In previous clinical studies with college and pro-athletes, rice protein has been shown to be as effective as animal-based whey protein for building and maintaining muscle mass and thus improving performance. However, participants in those studies supplemented with large 48g-75g daily doses of protein, respectively. In the latest double-blind study, published in the Journal of the International Society of Sports Nutrition, subjects supplemented with a lower 24 gram daily dose of rice protein. Results of this study indicate that even this “low” or “standard” 24g dose of rice protein is as effective as whey protein for significantly improving muscle mass and athletic performance. This is the third study to date helping to support the effectiveness of plant proteins for sport nutrition use.
What are the study details?
- There were 24 healthy, resistance-trained male participants
- Participants were randomly and blindly assigned to the rice or whey protein group; 12 in each group
- Subjects completed a linearly periodized resistance training program; this means it was a routine intended to maximize strength
- Workouts were completed 4 times per week for a total of 8 weeks + 2 lead-in weeks (without protein supplementation) to get subjects acclimated to the routine; 10 weeks total
- Subjects consumed 24g rice protein (Growing Naturals brand specifically) or whey protein within 60 minutes of a workout on workout days (4x per week) as well as 24g rice or whey protein within 60 minutes of bedtime on non-workout days
- All anthropometric, body composition and performance assessments were completed at week 0, 2, and 10 weeks including:
- body mass using a digital balance
- body water using using bioelectrical impedance spectroscopy
- body composition using Dual-Energy X-Ray Absorptiometry (DEXA)
- muscular strength using one repetition maximum (1RM)
- muscular endurance using repetitions to fatigue at a load of 80% 1RM
- anaerobic power using Wingate anaerobic capacity test
- Dietary guidelines were provided regarding protein and calorie needs and participants were required to log intake at least 4 days per week via MyFitness Pal app.
What were the study results?
When looking at changes from baseline through the 8 week supplementation period, both the rice protein and whey groups experienced statistically significant increases in body mass, total body water, lean mass, fat-free mass, bench press 1RM and leg press 1RM. Additionally, there were no significant differences between the rice protein and whey protein group for any of the variables measured. In other words, whey protein was did not provide a greater benefit than rice protein and vice versa. Both proteins supported training adaptations equally.
How can plant proteins build muscle despite being “lower quality” than whey?
One of the most popular reasons cited by professionals to choose whey protein over plant based proteins is “inferior protein quality”, including a lower essential amino acid content and reduced digestibility. While it is true that plant proteins including rice protein are low in one or more essential amino acid this issue becomes irrelevant when alternate sources of protein are being consumed throughout the day. It is well-documented in the literature and by major health organizations (like CDC and AND) that complementary proteins need not be consumed in the same meal but rather within a 24 hour period. That is, the amino acids from animal- or dairy-based proteins consumed throughout the day would help your body “complete” (and use) the amino acids obtained from rice, pea or other plant proteins (in whole food or powder form).
Additionally, while the digestibility of plant proteins in whole food form such as beans and whole grains may be sub-optimal, the digestibility of processed protein powders is high due to having removed most of the starch and fiber content. This has been confirmed specifically for Growing Naturals rice and pea protein powders.
Rice Protein Benefits
The results from this study help to build the literature on plant proteins for sport nutrition use, but also further supports the effectiveness of plant protein powders like rice protein for building and maintaining muscle mass. Despite rice protein having an incomplete amino acid profile compared to whey protein, it was nonetheless able to provide equal results to those subjects consuming whey protein. For those considering plant proteins, here are the advantages of rice protein over whey or other animal-based proteins:
- Naturally free of cholesterol and saturated fat
- Free of contamination from antibiotics or growth hormones which may be used in animals
- Plant-based and thus more eco-friendly
- Leucine in rice protein gets absorbed by the body faster than leucine in whey protein. Leucine is the amino acid known for triggering muscle protein synthesis (aka muscle building).