Building muscle? Here’s how to get the protein you need without meat

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Q: I’m a vegetarian who trains three times a week to gain muscle. Can I get enough protein without eating meat, chicken or fish?

Short answer: You don’t need to eat meat, or any other animal protein for that matter, to help build muscle from resistance exercise.

That’s providing, though, you consume enough protein each day from a variety of plant sources.

There’s one more caveat. To maximize muscle growth, research suggests you need to distribute your protein evenly across your meals.

Here’s a protein primer – how much you need for everyday health, the extra that’s required for adding muscle, plus how to get enough from a meatless diet.

Vegetarian eating patterns

Vegetarian diets range from those that avoid all animal foods to others that include only a few.

Vegan diets exclude all animal products – meat, poultry, fish, eggs and dairy.

Lacto-vegetarian diets includes dairy, but omit meat, poultry, fish and eggs. Lacto-ovo vegetarians eat dairy and eggs, but avoid meat, poultry and fish.

Flexitarians eat a mostly plant-based diet but occasionally consume animal foods.

Protein quality: animal versus plant

When it comes to synthesizing proteins, be it muscle tissue or other, your body relies on a steady influx of amino acids, the building blocks of proteins.

Animal foods supply all nine essential amino acids in sufficient quantities. As such, they’re considered “complete” protein sources.

Plant proteins (e.g., pulses, nuts, seeds, whole grains), on the other hand, are low in or lacking at least one or more essential amino acids. The amino acid profile of soybeans is close to that of animal protein.

One essential amino acid, leucine, acts as a trigger for muscle protein synthesis when consumed in adequate amounts. Plant proteins generally have a lower leucine content than animal proteins.

Due to the fibre in whole plant foods, plant protein is not as readily absorbed by the body as animal protein.

It’s necessary to include an adequate amount of protein at each meal to activate muscle protein synthesis. Research suggests it takes 20 to 30 g of protein a meal to do so.

How much protein?

For sedentary people, the recommended dietary allowance (RDA) for protein is 0.8 g per kg of body weight a day.

The RDA protein target is too low, however, if your goal is to build muscle or hold on to it when you’re older.

To preserve muscle, older adults need more protein each day, 1.2 g protein/kg body weight. With age it takes a greater amount of protein to stimulate protein synthesis than when younger.

To gain muscle you need even more.

According to a 2022 review of 74 randomized controlled trials, a daily protein intake of at least 1.6 g protein/kg body weight is needed to increase lean body mass during strength training in adults under age 65. (Physical activity is the most potent stimulus for protein synthesis.)

Among adults 65 and older, consuming 1.2 to 1.6 g of protein per kg each day led to a small gain in lean body weight with resistance training.

Consuming twice as much protein as the official RDA led to a gain in lean body mass of 2.9 to 3.1 pounds among 66 studies in the review.

Can a vegetarian build muscle with these higher protein targets?

According to Stuart Phillips, a professor in kinesiology at McMaster University and a Tier 1 Canada Research Chair in Skeletal Muscle Health and Aging, “with a judiciously planned diet – I emphasize this – there’s no reason why a vegetarian can’t do fine on 1.6 g of protein per kg … a vegan would, based on all evidence, also be fine.”

Translating protein goals into meatless meals

For a 170 lb. (77 kg) person, 1.6 g protein/kg body weight/day equates to 124 g of protein.

To ensure protein synthesis is sustained throughout the day, you’ll need to divide that protein evenly across three or four meals. Three meals, each containing 41 to 42 g of protein, will get you to that daily protein goal of 124 g.

For plant-based eaters, you’ll get 41 g of protein from 2 cups of cooked chickpea pasta (27 g protein) plus three-quarters of a cup of shelled edamame (15 g). Or 170 g of extra firm tofu (28 g), 1.5 cups of cooked quinoa (12 g) served alongside a tablespoon of hemp seeds (3 g) delivers 43 g of protein.

If you eat dairy and eggs, you’ll find 24 g of protein in one cup of Greek yogurt, 28 g in one cup of cottage cheese, 12.5 g in two large eggs and 8 g in one cup of milk (ditto for soy milk).

Protein powders can be used to supplement your protein intake. Whey protein isolate (made from dairy) provides 25 g of protein a serving; plant-based protein powders typically deliver 20 g.

Leslie Beck, a Toronto-based private practice dietitian, is director of food and nutrition at Medcan. Follow her on Twitter @LeslieBeckRD