How Much Protein Do You Need? The Science by Body Weight and Goal

The honest answer to how much protein you need isn’t a single flat number — it scales with body weight and activity level, which is why a 70kg sedentary adult and an 85kg strength-training adult have genuinely different targets.

The formula

Worked examples

A 70kg moderately active person: 70 × 1.6 = 112g/day. An 85kg person training hard to build muscle: 85 × 2.0 = 170g/day. The Protein Intake Calculator applies the same multiplier table to your own weight and activity level.

Protein quality: not all sources are equal

The multiplier-based target in this article treats a gram of protein as a gram of protein, but protein quality varies by source based on its amino acid profile and digestibility. Animal proteins (meat, dairy, eggs) are generally “complete” — containing all essential amino acids in proportions the body uses efficiently — while some plant proteins are lower in one or more essential amino acids individually, though combining varied plant sources across a day (legumes with grains, for instance) typically closes that gap. This is a real consideration for diet quality, though it’s secondary to hitting an adequate total gram target in the first place.

Why the RDA is a floor, not a target for active people

The 0.8g/kg Recommended Dietary Allowance is the amount shown to prevent deficiency in a largely sedentary reference population — it’s a safety minimum, not a target optimized for athletic performance or muscle growth. Research reviews on protein needs for resistance-trained individuals — including a widely cited meta-analysis published in the British Journal of Sports Medicine — generally support intakes in the 1.6-2.2g/kg range for maximizing muscle protein synthesis, well above the basic RDA.

Practical ways to hit a higher protein target

For anyone whose current diet falls well short of a calculated target, closing the gap gradually tends to be more sustainable than an abrupt jump. Anchoring protein to each main meal — a palm-sized portion of meat, fish, eggs, dairy or a plant-protein equivalent at breakfast, lunch and dinner — is a simple heuristic that gets most people most of the way to a reasonable daily total without needing to track grams precisely at every meal. Protein supplements (whey, casein, or plant-based powders) are a convenient way to close a remaining gap, though they’re a tool for convenience, not a requirement — whole-food sources can meet the same targets for anyone willing to plan meals around it.

Using bodyweight vs. lean body mass

For most people, total bodyweight is a reasonable basis for this calculation. But for someone with a notably higher or lower body-fat percentage than average, lean body mass can be a more precise basis, since protein needs track muscle tissue more directly than they track fat mass — a person carrying significant extra fat mass doesn’t need proportionally more protein just because their total bodyweight is higher.

Basis	Best suited for
Total bodyweight	Most people, simple and close enough
Lean body mass	Notably higher or lower body-fat percentage than average

Timing and distribution matter alongside the total

Hitting a daily protein total is the primary driver of most protein-related outcomes, but research on muscle protein synthesis also points to distribution mattering somewhat: spreading protein intake across three to four meals — rather than concentrating most of it into a single meal — appears to support more consistent muscle protein synthesis throughout the day than the same total eaten in one sitting. This is a secondary consideration compared to the daily total, but a genuinely useful one for anyone who currently eats very little protein at breakfast and a large amount at dinner.

Protein needs during a calorie deficit

Protein targets often get raised, not lowered, during a calorie deficit — a seemingly counterintuitive choice, since overall food intake is going down. The reasoning is that adequate protein helps preserve lean muscle mass while losing weight, which is exactly what most people trying to lose fat actually want to happen (losing fat, not muscle). This is why many evidence-based fat-loss protocols push protein intake toward the higher end of the 1.6-2.2g/kg range specifically during a deficit, even as total calories fall.

Fitting protein into a full macro plan

A protein gram target is usually the starting point for a full macro plan, not the whole plan — once protein grams are set, the Macro Calculator can convert your remaining calorie budget into a carb/fat split around that fixed protein number.

FAQ

Is more protein always better for muscle growth? No — intake above roughly 2.2g/kg generally shows diminishing returns for muscle protein synthesis in most research; more isn’t harmful for most healthy people, but it isn’t proportionally more effective either.

Should I use total bodyweight or lean body mass for this calculation? Total bodyweight is fine for most people; lean body mass is more precise for someone with notably higher or lower body fat than average, since it more directly tracks muscle tissue.

Do plant-based protein sources require a higher target? Some research suggests a modest increase can help offset generally lower digestibility and incomplete amino acid profiles in some plant proteins, though a varied plant-protein diet can meet the same targets as an omnivorous one.

Does protein timing around workouts matter as much as total daily intake? Total daily intake matters considerably more — the once-popular idea of a narrow post-workout “anabolic window” has been substantially walked back by more recent research, which finds total daily protein and its distribution across the day matter more than precise workout-adjacent timing.

Should protein intake change during a calorie deficit? Many evidence-based approaches actually raise the protein percentage (or keep the gram target steady while calories fall) during a deficit specifically to help preserve lean muscle mass while losing fat.