With so many fad diets out there, it's difficult to know which one is the healthiest or which one will keep you in the best shape.

Some experts say skip those fad diets altogether and create your own with the foods you like. But first, you need to know what foods are the power players.

"There's a real connection between what you eat and how healthy you are," said Ellen Haas, a food and nutrition expert with the FoodFit Company in Washington, D.C.

On the top of the list of fit foods are blueberries. They're rich in anti-oxidants, which means they're cancer fighters. Tomatoes, peppers and broccoli also fight cancer. Then, grab the greens.

"Leafy greens are essential to everyone's diet. They're rich in vitamins, they're high in fiber and they're really important in helping to fight against cancers, to fight against heart disease," Haas said.

Also, don't forget the fish. Sardines, tuna and salmon are the "A" players. Keep in mind that wild salmon has less chance of contamination.

Next, you need nuts.

"Walnuts and almonds are both the healthier nuts," Haas said.

They both protect against heart disease. Haas said meat is also a key member of the fit and food group. Just be careful how you choose your beef.

Look for the select grade. It means that it's a lower fat grade that may be a little less expensive, but it has all the health benefits that other key foods include garlic, acorn squash, eggplant, zucchini and sweet potatoes.

"You need it all in order to be healthy," Haas said.

Once you know what foods should be in your grocery cart, it will be easier to get cooking and get fit.

Under President Clinton, Haas was the chief nutrition official in the federal government.

Her book, Fit Foods, highlights simple recipes that use the most powerful foods to get your body in the best shape.