How do vegetarians get enough protein?

Vegetarians eat lots of leafy greens -- but where's the protein? See more pictures of vegetables.
Andrey Popov | Dreamstime

You may have heard of the Atkins diet, a high-protein diet that started a trend and threw nutritionists and the media into something of a protein obsession. Is protein really that important? And what about vegetarians? If you're not eating meat, are you missing something important in your diet?

Proteins help make up all cells in the human body, from your hair to your blood transport molecules. A person deficient in protein can't grow, loses muscle mass and has weakened immune, heart and respiratory systems.

Proteins are organic compounds made of amino acids. The body can make some of its own amino acids -- these are called nonessential amino acids. The amino acids the body can't make on its own are called essential amino acids. People have to get these proteins from the food they eat.

If a food contains enough essential amino acids, it's called a complete protein. Meat, fish, shellfish, eggs, milk and soy products are complete proteins. If the protein in a food doesn't have all the essential acids, it's an incomplete protein. Fruits, grains and vegetables are incomplete proteins.

There are different kinds of vegetarian diets. Vegans are the strictest kind of vegetarian -- they eat only plant products. Lacto-vegetarians allow dairy products, and lacto-ovo-vegetarians allow eggs as well as dairy products. People who abstain from red meat but who still may eat chicken or fish are called semi-vegetarians or partial vegetarians.