Protein is the most discussed macronutrient in fitness, and for good reason: it plays a central role in building and maintaining muscle, managing hunger, and supporting metabolic health. But the question of how much protein you actually need is surrounded by contradictory advice, from government guidelines that seem too low to gym culture maximums that seem impossibly high.

This guide walks through what the current research actually says.

The official recommendation vs. what the research shows

The officially recommended dietary allowance (RDA) for protein in most countries is 0.8 grams per kilogram of body weight per day. This figure is often cited as the "amount you need," but it is more accurately described as the minimum required to prevent deficiency in sedentary adults — not the optimal amount for health, body composition, or performance.

The research on protein requirements for active individuals paints a very different picture. Multiple large-scale meta-analyses, including a widely cited 2018 analysis published in the British Journal of Sports Medicine that pooled data from 49 studies, found that muscle gain was maximised at approximately 1.62 grams of protein per kilogram of body weight per day, with diminishing returns beyond this point.

The evidence-based range: For most active people — regardless of whether the goal is fat loss, muscle gain, or general health — an intake of 1.6–2.2g of protein per kilogram of body weight covers nearly every scenario.

Protein needs by goal

For fat loss

Protein becomes even more important during a calorie deficit. When calories are restricted, the body is at greater risk of breaking down muscle tissue for energy. Higher protein intake helps preserve lean mass, which is important both for aesthetics and for maintaining metabolic rate during a cut.

During fat loss phases, the evidence supports 1.8–2.4g/kg, with higher intakes being beneficial for leaner individuals and those doing significant amounts of resistance training. Protein is also the most satiating macronutrient, helping manage hunger on a reduced calorie intake.

For muscle building

For a person in a calorie surplus who is training for hypertrophy, hitting 1.6–2.0g/kg is generally sufficient to maximise muscle protein synthesis. Going higher than 2.2g/kg provides no additional muscle-building benefit based on current evidence, though it is harmless for healthy adults with functioning kidneys.

For maintenance and general health

For moderately active people who exercise 3–4 times per week without specific body composition goals, 1.2–1.6g/kg maintains muscle mass and supports recovery. Even sedentary older adults benefit from higher protein intakes than the RDA — research suggests 1.0–1.2g/kg helps slow the age-related loss of muscle mass (sarcopenia).

Quick reference table

GoalRecommended intakeFor a 75kg person
General health (active)1.2–1.6 g/kg90–120g/day
Fat loss1.8–2.4 g/kg135–180g/day
Muscle building1.6–2.0 g/kg120–150g/day
Older adults (65+)1.0–1.2 g/kg75–90g/day

Does the source of protein matter?

Protein quality refers to the amino acid profile and how easily the body can use the protein it contains. Animal proteins (meat, fish, eggs, dairy) are "complete" proteins, meaning they contain all nine essential amino acids in adequate quantities. Most plant proteins are "incomplete," lacking sufficient amounts of one or more essential amino acids.

This does not mean plant protein is inferior — it means plant-based eaters should eat a variety of protein sources throughout the day (combining legumes, grains, nuts, and seeds) to cover their full amino acid needs, and may benefit from slightly higher total protein intakes to account for lower digestibility.

High-protein food sources

  • Animal: Chicken breast (31g/100g), tuna (29g/100g), Greek yoghurt (10g/100g), eggs (13g/100g), cottage cheese (11g/100g), salmon (25g/100g)
  • Plant: Lentils (9g/100g cooked), black beans (9g/100g cooked), tofu (8g/100g), edamame (11g/100g), tempeh (19g/100g), seitan (25g/100g)

Is too much protein harmful?

For healthy adults with normal kidney function, high protein intakes (up to 3g/kg or more) have not been shown to cause kidney damage in clinical research. The idea that protein is harmful to kidneys comes from studies in people who already had pre-existing kidney disease, in whom high protein intake can exacerbate the condition. For healthy people, excess protein is simply metabolised and excreted.

The main practical downside of very high protein intakes is cost and the difficulty of hitting targets without exceeding calorie goals — not a physiological health concern.

Exception: If you have been diagnosed with chronic kidney disease or have a history of kidney stones, consult a healthcare professional before significantly increasing your protein intake.

Protein timing: does it matter?

Distributing protein across multiple meals is more effective than consuming the same total in one or two sittings. Research suggests that each meal containing 0.4–0.5g of protein per kilogram of body weight (roughly 30–40g for most people) maximises the muscle protein synthesis stimulus from that meal. Eating more than this in one sitting does not produce additional benefit in the short term.

Practically, this means aiming for 3–5 protein-containing meals or snacks spread throughout the day, with each providing an adequate dose of protein rather than concentrating it at dinner.

Summary

The RDA of 0.8g/kg is a minimum to prevent deficiency, not an optimal target. For anyone who exercises regularly, 1.6–2.0g of protein per kilogram of body weight per day is the evidence-based target for supporting muscle mass, managing hunger, and promoting recovery. Spread this across 3–5 meals, choose varied and quality sources, and adjust your total intake based on your specific goal.

Use our calculator to get a personalised daily protein target alongside your full calorie and macro breakdown.