For health-conscious cooks who refuse to sacrifice flavor, mastering how to make and use marinades is essential.

It's an excellent way to infuse vibrant flavors into lean meat, poultry and fish without adding excessive fat or salt.

Most marinades follow a basic equation that calls for a bit of acid, a bit of fat and flavorful ingredients such as onions, garlic, fresh or dried herbs, and spices.

Some people believe the acid — which often takes the form of lemon juice, vinegar, wine or buttermilk — helps break down tough proteins or connective tissue in the meat, theoretically acting as a tenderizer. Meat expert Bruce Aidells isn't so sure.

He says there is much debate over whether this is true. Marination certainly can change the texture of a meat, but some people argue it makes it mushy rather than tender. Nevertheless, Aidells is a big fan of marinating.

"My motivation for using a marinade isn't texture," he says. "I like to be able to take a cheaper cut of meat and infuse it with intense flavor that might otherwise be missing."

The fat — generally a cooking oil such as olive, canola or even nut oils — helps with that. Oil spreads the flavor throughout the solution and helps it coat the food, keeping it moist. The oil also makes for better browning during cooking.

When using marinades, it's important to keep several guidelines in mind.

Once the marinade is mixed, set aside a portion before adding the meat to it. This portion can be used for basting or drizzling over the meat after cooking.

Don't be tempted to baste or drizzle with the marinade the raw ingredients soaked in. Doing that can transfer harmful bacteria from the uncooked food. To use the soaking marinade, transfer it to a saucepan and boil for at least 5 minutes to kill any pathogens.

Marinating should be done in a stainless-steel or glass container, or a zip-closure plastic bag. If the marinade doesn't cover the food, be sure to turn the meat occasionally to ensure even flavoring.

As a rule of thumb, seafood should not be marinated more than 30 minutes to an hour, as the tender flesh can be ruined.

Poultry and vegetables can marinate up to eight hours, depending on the flavor intensity desired. Longer soaks can produce chicken that bursts with flavor, but as with any protein, marinating more than 24 hours can change the texture in an unpleasant way.

Red meats almost always benefit from at least an overnight marinating.

Spicy lemon chicken from Dr. Fedon Alexander Lindberg's upcoming book "Eating the Greek Way," (Clarkson Potter, June 2007, $25) is a fine example of a healthful marinated dish that yields moist and flavor-packed results.

Chicken drumsticks and thighs (an excellent source of iron) have the fatty skin removed before being soaked overnight in a lemon-based marinade spiked with hot chili sauce. Sambal oelek (Indonesian chili sauce) can be found in the Asian section of most grocers. Otherwise, any Asian chili sauce can be substituted.

SPICY LEMON CHICKEN