Home / Guides / Protein Intake
Nutrition Guide

How Much Protein Do You Really Need?

The RDA is the amount that keeps you alive. These are the numbers that help you build muscle, hold onto it in a diet, and stay full doing it.

✍️ By Filip Mesec 🔄 Last updated 11 June 2026 ⏱ 7 min read ✅ Evidence-based
🔬 Meta-analysis backed

Why the RDA Isn't Enough

The official RDA for protein is 0.8g per kilogram of body weight per day. That number was never designed to optimise anything — it's the minimum estimated to prevent deficiency in sedentary adults. It answers the question "how little protein can most people survive on?", not "how much protein helps me train, recover, and build muscle?"

For people who lift, the evidence points much higher. The widely cited 2018 meta-analysis by Morton and colleagues in the British Journal of Sports Medicine — pooling 49 resistance-training studies with over 1,800 participants — found that protein supplementation enhanced gains in strength and lean mass, with benefits plateauing at around 1.6g/kg/day on average. Because individuals vary, the upper end of the confidence interval pushes the practical recommendation to roughly 1.6–2.2g/kg.1

Quick translation: for an 80kg (176lb) lifter, that's roughly 130–175g of protein per day — about double to triple what the RDA suggests.

Protein matters in both directions

  • In a calorie deficit — adequate protein is the single biggest dietary lever for keeping muscle while you lose fat. Diets that cut calories but skimp on protein lose more lean mass.
  • In a surplus — building new muscle tissue requires raw material. Training provides the stimulus; protein provides the bricks.
  • At maintenance — higher protein improves satiety and slightly raises energy expenditure, making weight easier to manage without conscious restriction.

How It Works

Protein isn't just "food for muscles" — four mechanisms explain why intake and distribution both matter:

1
MPS vs MPB balance. Your muscle is constantly being built (muscle protein synthesis) and broken down (muscle protein breakdown). You gain muscle only when synthesis exceeds breakdown over time. Eating protein raises MPS for several hours; training amplifies and extends that response. Chronic low intake tips the balance toward breakdown.
2
The leucine threshold. MPS is switched on when blood leucine — one essential amino acid — crosses a threshold, which takes roughly 2–3g of leucine, or about 0.4g/kg of quality protein in a meal.2 Tiny protein doses spread thinly all day may never fully trigger the response; this is why per-meal dose matters, not just the daily total.
3
Satiety and the thermic effect. Protein is the most filling macronutrient and the most expensive to digest — around 20–30% of its calories are burned during processing, versus roughly 5–10% for carbs and 0–3% for fat. Higher-protein diets reliably reduce spontaneous calorie intake, which is half the reason they work so well for fat loss.
4
Muscle retention in a cut. In a calorie deficit, the body looks for amino acids to fuel essential processes — and underfed muscle is a convenient source. High protein intake supplies those amino acids from food instead, sparing lean mass. This is why protein needs go up, not down, when dieting.

Total intake still rules

Distribution and timing are refinements, not foundations. Research consistently shows that hitting your total daily protein target explains most of the outcome; the "anabolic window" around workouts is far wider and more forgiving than supplement marketing suggests. Get the daily number right first, then spread it sensibly.

How Much, When, and From What

1.6–2.2g/kg
Daily target range
For building or keeping muscle
0.4g/kg
Per meal
Across 3–5 meals per day
2.4–2.7g/kg
Very lean, in a deficit
Contest prep / final fat-loss phase

Picking your number

  • General health, mostly sedentary — 1.2–1.6g/kg already improves on the RDA for satiety and muscle retention with age.
  • Lifting to build muscle — 1.6–2.2g/kg. There's no strong evidence the top of the range builds more muscle than the bottom, but it costs nothing in safety and adds insurance.
  • Dieting while already lean — the leaner you are and the harder the deficit, the more protein protects muscle. Intakes of 2.4–2.7g/kg have been used in research on lean, resistance-trained subjects in aggressive deficits.
  • Very overweight — don't multiply by total body weight. Base your target on lean body mass (or your target healthy weight); otherwise the math overshoots, since fat tissue needs almost no protein.

Plant vs animal protein

Animal proteins (meat, fish, dairy, eggs) are "complete" — they contain all essential amino acids in proportions close to what muscle needs, with high leucine content and digestibility. Most single plant proteins are lower in one or more essential amino acids and slightly less digestible. None of this makes plant-based muscle building impossible — it just changes the playbook:

  • Aim for the higher end of the range (≈2.0–2.2g/kg) if fully plant-based.
  • Combine complementary sources — legumes + grains (rice and beans, hummus and pita) cover each other's gaps.
  • Soy, pea, and blended powders perform comparably to whey in training studies when total protein is matched.
Practical advice: Set a daily target of 1.6–2.2g/kg (lean mass if very overweight), split it into 3–5 meals of roughly 0.4g/kg each, and anchor every meal around a protein source first. That alone covers ~90% of what the science can offer.

Put It Into Practice

Skip the mental math — the FitCalc toolkit turns these ranges into your personal daily numbers in under a minute.

🍗Protein CalculatorYour daily target in grams 🍽️Calories & MacrosBuild your full macro split 🔥TDEE CalculatorFind your maintenance calories

Frequently Asked Questions

Does a high-protein diet damage your kidneys?

Not in healthy people. The kidney-damage idea came from studies of patients with pre-existing kidney disease, where protein restriction is sometimes used to manage the condition. Controlled trials in healthy adults — including resistance-trained people eating well above 3g/kg for a full year — have found no harmful effects on kidney function.3 If you have diagnosed kidney disease, follow your doctor's guidance; otherwise, intakes in the 1.6–2.2g/kg range are considered safe.

Is eating too much protein harmful?

For healthy adults, there's no good evidence that protein intakes within the ranges athletes actually use (up to roughly 2.5–3g/kg in trained populations studied over months) cause harm. The realistic downsides are practical: excess protein calories still count toward your total, very high intakes can crowd out carbohydrate and fat you need for training and hormones, and it gets expensive. More protein beyond about 1.6–2.2g/kg simply stops adding muscle-building benefit.

Do I really need protein at every meal?

Total daily protein matters most, but distribution helps. Muscle protein synthesis responds to a per-meal dose of roughly 0.4g/kg of quality protein, and the response is capped per sitting — eating your entire daily target in one meal doesn't produce the same total stimulus as spreading it across 3–5 meals. Aim for 3–4 protein-containing meals as a practical default; perfection isn't required.

Is plant protein as good as animal protein?

It can be, with small adjustments. Plant proteins tend to be lower in leucine and some essential amino acids and slightly less digestible, so a fully plant-based eater should aim for the higher end of the intake range (around 2.0–2.2g/kg), combine complementary sources like legumes and grains, and consider soy, pea, or blended protein powders — which compare well to whey in resistance-training studies when total dose is matched.

Should I calculate protein from total body weight if I'm very overweight?

No — fat tissue needs very little protein, so multiplying 2g/kg by a high total body weight overshoots considerably. If your BMI is well into the obese range, base your target on lean body mass or on an adjusted weight (roughly your target healthy weight). For most very overweight people this works out to about 1.6–2.4g per kilogram of lean mass per day while dieting.

References

This guide is built from peer-reviewed research. Key sources:

  1. Morton RW, Murphy KT, McKellar SR, Schoenfeld BJ, Henselmans M, Helms E, Aragon AA, Devries MC, Banfield L, Krieger JW, Phillips SM. A systematic review, meta-analysis and meta-regression of the effect of protein supplementation on resistance training-induced gains in muscle mass and strength in healthy adults. British Journal of Sports Medicine. 2018;52(6):376–384. PubMed
  2. Moore DR, Robinson MJ, Fry JL, Tang JE, Glover EI, Wilkinson SB, Prior T, Tarnopolsky MA, Phillips SM. Ingested protein dose response of muscle and albumin protein synthesis after resistance exercise in young men. American Journal of Clinical Nutrition. 2009;89(1):161–168. PubMed
  3. Antonio J, Ellerbroek A, Silver T, Vargas L, Tamayo A, Buehn R, Peacock CA. A High Protein Diet Has No Harmful Effects: A One-Year Crossover Study in Resistance-Trained Males. Journal of Nutrition and Metabolism. 2016;2016:9104792. PubMed

About the Author

FM
Written by Filip Mesec

Founder of FitCalc. Filip researches and writes FitCalc's training and nutrition guides, building each one from the peer-reviewed literature cited above and flagging clearly where the evidence is limited or contested. FitCalc's guides are educational and are not a substitute for personalised advice from your doctor or a registered dietitian.