Just like Mom always said, meat is an excellent source of protein. And what was good for you when you were growing up is still good for you now that you're growing older.

Our bodies use the protein in meat and other high protein foods to make amino acids. These substances help our bodies make their own proteins, which are used to regulate hormones, grow new tissue, and repair or replace worn out tissue.

Unfortunately, meat tends to be high in saturated fat. So you may be wondering: If I cut back ill I lose out on protein? No, says Dr. Giampapa. We can get the protein we need from food without consuming meat at all.

A wide array of plant foods, including beans and grains, are excellent sources of protein, says Dr. Lieberman. Some, such as soy and the grain quinoa (pronounced "KEEN wah"), are considered "complete" proteins because they contain all of the nine essential amino acids we need to stay healthy. But our bodies will make their own complete proteins if we eat enough calories and a variety of plant foods, such as nuts and seeds, grains, and fruits and vegetables.