Building Muscle on a Vegetarian Diet

Reviewed by Jill Kohn, MS, RDN, LDN
weights and fruits

What do four-time Mr. Universe Bill Pearl, triathlete Brendan Brazier and Ultimate Fighting Champion Mac Danzig have in common? Supreme muscular development for sure, but surprisingly these three top athletes follow vegetarian or vegan diets, as do a number of other top athletes around the world. For years, the conventional belief that ruled professional and amateur athletic training programs was that consuming meat was the only way to build muscle. Today, we know a balanced vegetarian diet that includes plant-based protein assists muscular development … no steak required.

Well-planned vegetarian diets that meet energy needs and contain a variety of plant-based protein foods, such as soy products, other legumes (beans and lentils), grains, nuts and seeds can provide adequate protein for athletes without the use of special foods or supplements. Consideration must be made for the type of vegetarian diet an athlete follows:

  • Vegan – a vegetarian diet that excludes all animal products, such as meat, poultry, fish, eggs, milk, cheese and other dairy products, and which relies on plant protein only to meet protein needs.
  • Lactovegetarian – a vegetarian diet that excludes meat, poultry, fish and eggs but includes dairy products, a source of protein.
  • Lacto-ovo vegetarian – a vegetarian diet that excludes meat, poultry and fish but includes eggs and dairy products, sources of protein.

Athletes need to eat small amounts of protein throughout the day to ensure this important nutrient is available when their bodies need it most. Moreover, not every source of protein is equal — it is actually the amino acids that make up protein that our bodies need. Meat, eggs and dairy foods are typically the most coveted protein sources because they contain all nine essential amino acids in the ratios that humans require. On the other hand, some plant-based proteins do not contain the essential amino acids in proportions that humans require. Include a variety of protein sources throughout the day to provide adequate amounts of all the essential amino acids, even if all of the protein sources come from plants.

Key is Protein Quality

"It's protein quality that builds muscle and there are other options than meat," says former Academy of Nutrition and Dietetics Spokesperson Roberta Anding, RD, director of sports nutrition and a clinical dietitian at Baylor College of Medicine and Texas Children's Hospital, as well as a certified specialist in sports dietetics. The standard method of determining protein quality is the protein digestibility-corrected amino acid score (PDCAAS), which compares a protein's amino acid quality based on both the amino acid requirements of humans and their ability to digest it.

Egg protein has a high PDCAAS since it contains the perfect balance of the nine essential amino acids and is easily digestible, making it an excellent protein source for vegetarians. Other vegetarian foods that have a high PDCAAS include dairy products such as low-fat yogurt and milk, and soy, including tofu, edamame, soy milk and soy yogurt.

Eat Protein at Every Meal

Anding recommends that vegetarian athletes looking to build muscle eat good quality protein at every meal. Here are some tips for building muscle without consuming meat:

  • Eat five or six small meals per day that not only include protein, but also a variety of fruits, vegetables, whole grains, nuts, vegetable oils and plenty of water.
  • More than half your calories each day should come from quality carbohydrates, which fuel your muscles.
  • Fats are necessary for supplying energy to muscles during workouts. Good sources of fat include olive oil, almonds, walnuts, avocados and canola oil.
  • Find a registered dietitian nutritionist who can work with you to create a personalized vegetarian eating plan that meets your individual needs.

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