How Much Protein You Actually Need
The US RDA of 0.8 g per kg is the minimum to prevent deficiency in a sedentary adult — not the amount that supports training, ageing well, or losing fat without losing muscle. Research consistently supports higher intakes for anyone active:
| Situation | Grams per kg | For an 80 kg person |
|---|---|---|
| Sedentary minimum (RDA) | 0.8–1.0 | 64–80 g |
| General fitness | 1.2–1.4 | 96–112 g |
| Maintaining muscle | 1.4–1.6 | 112–128 g |
| Building muscle | 1.6–2.2 | 128–176 g |
| Dieting while training | 1.8–2.4 | 144–192 g |
| Endurance athlete | 1.2–1.6 | 96–128 g |
The highest figures apply during aggressive fat loss, where the body is most likely to break down muscle for fuel. This is the situation where protein does the most work.
Per Meal, Not Just Per Day
Muscle protein synthesis is stimulated by a dose of roughly 25–40 g of high-quality protein, and the response saturates above that. Three or four servings of that size across the day produce a better anabolic response than the same total consumed in one sitting — though total daily intake remains the dominant factor by a wide margin.
Protein Quality
Animal proteins — meat, fish, eggs, dairy — contain all nine essential amino acids in useful proportions and are highly digestible. Most plant proteins are limiting in one amino acid: grains in lysine, legumes in methionine. Combining them across the day, not necessarily in the same meal, resolves this completely.
Leucine is the amino acid that triggers muscle protein synthesis, and roughly 2.5–3 g per meal is the threshold. Whey, dairy and meat reach it easily; plant sources typically need a larger serving.
Concerns Worth Dismissing
The claim that high protein damages healthy kidneys has been tested repeatedly and not supported — intakes up to 2.8 g per kg show no adverse effect on renal function in healthy people. Those with existing kidney disease are a genuine exception and should follow medical advice.
Protein's effect on bone is likewise the opposite of the old claim: higher intakes are associated with better bone density, particularly in older adults.
Protein and Ageing
Anabolic resistance means older adults need more protein per meal to produce the same muscle response — roughly 1.2–1.6 g per kg daily, with 30–40 g per meal rather than 20–25. Combined with resistance training, this is the most effective intervention available against sarcopenia.
Frequently Asked Questions
Can I eat too much protein?
Excess protein is used for energy or stored, like any macronutrient. The practical limit is that protein displaces carbohydrate and fat in the diet, which can hurt training performance well before any health concern arises.
Do I need a protein shake?
No — it is food in a convenient form, useful when whole food is impractical. A scoop of whey is about 24 g for roughly the cost of a chicken breast.
Does the timing around workouts matter?
Far less than once believed. The "anabolic window" is now understood to span several hours. Total daily protein and consistent training matter enormously more than eating within 30 minutes of finishing.