How much protein do you actually need?

Protein is the fitness world's favourite argument. The honest answer is less dramatic than the supplement aisle suggests: there is an official number, it has a purpose, and the right number for you depends on what you are asking your body to do. This is general information, not medical or dietary advice — kidney or other health conditions change the picture, so a qualified professional is the right stop first.

The official number

The recommended dietary allowance for adults is 0.8 grams of protein per kilogram of body weight per day — about 56 g for a 70 kg adult. That figure (set in the official RDA reviews) is what prevents deficiency for most healthy adults; it is a floor, not a target for optimisation. As a share of calories, official guidance lands protein anywhere in a broad 10–35% band.

Why you will hear bigger numbers

People in serious training — and older adults, whose bodies use protein less efficiently — are commonly advised to eat more than the RDA: sports-nutrition position stands typically land in a rough 1.2–2.0 g/kg band for hard-training people, and research summaries for older adults argue for around 1.2–1.5 g/kg to protect muscle. The logic is simple: training creates the demand; protein is the raw material the overload principle spends. None of this requires precision: within those bands, consistency beats arithmetic.

Food first, powder optional

For most people, normal food covers it: eggs, dairy, beans and lentils, fish, chicken, meat, tofu, even bread and oats contribute. A rough daily picture for many adults lands within range without any powder at all. Protein powder is a convenience, not an ingredient of success — useful on heavy training days or low-appetite mornings, unnecessary as an identity. Claims that a specific shake builds muscle by itself are selling, not science.

The lines this desk will not cross

No gram targets for people with kidney or liver conditions (professional guidance first); no "more is always better" — the RDA reviews set upper boundaries for a reason; and no promising protein alone changes a body: it works inside the pair that actually does — progressive training and enough sleep (the recovery multiplier). Pair the numbers with the two-day strength habit and the arithmetic becomes background noise.

Sources

• WHO — Physical activity (fact sheet)
• CDC — Physical Activity Basics
• NIH/NCBI — Recommended Dietary Allowances: protein 0.8 g/kg for adults
• American Heart Association — Protein: what’s enough?
• UC Davis Nutrition Dept — protein requirements for health professionals