Protein After 40: How Much Is Enough?

Muscle is metabolically active tissue involved in glucose utilization and the regulation of energy expenditure. Functional muscle mass contributes to better metabolic control, as well as to the activities that define independence: walking, climbing stairs, getting up from a chair, or carrying groceries.

As we age, muscle mass may gradually decline, especially in the presence of a sedentary lifestyle, insufficient food intake, or chronic illness. Importantly, we lose not only muscle mass but also strength. The European consensus on sarcopenia considers reduced muscle strength a more relevant sign than a reduction in muscle mass alone.

For this reason, muscle can be regarded as a functional reserve. The more strength we have as we enter the decades ahead, together with habits that support it, the more resources we have to get through periods of illness, immobilization, or weight loss without a significant loss of independence.

For healthy adults, the reference value commonly used is approximately 0.8–0.83 g of protein/kg body weight/day. This is a population-level reference, not necessarily the optimal intake for every person. Requirements may vary according to age, physical activity, muscle mass, energy intake, goals, and health status.

There is no recommendation stating that everyone should automatically increase their protein intake immediately after the age of 40. For older adults, however, the ESPEN guideline recommends at least 1 g/kg/day, adjusted individually, while values of 1.0–1.2 g/kg/day are frequently proposed for healthy older people.

For a person weighing 70 kg, 0.8 g/kg means approximately 56 g of protein per day, while 1.0–1.2 g/kg means 70–84 g. In people with obesity, the absolute requirement may be higher, but it does not increase proportionally with every additional kilogram because adipose tissue has lower protein requirements than muscle mass. Depending on the context, the calculation may be based on a reference weight or an adjusted weight.

More does not always mean better. A very high intake does not automatically produce more muscle mass, and recommendations may differ in chronic kidney disease. KDIGO recommends avoiding intakes above 1.3 g/kg/day in adults with chronic kidney disease who are at risk of progression.

The daily total is important, but how protein is incorporated into the diet also matters. Breakfast usually contains little protein, while most protein is consumed in the evening. A more balanced distribution across the main meals can make it easier to meet requirements and provide the muscles with more opportunities to respond to amino acid intake.

For many people, a practical reference may be to include approximately 25–30 g of protein in a main meal, without weighing every plate precisely. Such a meal may include fish, lean meat, eggs, and dairy products, or combinations of tofu, soy, legumes, and grains. Plant sources can meet protein requirements if the diet is sufficiently varied.

Protein powders and high-protein products are not essential. They may be useful when appetite is reduced, when a person’s schedule does not allow for a complete meal, or when requirements are difficult to meet through food alone. For most people, however, a well-structured, regular diet is sufficient.

Protein cannot replace exercise. Strength training signals the body to preserve and build muscle, while nutrition provides the necessary materials. The World Health Organization recommends activities that strengthen the major muscle groups on at least two days per week. Ultimately, combining movement with an adequate protein intake is more important than focusing on a specific number of grams in isolation.