Myth or fact: you can never eat too much protein for muscle

• Protein boosts the effect of strength training but does not replace it.
• Muscle benefits plateau at about 1.6 g/kg (0.7 g/lb) a day.
• Most Americans get enough protein from food without shakes.
• Protein matters especially for older adults, together with strength training.

Myth: the more protein, the more muscle

“Proteinmaxxing” trends suggest adding protein to everything (coffee, ice cream, cereal) and eating as much as possible.

Fact: there is a ceiling

A meta-analysis of 49 randomized trials with more than 1,800 participants found that extra protein increased gains in muscle mass and strength during resistance training. But the effect was modest, and above about 1.6 g of protein per kg of body weight a day there was no further benefit. The effect was smaller in older and less-trained people (Morton et al., 2018).

For a 170-lb (77-kg) person, that ceiling is about 125 g of protein a day.

What it means

• The key is regular strength training, at least 2 days a week.
• Spread protein over several meals during the day.
• Choose varied sources, including plants: beans, tofu, nuts.
• Extra protein beyond your needs is just extra calories.