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Vegetarian Protein Combining


Updated June 09, 2014

Some alternative diets are vegetarian and one of the most common questions concerns protein intake on these diets. Here is a brief primer on protein and protein combining.

What is protein?

Protein is a major component of enzymes, hormones, body tissues, the immune system, and virtually every cell and fluid in the body. It is made up of building blocks called amino acids. Amino acids can be synthesized in the body, but nine of them, called essential amino acids, must be ingested from food.

How much protein do we need per day?

The recommended daily allowance (RDA) of protein is 0.8 g per kg of body weight. For example, a 130 pound sedentary adult needs 47 g of protein per day. This requirement increases with activity, and an adult who exercises regularly needs about 70 g of protein per day.

What is the difference between animal and plant protein sources?

Animal foods such as meat, dairy, eggs, poultry, and fish are complete proteins because they contain sufficient levels of all essential amino acids.

Plant proteins come from foods such as beans, nuts, peas and soy products. Milk products and eggs are good sources for lacto-ovo vegetarians.

What is a complementary protein?

Each plant has a different amino acid profile. For example, grains are low in the amino acid lysine, legumes are rich in lysine.

When the amino acids from two or more foods together make up a complete protein with sufficient levels of all the essential amino acids, these food pairings are called "complementary proteins".

Examples include grains and legumes or legumes and seeds and nuts.

People following a vegetarian diet should include a variety of foods that have complementary proteins so that the essential amino acids missing from one protein food can be supplied by another.

What are some examples of complementary proteins?

  • Beans and tortillas
  • Peanut butter sandwich
  • Macaroni and cheese
  • Tofu with rice
  • Hummus with pita bread

Chickpeas and rice

Do people following a vegetarian diet need to eat complementary proteins at every meal? It was once believed that complementary proteins had to be consumed at every meal. We now know that intentional combining at each meal isn't necessary.
As long as you eat a variety of plant foods, such as brown rice, corn, nuts, seeds, whole grains and wheat every day, your protein needs should be met.

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