Where Do You Get Your Protein On A Plant Based Diet?

Written by: Sydney Jones, Florida State University Dietetic Intern
Edited by: Meredith Parmley, MS, RD, CSSD, LD Memorial Hermann Sports Medicine Institute

Plant-Based Diets

Plant-based diets have become increasingly popular for the general public and athletic/active populations. Social media has put a spotlight on plant-based diets, with some professional athletes starting to publicize their vegan or vegetarian diets [5].

This begs the question: what is a plant-based diet? Being plant-based means eating a diet focused on foods primarily from plants, including fruits, vegetables, nuts, seeds, whole grains, and legumes. There are many types of plant-based diets depending on the restrictions a person chooses to abide by [6]. 

There are many reasons why people choose to eat a plant-based diet, ranging from health benefits and religious practices to ethical/moral causes and animals’ rights. In addition to health benefits, a plant-based diet may provide performance-enhancing effects for various types of exercise due to high carbohydrate content and the high concentration of vitamins and minerals found in a plant-based diet [1]. 

Plant-Based Protein Considerations

Plant based diets offer an alternative source of protein to meat, dairy, and eggs. Protein intake is essential for athletes because it aids in recovery after exercise and the growth of muscle tissue.

Essential Amino Acids

Muscle protein synthesis is the process of building new muscle leading to increased muscle mass and strength [6]. There are twenty amino acids which are the building blocks of protein. Nine of those amino acids cannot be made by the body, yet are necessary to stimulate the creation of muscle proteins [7]. These nine amino acids are called essential amino acids. “Complete” proteins contain all nine EAAs, and higher amounts of EAA indicate a higher quality protein source[6]. Leucine is an EAA that stands out from the rest, as leucine alone can stimulate the muscle building process [3]. High-quality protein usually includes meat, dairy, and eggs which are all leucine rich. 

The risk of plant based diets are that plant sources of protein typically contain lower levels of EAA and are poor sources of leucine. Most plant based proteins do not contain all nine essential amino acids with the exception of soy, quinoa, and nutritional yeast. Despite popular opinion, it is possible to achieve adequate amounts of EAA through plant-based sources for muscle development by planning meals to include multiple sources of plant based protein [3]. 

In people resistance training twice a week while consuming a daily protein intake of 1.6g/kg body weight, muscle mass and strength gains were similar regardless of whether they were following a plant-based diet and supplemented by soy protein or an omnivorous diet supplemented by whey protein. Therefore, it seems the stimulus from resistance training and total daily intake of protein from high quality sources like whey or soy are the most impactful predictors of muscle building [11]. By incorporating more soy-based products into the diet, using plant based protein powders/bars, and combining multiple sources of plant based protein, those following plant-based diets can consume all nine EAA at each meal or throughout the day.

Protein Intake

The general recommendation for protein for athletes or active individuals is 20-40g per serving [6]. For older adults, it is recommended to consume 40g of protein per serving to optimize MPS. Active people should consume about 1.4g-2.0g of protein per kg of body weight each day [6]. Because plant based proteins are lower quality and can be more difficult to digest, plant-based athletes should focus on the higher end of protein intake of 1.7g-2.0g/kg to overcome these limitations [5]. An 160lb vegan athlete is 72.7kg(160/2.2), so they would need 123-145g of protein per day of trying to meet the goal of 1.7-2.0g/kg.

Digestibility

Unprocessed plant proteins are typically more difficult to digest than animal protein because the structures and composition of plant proteins are more resistant to being processed by the digestive system. High amounts of fiber and some nutrients can limit the ability of enzymes to break down plant protein into the individual amino acids needed to build muscle. Heating cooking plant proteins through the cooking process is one way to improve their digestibility. Plant protein isolates or concentrates such as soy/pea protein powders and vegan meat substitutes can also be helpful tools which are easier to digest and will help meet an individual’s daily protein needs, especially on-the-go.

Volume

Because plant proteins are lower quality than animal proteins, one would need to eat significantly larger portions of plant sources to absorb and utilize the same amount of protein. The larger volume of food and the increased fiber consumption can lead to athletes experiencing fullness too quickly, which can result in insufficient daily calories and/or protein. To overcome this challenge, one can consume foods that are lower in volume and high in protein whenever possible. Nutritional yeast, edamame, tofu, and hemp or pumpkin seeds are great ways to eat more protein without having to eat a large amount of food at one sitting. Liquid sources of protein such as soy milk or protein-enriched non-dairy milks and yogurts can also be used to increase protein without increasing volume. 

Where to Get Protein on a PBD?

The best plant-based protein sources include beans/legumes, nuts/seeds, certain vegetables and grains, and soy products such as tempeh and tofu. The amount of new plant-based protein products on the market makes it significantly easier to achieve adequate daily protein intake for athletes and active individuals.

In a recent study, researchers compared active people on a PBD using meat substitutes or a PBD using whole foods to an omnivore diet [12]. They found that after eating similar amounts of protein daily all three groups had similar gains in strength [12]. The main takeaway is to meet daily protein goals whether using only whole foods or incorporating meat substitutes though supplementation and vegan meats may make it easier to consume enough protein. 

Complementary pairings help meet daily protein targets since they are combinations of different plant-based protein sources that together contain all nine essential amino acids. Although it’s best to consume complementary protein pairings at each meal, if this isn’t feasible it is recommended to eat a variety of plant protein sources every few hours [13].

Example plant based protein combinations:

-    Beans and Rice 
-    Almond butter and oatmeal
-    Hummus and whole wheat bread
-    Soy milk with whole grain cereal

Legumes + Whole grains, nuts, or seeds= Complete Protein [9]

Conclusion:

The best way to build muscle is through resistance exercise and frequently eating protein. Including complementary protein foods and supplements after working out and before going to bed can also aid in recovery and muscle growth/strength. 

5 Ways to Increase Protein Intake on a Plant Based Diet:

1.    Take the time to plan out meals and be aware of what foods contain protein. 
2.    Include more soy-based products or vegan meat alternatives to meals as an easy way to increase protein.
3.    Try to combine multiple protein sources at each meal and snack when possible.  
4.    Use plant based protein powders (containing at least 20g protein), protein bars, and other plant based protein supplments regularly.
5.    Add nutritional yeast, hemp/pumpkin seeds, and protein enriched non-dairy milk and yogurt to meals and snacks. 

Have questions? Please feel free to talk to an Athlete Training and Health Performance Coach or Meredith Parmley, MS, RD, CSSD, LD, Sports Dietitian with the Memorial Hermann Rockets Sports Medicine Institute. Meredith can be reached at Meredith.Parmley@memorialhermann.org or can be found on Instagram at @meredithdarcienutrition. 

References 

1. Benefits of a plant-based diet and considerations for the athlete | European Journal of Applied Physiology
2. Muscle protein synthesis in response to nutrition and exercise - PMC.
3. Plant-based food patterns to stimulate muscle protein synthesis and support muscle mass in humans: a narrative review
4. Making Sense of Muscle Protein Synthesis: A Focus on Muscle Growth During Resistance Training in.
5. Vegan Diets - Practical advice for athletes and exercisers.pdf
6. International Society of Sports Nutrition Position Stand: protein and exercise
7. Protein Consumption and Resistance Exercise: Maximizing Anabolic Potential
8. Complementary Plant Proteins
9. THE PROTEIN-SPARING ACTION OF CARBOHYDRATES | JAMA
10. International society of sports nutrition position stand: essential amino acid supplementation on skeletal muscle and Performance
11. High-Protein Plant-Based Diet Versus a Protein-Matched Omnivorous Diet to Support Resistance Training Adaptations: A Comparison Between Habitual Vegans and Omnivores | Sports Medicine
12. SWAP-MEAT Athlete (study with appetizing plant-food, meat eating alternatives trial) – investigating the impact of three different diets on recreational athletic performance: a randomized crossover trial | Nutrition Journal.
13. Plant Proteins: Assessing Their Nutritional Quality and Effects on Health and Physical Function - PMC