What is The Optimal Protein Intake for Muscle Growth?
Dietary Protein is Absolutely Essential For Muscle Growth
It has been widely accepted that alongside resistance training, dietary protein is absolutely essential for muscle growth. Only if your protein intake is sufficient to meet the demand of your muscles as they are broken down through exercise (also known as the catabolic state), can new muscle be formed. Furthermore, even if you’re not exercising, a minimum amount of protein must be consumed if you want to keep the muscle you do have. In short, no protein = no gains—no matter how many hours you’re putting in at the gym. So, now that you know that protein is essential for keeping and building muscle, you may be wondering: is there a most optimal amount of protein for maximum muscle growth? This is an integral question and one that has stymied scientists and nutrition and exercise experts for decades. My objective in this article is to analyze the available research to provide some satisfactory answer to this controversial point.
Can you have too much of a good thing?
If you’re tapped into current fitness and nutrition culture, you might be familiar with the “protein ceiling”, also known as “the muscle full effect”, which suggests that there is a limit to the amount of dietary protein that you can consume before your muscles are physically incapable of using it to synthesize new muscle. Some studies have argued that protein in excess of this limit is oxidized and turned into urea in the body and thus rendered pretty much useless.
The equation commonly used in the worlds of fitness and nutrition to determine one’s ideal protein intake is based largely on one’s body weight–with some wiggle room to account for an individual’s activity level. 0.8 grams of protein for every kilogram of body weight has been generally accepted as sufficient for most sedentary people to prevent protein deficiency. The American College of Sports Medicine suggests that physically active individuals, especially those that perform resistance training, are to consume between 1.2 – 1.7 grams/kg of body weight.
There has also been some debate as to the potential deleterious effects on the body of eating too much protein. Some sources have claimed that excessive protein consumption can wreak havoc on your liver, kidneys and bones, and perhaps even leading to osteoporosis.
Not so fast…
Some new research has found that there exists no practicable upper limit for protein consumption, and that the central assumption that one’s protein needs can be calculated in relationship with one’s body weight is flawed and demands interrogation. But if we can’t calculate our protein needs by how much we weigh, what measure should we use? Some studies make a convincing case that we should be looking at a multitude of factors, including, but not limited to: gender, age, carbohydrate availability, the type of protein, and the type and intensity of exercise.
More muscles worked = more protein needed
One recent study suggests that it is the type of exercise that is the greatest determinant of our protein needs. In this study, resistance-trained men of differing weights and lean body mass were divided into two groups: those with lower weights and lower lean body mass, and those of a higher weight and lean body mass. Both groups were led through the same two full-body exercise sessions. Post-workout, some of the men were randomly assigned a 20g whey protein meal, and the others a 40g whey protein meal. They found that, no matter the size of the man and his lean body mass, muscle protein synthesis was about 20% higher in the 40g group than in the 20g. The study’s authors suggest that “the most likely explanation for the difference in response of MPS to resistance exercise and protein ingestion is the amount of muscle activated during the exercise bout”. Most studies, for whatever reason, use only lower body exercises in their study, while this study’s participants performed full-body workouts. The authors speculate that with everything else being equal, the more muscles you use in your workout, the greater your post-workout protein needs. Granted, these results may differ depending on the timing of the protein, the protein type, the sex and the age of the participants, etc–all of which warrant closer scientific analysis.
And what of the claim that too much protein is bad for your health?
When it comes to your kidneys, most experts agree: a high protein diet will not adversely affect your renal function–unless your kidney health is already poor. Many studies have shown that though a high protein intake may damage an already-diseased or dysfunctional kidney, protein will not cause renal damage.
And what of the claim that a high protein diet will increase your risk of developing osteoporosis? One large study analyzing the bone mineral density of 391 elderly women and 224 elderly men over a period of four years found that, even after adjusting for age, weight, height, weight change, total energy intake, smoking, alcohol intake, caffeine, physical activity, and calcium intake, those participants in the lowest percentile of protein intake demonstrated marked bone loss in comparison to those with a moderate to high protein intake. So, as the authors concluded, the risk of developing osteoporosis may be higher with a protein-restricted diet.
So, how much protein should you be eating? This may seem like a cop-out, but everyone’s bodies and goals are different. If your objective is muscle growth and you are following a resistance-training protocol, your protein intake should be higher. Plus, a minimum amount of protein needs to be consumed every day if you want to maintain the muscle that you already possess (and you probably should maintain it). A recommendation that seems to be universal is to make sure you’re getting all of your food–not just your protein–from a variety of sources. I hope this helps!
Wishing you all the best on your journey to optimum health!
Written by Theresa Faulder, Master’s in English, Certified Personal Trainer and Infofit fitness blog writer.
Certified Sports Performance and Fitness Nutrition Specialist$2,094.75 – $3,144.75