In May, researchers reported the results of a study (funded by the Australian meat industry) that enrolled 145 older adults in a supervised strength-training program three days a week.
After six months, those who were randomly assigned to eat two servings of lean red meat on each day they did strength training gained no more muscle or strength than those who ate two servings of rice, pasta, or potato instead.
“More and more evidence is showing that there isn’t a lot of benefit from extra protein, whether you’re engaged in resistance training or not,” says Bettina Mittendorfer, professor of medicine at the Washington University School of Medicine in St. Louis.
A possible exception: young adults.
“The early studies were done in young, college-aged people,” notes Mittendorfer. “If you train as much as possible and get extra protein while you’re still in that growth phase, you can see a benefit. But in middle-aged or older people, it’s very hard to find studies that show a benefit.”
And if they do, it’s usually minor.
For example, the same Australian researchers found a statistically significant effect on lean body mass in an earlier study. “But when you do the math, it comes out to about a 1 percent difference,” explains Mittendorfer. “That’s unlikely to have a clinically meaningful impact.”
And that’s the bottom line. “Even if studies find a small increase in muscle or lean body mass, most don’t find an increase in strength or physical function, which is the ultimate goal,” she says.
Why doesn’t more protein help?
“The majority of people, including healthy, free-living older adults, get enough protein,” says Mittendorfer.
On average, women get 35 percent more—and men about 65 percent more—than the Recommended Dietary Allowance (RDA), and both reach higher targets proposed by some experts.
Only 19 percent of women and 13 percent of men over age 70 get below the RDA—0.36 grams of protein for every pound you weigh. For someone who weighs about 150 pounds, that’s roughly 54 grams of protein a day, or 18 grams per meal.
“That comes down to a deck-of-cards-size piece of chicken breast at each meal,” says Mittendorfer. “It’s a small amount. We’ve become desensitized to what a normal amount of protein is.”
The information in this post first appeared in the July/August 2020 issue of Nutrition Action Healthletter.
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