Protein and muscle in older adults: what the evidence supports

Muscle is built and maintained through a constant balance of protein synthesis and breakdown. In older adults, muscle becomes somewhat less responsive to the signals that trigger building — a phenomenon researchers call anabolic resistance. Practically, this means an older adult may need a stronger stimulus to get the same muscle-building response a younger person gets easily.

Two levers that matter

The first lever is dietary protein. Many older adults eat less protein than would best support muscle maintenance, partly because appetite and intake tend to decline with age. Nutrition researchers, including those at McMaster University's exercise metabolism group, have explored how distributing adequate protein across meals can better support muscle in older adults than concentrating it in a single meal.

The second lever — and the more powerful one — is exercise. Resistance training sharply increases muscle's sensitivity to protein for a period after each session. In other words, training and nutrition are not competing strategies; they are partners. The protein you eat does far more for your muscle when it lands on a body that has been training.

A note on supplements

Protein powders and amino-acid supplements are convenient but not magic. Whole-food protein sources work well for most people, and no supplement substitutes for the training stimulus itself. Anyone with kidney disease or other medical conditions should review protein intake with their physician or a registered dietitian before making changes. This summary is educational and is not individual medical or nutrition advice.