Does more protein actually build more muscle?

In women aged 40–77, increasing protein intake beyond standard levels did not significantly increase skeletal muscle mass, whether they did strength training alone or combined with cycling.

Test your knowledge

A woman in her 50s wants to maximize her muscle mass while also improving her heart health. Based on the study's findings, which of the following best describes how she should approach her protein intake and exercise routine?

A) She should prioritize a high-protein diet (2.2 g/kg) specifically because it is the only way to see muscle gains when adding cycling to her weightlifting.
B) She can choose her preferred protein amount (0.8, 1.6, or 2.2 g/kg) without worrying that it will significantly change her muscle mass results, regardless of whether she does weightlifting alone or combines it with cycling.
C) She must choose weightlifting alone, as the study proved that adding cycling prevents the body from building muscle even when protein intake is high.
D) She should only focus on weightlifting, because the study showed that high protein intake only works for muscle growth when you avoid aerobic exercise like cycling.

🔬 The Breakdown

Context: This highlights a common misconception: that expensive, high-protein supplements are a requirement for muscle maintenance. The data suggests that for this demographic, the specific amount of protein isn't the primary driver of muscle growth.

Reality Check: The study showed that while protein didn't change muscle mass, strength training specifically improved leg power, while cycling improved aerobic fitness. Balancing both types of exercise can be time-consuming and physically demanding.

Takeaway: Focus on consistent resistance training to build strength, and don't feel pressured to buy expensive high-protein powders to see results.

Published September 15, 2026

The science, explained

Evidence Check: This was a randomized controlled trial of 108 women (with 83 completing the full study) who were assigned to different exercise and protein groups.

Conventional Wisdom Check: This refines the common belief that 'more protein is always better' by showing that, within the tested range, extra protein didn't significantly change muscle mass outcomes for this group.

Everyday Translation: You can feel confident that hitting a moderate protein goal will support your goals without needing to obsess over the highest possible dose to see muscle results.

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