In the past few years, the government and health agencies have issued somewhat varying "healthy diets" that may help prevent heart disease and cancer. Each diet is a bit different from the others.

With the guidance of the American Health Foundation, several nutritional scientists and an old Mixmaster, I blended all the advice into these "12 Rules for a Healthier Body." To Prevent Both Heart Disease and Cancer

Fats and Oils: Go light on both and especially avoid "saturated" fats (those in meat and dairy products), as well as fatty foods such as standard salad dressing and pastries (usually loaded with fat or oil). Eat poultry, fish and, in moderation, leaner meats such as round steak, lean ground beef, lean stew meat, leaner pork, veal and lamb, trimming visible fat. When fat is necessary, use soft margarine or a modest amount of vegetable oil (corn, cottonseed, safflower, sesame, soybean or sunflower seed). Fiber or Roughage: Eat more bran, whole-wheat bread and muffins, whole-grain cereals, oatmeal, potatoes in skins, yams, squash, beans, soybeans, bean curd (tofu), peas, lentils, carrots, other vegetables and fruits, especially apples and others with skins, also bananas, peaches, plums, grapes, berries, barley, buckwheat, brown rice, seeds. Add a little at first (until your intestines get used to them), then more and more. Calories: Obesity has been implicated in both cancer and heart disease. Eat filling foods, but eat less, unless you are underweight. Complex Carbohyrates: Eat the often unfairly damned "starches," such as potatoes, pasta and many fruits, which actually have less than half as many calories as fats. But don't swamp them in fats; learn to season lightly and savor. Exercise: Vigorous exercise may increase the proportion of high-density lipoprotein (HDL), a kind of "healthy cholesterol" in the blood. Even a little exercise burns some calories, and a little exercise every day burns a lot of calories. To Prevent Heart Disease

Cholesterol-High Foods: Limit egg yolks to no more than three a week, and cut down on organ meats such as liver, kidneys and sweetbreads. Fruits and Vegetables: Eat fruits and vegetables (fresh or frozen) close to their natural state and unadorned, rather than with creams or sauces.Salt: Stop salting most food (you'll be surprised how soon oversalted food will not taste good) and avoid foods and seasonings loaded with salt. Too much sodium may trigger high blood pressure in susceptible persons, which in turn may help cause strokes and heart disease. To Prevent Cancer

Greens and Yellows: Eat dark green leafy vegetables and yellow fruits and vegetables (such as carrots and winter squash) for vitamin A. Also, citrus fruits and tomatoes to supply vitamin C. Foods are better, safer sources of vitamins than high-dose supplements. Eat crucifers (such as cabbage, broccoli, brussels sprouts, kohlrabi and cauliflower), which may contain anti-cancer elements, as well as fiber. Pickled/Preserved/Smoked/Cured: Go light on meats or fish that have been pickled, preserved, smoked or cured, including salt-, smoke- or nitrate-cured ham, bacon, sausages, weiners, salami and other cold cuts. They tend to be loaded with salt, sugar, fats and chemical preservatives. For Good Health in General Sugar:

Go light on pastries and sweets. Too much sugar encourages tooth decay, fills you up with empty rather than body-building calories and gives you a quick energy fix that may be followed by a worse letdown. Alcohol: Keep any alcohol use moderate. Some population studies give tantalizing evidence that a drink or two (or one or two beers or glasses of wine) may help prevent heart disease. But there is also some evidence that even moderate drinking may slightly increase the risk of cancer and high blood pressure. Also, one drinker in 10 may become alcoholic. I'd say: Know yourself and your whole health status. Some people can drink modestly and enjoyable without huge risk. Some cannot.