People who regularly do resistance exercises may get stronger and build more lean muscle mass when they add more protein to their diet, a recent study from McMaster University in Hamilton, Ontario suggests.
Researchers examined data from 49 previously published studies with a total of 1,863 people who did muscle-building workouts like weight-lifting.
The studies included in the review looked at healthy adults performing resistance exercises at least twice a week. For each study, participants were randomly selected to stick to their usual diets or add extra protein.
No added benefit for protein intake beyond 1.6 g/kg/day
Participants who boosted their protein intake - whether from foods or from supplements like bars, powders and shakes - added more lean muscle mass and got stronger muscles than exercisers who didn’t add extra protein to their diets.
However, increasing daily protein consumption beyond more than 1.6 grams for every kilogram (2.2 pounds) of body weight didn’t appear to have any added benefit.
Performing resistance exercise is an effective way to maintain or increase lean muscle mass. And increasing protein intake is necessary to augment increases in muscle mass and strength during resistance training.
The researchers found, however, that extra protein didn’t help older adults as much as younger people.
The benefits of extra protein were also more pronounced for people new to resistance training than for those who had experience with resistance training.
Across all these studies, people adding protein to their diets consumed an extra 4 grams to 106 grams daily. Overall, the most common source of added protein was whey protein supplements, followed by supplement blends.
Ten studies gave people added protein with milk, and another seven examined adding protein with whole foods like beef and yogurt.
Results may not hold true for older adults and dieters
The researchers didn’t have enough data on older adults to determine how much added protein might help these individuals build lean muscle mass, which typically declines with age. Researchers also didn’t look at what happens when dieters get added protein.
Still, the findings offer new insight into the amount of protein some people might add to their diets to get additional benefits from muscle-building workouts.
The results might not apply to people who do resistance training less than twice a week.
Experts warn that boosting your protein intake isn’t risk-free. It can lead to digestive problems and damage the kidneys, and there’s also some concern that it may increase the risk of cardiovascular disease.
All research on this web site is the property of Leslie Beck Nutrition Consulting Inc. and is protected by copyright. Keep in mind that research on these matters continues daily and is subject to change. The information presented is not intended as a substitute for medical treatment. It is intended to provide ongoing support of your healthy lifestyle practices.