The Impact of Protein Intake on Muscle Strength in Older Adults

Adding whey protein to the diet does not improve muscle strength in older adults who already meet standard protein recommendations, according to a study from Tufts University published in the American Journal of Clinical Nutrition. The research indicates that exercise is a more effective method for maintaining and building muscle strength as people age.

The study, detailed in a May 8, 2026, report from Tufts University, challenges the common marketing claim that increasing protein intake alone leads to greater muscle mass and strength. While many food manufacturers now add protein to items like cereal, pasta, and chips to tout these benefits, the findings suggest this approach may not be effective for older populations.

Lead author and endocrinologist Lisa Ceglia, an associate professor at Tufts University School of Medicine and a postdoctoral fellow at the Jean Mayer USDA Human Nutrition Center on Research Center on Aging (HNRCA), stated that protein alone doesn’t equate to muscle strength. Ceglia worked on the study alongside colleagues including HNRCA Senior Scientist and School of Medicine Professor Bess Dawson-Hughes.

Does whey protein increase muscle strength in older adults?

For older adults who already consume the normal recommended amount of protein in their diets, adding extra whey protein does not result in increased muscle strength. Most older people in the U.S. already meet these baseline protein requirements.

The research suggests that for this demographic, protein-boosted supplements or foods do not provide the strength gains often advertised. Instead, those looking to keep their muscles youthful are better off hitting the gym.

Why does muscle strength decline with age?

The slow decline of muscle strength typically begins around age 40. This process is linked to the kidneys’ decreasing ability to effectively excrete acid from the body.

According to the Tufts University research, when the kidneys cannot remove acid efficiently, the body begins breaking down muscle. This breakdown releases basic substances that act to neutralize the acid in a manner similar to how baking soda neutralizes vinegar.

What is more effective than protein supplements for muscle maintenance?

Exercise is a better bet than protein powder for building muscle strength in older adults. While protein is a necessary component of a healthy diet, it cannot replace the physiological stimulus provided by physical activity.

The decline in strength can lead to severe consequences for older adults, including an increased risk of falling or the loss of the ability to live independently. Because protein supplements alone did not change muscle strength in the study, the researchers emphasize the importance of active exercise to mitigate these risks.