Muscle protein synthesis remains the same regardless of protein source, timing, or moderate intake when sufficient.
- Muscle protein synthesis is unaffected by plant or animal protein sources
- Even protein distribution across meals does not enhance muscle gain
- Moderate protein intake is just as effective for building muscle
Muscle growth occurs at the same rate whether protein comes from plant or animal sources, as long as the intake is sufficient and balanced. Distributing protein evenly throughout the day and consuming moderate yet adequate amounts also showed no significant impact on muscle-building response (1✔ ✔Trusted Source
Impact of Vegan Diets on Resistance Exercise-Mediated Myofibrillar Protein Synthesis in Healthy Young Males and Females: A Randomized Controlled Trial
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).
These findings challenge long-held views and were detailed in Medicine and Science in Sports and Exercise, a journal focused on sports science and exercise physiology.
A Vegan High Protein Diet focuses on plant-based protein sources like lentils, tofu, quinoa, and beans, avoiding all animal products. In contrast, an Omnivorous High Protein Diet includes both animal-based proteins like meat, eggs, and dairy, along with plant-based options, offering a wider variety of protein sources.
Longstanding Beliefs About Animal Protein Challenged
It was widely accepted that animal protein, because of its higher digestibility and amino acid profile, was more effective for muscle building. Nicholas Burd, a professor of health and kinesiology at the University of Illinois Urbana-Champaign, explained that earlier single-meal studies had shown greater muscle protein synthesis after animal-based meals compared to vegan options.
Based on these earlier results, Burd and his team hypothesized that omnivorous diets would be superior for muscle growth. However, he noted that measuring the effects after one meal does not provide a complete picture of how a varied plant-based diet might affect muscle over time.
Previous Trials Missed Real-World Eating Patterns
A prior controlled trial compared muscle-building effects between vegans and omnivores over ten weeks. While it showed no difference, participants consumed very high protein levels—between 1.6 and 1.8 grams per kilogram of body weight per day—mostly through supplements. According to Burd, this setup did not reflect how people normally eat, especially on a vegan diet.
To improve on this, Burd’s new investigation focused on whole foods rather than supplements, testing more realistic protein consumption of about 1.1 to 1.2 grams per kilogram of body weight per day. This level is more aligned with the typical American diet and still supports strength training.
Whole Food Protein Sources Used in Trial
The study included 40 healthy, physically active adults aged 20 to 40. Participants began with a seven-day standardized “habituation diet” to normalize their nutritional status. A habituation diet focuses on gradually reintroducing foods to your diet in a balanced manner, helping to reset your body’s relationship with food. It emphasizes mindful eating, ensuring your body adjusts to new habits and food patterns over time. Then, they were randomly assigned to either a vegan or omnivorous eating pattern, with all meals prepared and provided by the research team.
About 70 percent of the protein in the omnivorous group came from sources like beef, chicken, pork, eggs, and dairy. Vegan meals were carefully constructed to include a complete profile of amino acids using a diverse mix of plant-based foods to ensure protein quality.
Meal Frequency and Protein Distribution Studied
Each group was further divided based on how their daily protein was consumed. Some participants ate three meals with equal protein content, while others spread their intake across five meals with more protein later in the day.
In addition to the diet, all participants took part in supervised resistance training every three days. Their general activity outside the lab was monitored using accelerometers to ensure consistent physical movement levels.
Innovative Tracking of Protein Synthesis
To measure how the body used the consumed protein, participants drank water labeled with deuterium, a stable isotope of hydrogen. This isotope bound to amino acids in the body, allowing researchers to trace its incorporation into muscle tissue. Muscle biopsies from the leg were collected before and after the nine-day training period to track protein synthesis directly (2✔ ✔Trusted Source
Vegan and Omnivorous High Protein Diets Support Comparable Daily Myofibrillar Protein Synthesis Rates and Skeletal Muscle Hypertrophy in Young Adults
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).
Burd admitted that the results were surprising. Despite expectations that omnivorous diets and even protein distribution would be more effective, the data showed no advantage in terms of muscle protein synthesis.
Distribution and Source Do Not Matter Much
Many experts had believed a steady intake of nutrients throughout the day was optimal. Burd also thought plant-based proteins would benefit more from careful timing because of their lower digestibility and amino acid content. Instead, the results indicated that neither distribution pattern nor protein source made a difference as long as overall intake was adequate.
Now, Burd advises people to focus on consistent, high-quality protein intake after exercise rather than stressing about whether it comes from plants or animals, or how it is spaced throughout the day.
In conclusion, building muscle does not depend on whether your protein comes from plant or animal sources, nor does it rely on how that protein is spaced throughout the day. As long as your diet includes enough high-quality protein and is paired with consistent resistance training, you can achieve similar muscle gains on either a vegan or omnivorous diet.
References:
- Impact of Vegan Diets on Resistance Exercise-Mediated Myofibrillar Protein Synthesis in Healthy Young Males and Females: A Randomized Controlled Trial – (https://journals.lww.com/acsm-msse/abstract/9900/impact_of_vegan_diets_on_resistance.771.aspx)
- Vegan and Omnivorous High Protein Diets Support Comparable Daily Myofibrillar Protein Synthesis Rates and Skeletal Muscle Hypertrophy in Young Adults – (https://www.sciencedirect.com/science/article/pii/S0022316623126800)
Source-Medindia