According to the USDA, the key to a healthy vegetarian diet is variety. In the past, some nutritionists advised a concept called complementary proteins. According to this concept, a vegetarian needs to combine different protein sources in the same meal (pairing rice with beans, for example) depending on the foods' amino acid makeup. This concept created many a headache for vegetarians -- figuring out which food contained leucine and which had the requisite lysine required a chart and some calculations. Today, nutritionists and government agencies say that it's important to vary sources of protein, but it isn't necessary to do so in the same meal.
Vegetarians on the market for non-animal protein have a huge variety of choices. Legumes like lentils and peas, whole grains, and seeds and nuts are all good sources of protein. Soy protein is just as complete as animal protein. Tofu, made from coagulated soy milk, is extremely high in protein and available in a variety of forms and flavors. TVP (textured vegetable protein) is a dried soy flour product that can be used as a meat substitute. Most “mock” meats are made from seitan, or wheat gluten, which is known for its versatility in recipes. It’s good to stick to low-fat protein sources instead of trying to replace meat with something high in fat, like cheese. A varied diet is important for everyone, not just vegetarians or vegans.
According to the American Heart Association, most Americans exceed their protein requirement [source: American Heart Association]. Meat is high in protein, but can also be in high in fats, especially saturated fat. Eating too much meat can actually lead to coronary heart disease and other diseases, like diabetes. Diets high in protein can also lead to kidney problems. Following a high-protein fad diet that eliminates or severely reduces carbohydrate intake can also leach calcium from the bones. Vegetarian or not, everyone should eat a balanced diet.
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