The Food Guide Pyramid is just an outline of what you should eat; it’s up to you to fill in the details. That’s both good and not-so-good news: good because it means you can choose from a whole world of foods instead of settling for some rigid regimen, and not-so-good because it means you need to think about what you’re going to eat.

  Every time you walk into the grocery store or sit down at a restaurant, you have to decide what you should, and want to, feed your body. Once you familiarize yourself with the smart choices in each food group, however, opting for healthy foods will become second nature.

Bread Cereal, Rice, and Pasta Group

This group sits at the bottom of the food pyramid for a reason: Complex carbohydrates are the foundation of a healthy diet.

  The stars of this category are whole grains. Most famous for their fiber content, they also contain a range of substances that researchers believe are important to health—substances that are removed from refined grains during processing. Whole grains are rich in vitamin E and other antioxidants—some of which are unique to grains—that may help fend off heart disease and cancer.

  They also contain compounds that help lower the risk of breast cancer and colon cancer, and researchers believe that a diet rich in whole grains may help prevent adult-onset diabetes.

Fruit and Vegetable Group

  The more fruits and vegetables you eat, the better. Not only will you load up on vitamins, minerals and fiber but you’ll fill up on low fats, low calorie foods rather than the other kinds. It’s all well and good to espouse “everything in moderation,” but there are times when you crave more a big, heaping bowl or plateful of something. On top of their many other attributes, fruits and vegetables have something going for them that no other food group can claim: You can pretty much eat as much as you want! When you are trying to healthy-up and thin down—worrying about portions and fat content and the rest—this news comes as a considerable relief.

  Not only can you eat lots of fruits and vegetables, you must, if you want to be healthy as well as trim. Even when you’re cutting calories, you should never skimp on these two food groups. You’ve probably seen the National Cancer Society’s “Eat Five a Day” posters and signs and stickers in your supermarkets produce section. The big push reflects the fact that vitamin- and fiber-rich fruits and vegetables can help reduce the risk of some cancers, heart disease, and other ailments as well as birth defects. There’s simply no better source for nutrients.

Some general rules to remember:

• Look for produce that’s rich in vitamins A and C, which can help reduce die risk of some cancers and heart disease.

• Choose fruits and vegetables in a wide range of colors to get maximum nutrients.

• Don’t get all your fruit servings in juice form; whole fruit gives you fiber as well as vitamins.

Dairy Group

  Foods in the dairy group provide two ingredients that are necessary to a strong, healthy body: protein and calcium, the mineral that’s so important for maintaining your bones as well as for regulating your heartbeat, your blood pressure, and nerve impulses.

  Unlike fruits and vegetables, however, dairy foods should be eaten in moderation, since they often feature fat along with ah that good calcium and protein. Look for low-fat or nonfat versions.

Protein Group

  Protein foods supply your body with substances needed to build and repair muscles and other tissues. Animal sources provide iron, which helps carry oxygen to muscles, and zinc, which can strengthen your immune system; vegetable proteins offer the added benefits of vitamins, minerals, and fiber.

  Most Americans already get more than enough protein in their diet—it’s the one food group people don’t skimp on—and often the least healthy kinds of protein. The challenge is choosing protein sources that are high in protein but low in unhealthy fats: beans, fish, poultry, and lean meats rather than marbled steaks and fatty lunch meats.