Do Protein Supplements Work for untrained people?
This site published the summary points of a 2016 review paper on whether protein supplements actually work, which can be found in the nutrition resources section of this website. To provide further information for readers, we summarize here another review paper published in 2015 by different authors addressing the current research on protein supplements for untrained individuals. The information is summarized below with some of our comments (CFEMC). A link to the full-text follows at the end.
Protein vs a placebo providing no energy
Some studies such as Antonio et al and Eskine et al found no effect of protein supplementation on muscle mass and strength after 6 weeks of combined aerobic and resistance training and 12 weeks of training on the elbow flexors, respectively. However, Fern et al found that 2 g/kg of protein powder daily enhanced muscle mass but no measure of strength was recorded. Hulmi et al found enhanced muscle hypertrophy when whey protein was consumed immediately before and after a bi-weekly, 21 week resistance training program. However, this did not translate into consistent gains in strength. The authors concluded: "As such, the effect of protein supplementation when compared with non-energy providing placebo on resistance training-induced gains in muscle and strength in untrained adults remains unclear" (p. 113)
Protein vs Carbohydrate
Coburn et al demonstrated greater gains in skeletal muscle strength and cross-sectional area for those consuming leucine/whey protein supplements vs energy-matched carbohydrate supplement during an 8 week (3 days/week) resistance training program. Willoughby et al found that a supplement containing: whey, milk, casein and free amino acids taken 1 hr before and immediately after an exercise session increased muscle strength greater vs a carbohydrate supplement. Lean and total body mass increased in both groups.
Weisgarber et al found no difference between a post-workout protein supplement and an iso-caloric carbohydrate supplement on measures of strength, and neither group had gains in lean mass. However, the issue with this study was that over the course of 8 weeks, the total caloric intake, as well as protein and carbohydrate consumption decreased in both groups. This may have compromised the results of the study.
CFEMC comment: It seems likely that according to the data presented in this specific paper, a protein supplement may be superior at increasing muscle strength and mass compared to a carbohydrate supplement. But more research is needed.
Type of Protein vs Carbohydrate
Candow et al compared soy, whey and carbohydrate supplementation. Lean mass and strength increased more significantly in the protein groups vs the carbohydrate group. However, surprisingly there seemed to be no significant different between whey and soy. The authors point out that this may be due to the already high daily protein intakes of the subjects.
Volek et al. also compared whey, soy and carbohydrates during a 9-month resistance training program in which supplements were given right after exercise sessions AND in the morning on non-training days. Whey protein increased lean mass more vs soy or carbohydrates but no differences were found in 1 repetition maximum for bench press or leg press.
Herda et al. compared 4 study groups: whey protein, a modified whey protein (to change absorption), isocaloric carbohydrate, and non-supplement control group. All supplements were given immediately before and after sessions plus one supplement dose in the morning on non-training days. Gains in lean mass, cross sectional area, and bench press and leg press strength + endurance were equal for all groups.
CFEMC comment: It could be possible that the type of protein (whey or soy) doesn't matter if the daily overall intake of protein is high. It is surprising also that the authors' report in this section may suggest that protein supplementation may not be as beneficial as often is thought because even carbohydrate groups and controls had similar results to the supplement groups in the Herda et al study. The results reported in the review highlight need for more research.
Combining Protein and Carbohydrate
Bird et al. compared carbohydrate + essential amino acids (EAA) vs EAA vs carbohydrates vs placebo provided throughout training sessions. Muscle isokinetic leg strength, lean muscle mass, and mean fiber type 1 and 2 cross sectional area (CSA) increased in all groups. Gains inmuscle mass and CSA were higher fro the EAA + Carbohydrate group. However, this did not translate to greater strength. Vieillevoye et al did not find differences in changes of lean mass and maximal isokinetic force during bench press and leg squat exercise when comparing an EAA + carbohydrate group to a carbohydrate-only group. However, participants seemed to average 1.3 g/kg of protein intake initially. The authors posit that this intake may have been adequate without the need of additional supplementation. Olsen et al found similar results as Vieillevoye.
CFEMC comment: Combining proteins and carbohydrates in a supplement may be beneficial. But the results reported in this review are mixed.
Milk and Dairy as supplements
Walberg-Rankin et al didn't find significant differences in adaptations to a 10-week resistance training program when comparing a low fat ilk supplement with a carbohydrate supplement. Hartman et al found that fat free milk increased strength and muscle mass, type 2 fiber CSA greater than soy protein or carbohydrate. Women consuming a milk supplement during a 12-week training program had greater increases in lean mass and decreases in fat mass vs women receiving carbohydrate (Josse et al). A 1-serving sized yogurt supplement containing 5g of protein provided immediately post-workout for 8 weeks of training did not differ fromwhey or carbohydrate supplement groups in terms of lean mass and strength improvements.
Some conclusions by the Reviewers
"Protein supplementation likely has no effect on lean mass and strength when training programs last 8 weeks or less .... However, substantially increasing the frequency or duration of exercise, or manipulating both in combination with protein supplementation does appear to enhance gains in muscle mass and measures of muscle strength in untrained individuals... Assuming the training program is of sufficient intensity, frequency, and duration, and dietary protein intake is more than adequate for physically active adults, protein supplementation may enhance gains in muscle mass, strength, and myofibrillar protein synthesis regardless of protein source (eg., whey, soy, and milk)." (p. 117)
Conclusions by CFEMC
Clearly the data is not as clear cut as we may like or as some may suggest, however the tendency seems to be towards showing that protein supplements may be beneficial when compared with carbohydrate, but whether it is beneficial when protein intake is adequate is not clear. We recommend that individuals eat a protein adequate diet and then consider possibly experimenting with protein supplements.
Pasiakos, SM., McLellan T., Lieberman, H. The effects of protein supplements on muscle mass, strength, and aerobic and anaerobic power in healthy adults: A systematic review. Sports Med (2015) 45:111-131