How Much Protein Do You Actually Need After 40?

The official protein recommendation for adults is 0.8 grams per kilogram of body weight per day. That figure is widely misunderstood. It was established as the amount needed to prevent deficiency in most healthy adults — a floor, not a target — and a growing body of research suggests that adults over 40 who want to preserve muscle should be aiming considerably higher.

Where 0.8g/kg comes from

Reference intakes are designed to cover the requirements of nearly everyone in a healthy population — they are public health floors intended to prevent deficiency states. They were never intended to describe the intake that best preserves muscle mass in a 55-year-old, and they are frequently quoted as though they were.

For a 70kg adult, 0.8g/kg is 56g of protein a day. Achievable, and enough to avoid deficiency. Whether it is enough to hold onto muscle through your fifties and sixties is a separate question, and the ageing literature increasingly suggests it is not.

The recommended intake answers the question ‘how little can I get away with?’. Most people over forty are asking a different question entirely.On reading nutrition reference values correctly

Anabolic resistance, and why it changes the maths

Muscle protein synthesis is the process by which the body builds muscle tissue in response to a protein-containing meal. With age, that response becomes blunted — the same dose of protein produces a smaller effect. This is anabolic resistance, and it has two practical consequences.

The first is that total daily intake needs to be higher. Expert groups working on nutrition in older adults have converged on something like 1.0 to 1.2g/kg per day for healthy older adults, rising further for those who are training or recovering from illness.

The second is that the per-meal dose matters. There appears to be a threshold — commonly put around 25 to 30g of high-quality protein — below which the muscle-building response is weak. A 70g protein dinner does not compensate for a 10g breakfast, because the body does not bank the surplus.

What that looks like on a plate

Working from 1.2g/kg, a 70kg adult is aiming at roughly 84g a day, or three meals of about 28g. Portions that get you there:

• Chicken breast, 120g — about 36g
• Salmon fillet, 130g — about 33g
• Greek yoghurt, 200g — about 20g
• Lentils, 200g cooked — about 18g
• Three large eggs — about 19g
• Tofu, 150g — about 18g
• Cottage cheese, 150g — about 18g

Plant protein needs slightly more attention

Most plant proteins are lower in leucine, the amino acid most closely linked to triggering muscle protein synthesis, and several are limited in one essential amino acid. This is straightforward to work around — combining sources across the day, or using a blended formulation designed for completeness — but it is a real consideration rather than a marketing point.

The realistic plan

Almost nobody needs to count protein forever. What helps is auditing it once, honestly, for three days, and then fixing whichever meal is furthest from target. For the overwhelming majority of people that meal is breakfast, and fixing it alone often closes most of the gap.