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Extra Protein Alone Won't Build Muscle in Older Adults

aging basic-science diet-nutrition

If you're already eating enough protein, the extra scoop of whey won't move the needle. Roger Fielding's lab at Tufts ran 80 older adults through six months of resistance training, gave half of them 40 grams of whey protein daily and the other half a placebo, and both groups got stronger and built muscle at exactly the same rate. The lever that actually works is consistent exercise: aerobic activity plus one or two days a week of resistance training hitting the major muscle groups. The one protein caveat worth keeping is this: about a quarter of people aren't hitting the baseline 0.8 grams per kilogram of body weight per day, and closing that gap does matter for holding onto muscle.

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Roger Fielding, a nutrition and muscle researcher at Tufts University's Friedman School, ran the study the protein supplement industry would rather you not read. Eighty older adults did six months of resistance training; half got a daily shake with 40 grams of high-quality whey protein, half got a placebo. Both groups got stronger and gained muscle at exactly the same rate. The extra protein did nothing.

That finding comes with one real caveat. About a quarter of older adults don't hit even the baseline recommendation of 0.8 grams of protein per kilogram of body weight per day. If you're below that floor, closing the gap matters for holding on to muscle. Above it, adding more protein is not the lever.

The lever is movement. Fielding says the most effective strategy is regular aerobic activity plus one or two days of resistance training each week, working major muscle groups with free weights, machines, bands, or body-weight exercises. If you're actively losing weight, slightly more protein can help limit muscle loss alongside that training, but loading up on red and processed meat to get there trades one problem for another.

If you do want a protein supplement, Fielding recommends plain, minimally processed products. The heavily sweetened bars and shakes he describes, essentially, as junk food.

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