In overweight and obese women aged 60–75, a higher protein diet (1.28 g/kg/day) during resistance training does not significantly enhance improvements in muscular strength, endurance, or aerobic capacity beyond those achieved with resistance training alone or with a higher-carbohydrate diet.

When older adults perform resistance exercises, their muscles experience mechanical tension that triggers signals inside muscle cells to build more contractile proteins and improve how nerves communicate with muscles. This makes muscles stronger and able to work longer, regardless of whether they eat more protein or more carbohydrates. The body adapts to the physical stress of lifting weights by recruiting more muscle fibers and firing them more efficiently, and these changes happen even when protein intake is not increased beyond normal levels.