Building or maintaining muscle mass is important for improving physical fitness, enhancing quality of life and promoting a healthy body weight. For sure, this is essential for athletes, but building muscle also is important for the rest of us, especially as we get older.
A key step in building muscle is eating enough protein. If you pay attention to the claims of supplement marketers or people touting the new “perfect” diet, you might think that protein is the only thing that matters. Unfortunately, that’s not the case. To really build muscle requires resistance exercise. You may need extra protein, too, but it’s the exercise that promotes the muscle growth.
There are good reasons to think that protein is important for developing muscle. First, muscle is made of protein, so you do need dietary protein to build muscle protein. Second, there are many studies that show that giving people who are doing resistance training extra protein does enhance muscle mass and strength. This is used as “evidence” that protein supplements are necessary, when it may really be the weight training that is improving strength.
One study looked at the effect of increasing protein intake on muscle mass in people who were not doing any resistance training. These were older men who could benefit from both extra protein and increased muscle mass. The results showed that the extra dietary protein did not increase muscle mass. Since the subjects were not doing any muscle building exercise, this suggests that resistance training is needed to promote muscle development.
Lifting weights or doing other resistance exercise builds both muscle mass and strength. The primary adaptation that results in increased muscle is hypertrophy, a process in which the muscles literally get larger. Resistance training causes a series of changes within the muscle that repair damage and stimulate protein synthesis. This why having adequate protein in the diet is important; you must have the protein available for the muscle to use it.
This only works if the muscle needs the protein, and that demand comes from doing resistance exercise. Having extra protein without exercise to stimulate the muscle wouldn’t have much effect on either muscle size or strength. But when someone is doing strength training, having enough protein at the right time is critical to maximizing strength gains.
The RDA, the minimum amount that meets the needs of most healthy adults, is 0.8 grams of protein per kilogram of body weight (g/kg) per day. You can calculate your protein requirement by multiplying your body weight in pounds by 0.4, so a 200 lb. person would require about 80 g protein per day. While the RDA is a minimum, many people may benefit from more, and it is certainly too low for athletes engaged in strenuous endurance or strength training. One study suggests that 1.6 g/kg per day, about twice the RDA, is a good goal for people who are trying to build or maintain muscle mass through resistance training.
You should get your protein from food, not supplements, to meet both energy needs to fuel your exercise sessions and provide adequate protein for muscle repair and growth. Timing matters, too: Protein intake immediately after exercise is particularly effective, so follow a workout with a protein rich meal or snack.
Even if you aren’t actively training to build muscle, the combination of regular resistance exercise and adequate protein intake is essential to maintain muscle mass and strength as well as helping you maintain your weight.