There is a lot of debate about the definition of vegetarianism. Some people believe that vegetarians can eat fish, while others do not. Some people even think that eating small amounts of poultry can be part of a vegetarian diet.

Omega-3 essential fatty acids have a variety of health benefits, which according to the University of Maryland Medical Center, include playing a crucial role in brain function and heart health.

An omnivorous diet includes both plant and animal foods. It’s the most common diet among humans, and many other animals are omnivores as well, including many bears, birds, rodents and other small mammals. There are a wide range of omnivorous diets, so generalizations are difficult to make.

The controversial blood type diet has claimed many adherents since the 1996 publication of "Eat Right 4 Your Type: The Individualized Diet Solution to Staying Healthy, Living Longer and Achieving Your Ideal Weight."

HDL cholesterol, known as the "good" cholesterol, promotes cardiovascular health by keeping the "bad" cholesterol, known as LDL, at desirable levels. A vegetarian diet can help raise your HDL levels and also keeps your LDL levels down, since animal products are a prime source of LDL cholesterol.

Meat, poultry and seafood are among the better sources of zinc, but vegetarians can meet the recommended dietary allowance of 8 milligrams per day for women and 11 milligrams per day for men by eating a variety of beans, grains, dairy products, nuts and seeds.

About 7.3 million people in the United States follow a vegetarian diet, according to the Vegetarian Times website. Another 22.8 million follow a semi-vegetarian diet, which includes both vegetarian and non-vegetarian foods.

Your protein requirements include not only the total amount of protein, but also the quality of protein that you get. Many plant-based foods provide incomplete proteins, but you can combine certain plant-based foods to get the complete proteins you need.

The American Heart Association recommends diets high in soluble fiber if you are aiming to lower your cholesterol. Vegetarians who eat well-planned meals with high-fiber vegetables and whole grains have diets that are naturally high in fiber.

Lacto-ovo vegetarian diets avoid meat, fish, and poultry, but include eggs, dairy products and honey. A well-balanced lacto-ovo vegetarian diet is nutritionally complete and rich in vitamins, minerals and antioxidants.

If you are considering a vegetarian diet, you may be concerned about protein. Although meat products are an excellent and well-known source of protein, it is easy for a vegetarian to substitute meatless choices for red meat, poultry and seafood.

If you're looking to boost your protein intake on a vegetarian diet, keep in mind that the recommended dietary allowance for adult men is 56 grams of protein per day and 46 grams for women.