Hitting your protein goal is always a top priority, and sources often get overlooked. In an August 24 Arnold’s Pump Club newsletter, Arnold Schwarzenegger broke down whether protein sources affect muscle protein synthesis in older adults.
In the 1970s and early 80s, Arnold Schwarzenegger established himself as a seven-time Mr. Olympia champion. He mastered nutrition, resistance training, and posing, elevating the sport to new heights. Despite stepping away from the stage, the bodybuilding legend still offers a helping hand, from longevity to sustainable dieting.
Arnold Schwarzenegger On Whether Protein Source Matters for Muscle as You Age
First, Schwarzenegger took to his newsletter and addressed the myth that you must use animal protein to reach your fitness goals.
“Myth: You need animal-based protein to get the results you desire. A new trial suggests that once you’re eating enough protein, the source may matter much less than advertised.”
He emphasized that adults experienced the same rate of muscle protein synthesis (MPS) eating plant or animal proteins.
“Adults between 50 and 70 had the same rate of muscle protein synthesis whether most of their protein came from plants or animals. The difference-maker wasn’t whey or pea protein. It was lifting.”
Schwarzenegger noted that lifting affected MPS most, and cited a study showing that MPS was higher in trained legs regardless of which diet people used.
“Researchers assigned people to one of two controlled diets for 10 days. Both supplied about 1 gram of protein per kilogram of body weight each day, but one emphasized animal foods and whey, while the other leaned heavily on plant foods and pea protein.”
“Every other day, participants trained one leg with knee extensions and left the other leg alone. Muscle protein synthesis was about 12 percent higher in the trained leg, regardless of which diet people ate. The animal-based diet delivered more leucine and other essential amino acids, yet produced no measurable advantage.”
While Schwarzenegger maintains that proteins are not all equal, he explained that those differences might not affect the end goal:
“And that reinforces what we continue to see in studies. It’s not that all proteins are interchangeable or equal. In fact, we know that some animal proteins have more essential amino acids. But we’re finding out that the difference might not influence outcomes.”
“This was a small experiment, and the researchers measured the process of muscle protein synthesis, not actual muscle growth. The plant-based diet was carefully planned and supplemented with pea protein, so this isn’t evidence that any collection of plant foods will automatically get the job done.”
The seven-time Mr. Olympia adds that protein intake doesn’t have to be complicated. He recommends eating between 1.6 and 2.2 grams of protein per kilogram of body weight, and slightly less if you’re inactive.
“But this study — along with other research — suggests once again that the story about protein and muscle preservation doesn’t have to be complicated: Get enough total protein (anywhere from 1.6 to 2.2 g/kg of goal body weight if you exercise, and as low as 1.2 g/kg if you’re inactive) from whatever source you’ll eat, train consistently, and you’ll see results.”
Schwarzenegger recently busted another protein myth that stirred up the fitness community. After claims that protein made you age faster went viral, the bodybuilding star defended the macronutrient. He explained that these studies were conducted on animals, so the argument is shaky at best.
At 79, Schwarzenegger is still handing out valuable bodybuilding tips and wisdom. Overall, he believes protein sources matter far less than total intake as we get older.
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