care for Americans -- nurses, physicians' assistants, pharmacists -- have a perspective that differs from the bureaucratic physicians in the American Medical Association and other specialist organizations, because we literally have our fingers on the pulse of Americans. And a lot of us have come to realize that most medical problems are brought on by the failure of humans. Human metabolism is not that far evolved from the Stone Age and is better geared toward surviving famine than it is to the current abundance of high-calorie food and the pervasiveness of passive activity. Obesity and lack of exercise are behind many common diseases. Type 2 diabetes, which leads to heart disease, vascular problems, hypertension, kidney failure and erectile dysfunction, is at epidemic proportions and is primarily a disease of the obese. And we're seeing the problem in younger and younger people. An article in the Journal of the American Medical Association this spring delineated how excessive weight gain in the first three months of life is associated with cardiovascular disease and Type 2 diabetes in early adulthood. Yet, for many reasons, exclusive breast-feeding, which often prevents early and dangerous weight gain, just doesn't happen much in our country. Another article this summer concluded that a diet high in fruits, vegetables and nuts and relatively low in meat (a 'Mediterranean' diet), coupled with physical activity, was associated with a reduced risk of Alzheimer's dementia. Many common types of cancer also strike the inactive and the obese at a higher rate. Among the patients I treat are some who work in the fields of California's San Joaquin Valley, and I am intrigued by them. Although their genetic inheritance makes them a target for high cholesterol and joint pain, and of course diabetes, they don't tend to get those conditions often -- at least not until they stop working in the fields. Many of the factors leading to inactivity and obesity are societal. For example, the mother who picks up hungry kids from day care after working eight hours can be very tempted to stop at a fast-food outlet on her way home. In the old days, evening walks and chats with neighbors used to satisfy people's evening leisure needs, but now we use TVs and computers instead. I would estimate that something like 50 percent to 70 percent of my patients' medical costs would be eliminated (not reduced -- eliminated) if their diets and exercise regimens were optimized. But the government seems to be working on the other end of the problem, not taking direct input from actual health-care providers. Motorized scooters are provided free to morbidly obese patients with weight-dependent arthritis, when the best remedy for these people would be to ambulate through their pain or avoid excess weight gain in the first place. School lunches are often made up of very fattening, but tasty, food. The examples are endless. So how do we save money on health care? We need to get out the old carrot and stick. How about a tax credit for those with a body-mass index (measure of weight to height) of less than 26? Or for mothers who exclusively breast-feed for the first four months of their baby's life? Or a credit for documented miles on a treadmill or a bicycle? Or a tax on fattening foods with little nutritional value, as others have suggested? Barring genetic or catastrophic disease, accidents and maybe the aging process itself, our health is in our hands. Promoting knowledge about and adherence to healthy lifestyles is still the best way to cut down on health-care costs. After all, Big Brother can only do so much. Schlaerth is an associate professor of family medicine at Loma Linda University School of Medicine in Loma Linda, Calif. 