Protein Requirements Change With Age — Here Is the Evidence

Anabolic resistance

As adults age, skeletal muscle becomes less responsive to the anabolic signals of protein and resistance exercise. This phenomenon, called anabolic resistance, means that older adults need a higher per-meal protein dose to trigger muscle protein synthesis than younger adults.

While the RDA for protein is 0.8 g/kg body weight per day, many geriatrics and sports nutrition researchers suggest that older adults benefit from closer to 1.0–1.2 g/kg, with higher targets during illness, injury, or active resistance training.

The leucine threshold

Leucine is the key amino acid that flips the muscle-building switch. Research suggests that a meal containing roughly 2.5–3 g of leucine is needed to maximally stimulate muscle protein synthesis in older adults. This typically corresponds to 25–40 g of high-quality protein per meal, depending on the source.

Animal proteins such as eggs, dairy, fish, poultry, and lean meat are leucine-rich and highly bioavailable. Plant proteins can meet the threshold too, but usually require larger portions or strategic combinations to deliver the same leucine dose.

Distribution matters

Spreading protein evenly across meals appears more effective for muscle maintenance than eating most of it at dinner. Aiming for 25–40 g at breakfast, lunch, and dinner — plus resistance exercise — supports strength and functional capacity better than the same total protein eaten in one or two large doses.

Protein timing around exercise adds a modest benefit. Consuming 20–40 g of protein within a few hours of resistance training can enhance the muscle-building response, especially in older adults.

Anabolic resistance

The leucine threshold

Distribution matters

References