How Much Protein Do You Need? Guide + Calculator

Ask ten gym-goers how much protein they eat and you'll get ten different answers. At least three will confidently cite a number they read on a forum in 2017 that has never been verified by a single peer-reviewed study.

The fitness world loves a protein myth. So let's cut through it.

Here's what the science actually says, how to apply it without turning every meal into a maths equation, and why the quality of your protein matters just as much as the quantity.

1. The Number Everyone Argues About

For years the gym-standard advice was "1 gram of protein per pound of bodyweight." Simple. Memorable. Also not particularly grounded in evidence.

The current scientific consensus — anchored by a meta-analysis and meta-regression of 49 studies — lands somewhere more nuanced:¹

1.6g to 2.2g of protein per kilogram of bodyweight per day for people actively training to build muscle.

How to read that range

This is where most articles get it backwards, so it's worth being precise.

The 1.6g/kg figure isn't the minimum you scrape by on. It's the point at which the meta-regression found additional protein stopped producing further gains. In other words, the bottom of the range is where most of the benefit already lives.¹

The 2.2g/kg upper figure comes from the confidence interval around that plateau. It's the conservative bound — the number you use when you want to be certain you're covered.

So moving up the range isn't about chasing a better result. It's insurance, and it's worth buying when one or more of these applies:

• You're training hard and frequently
• You're in a calorie deficit and want to protect lean mass¹³
• You're over 40, and especially over 65
• Your protein comes largely from lower-quality sources

If none of those apply, sitting near the bottom of your range is a perfectly evidence-based place to be. Eating 2.2g/kg when 1.7g/kg would do isn't harmful — it's just unnecessary effort and expense.

So if you weigh 75kg, you're looking at roughly 120g to 165g of protein per day. If you weigh 85kg, that's 136g to 187g.

If those numbers feel high, that's because they are — relative to what most people actually eat. The average British adult consumes around 75–85g of protein per day. That's fine for general health minimums, but it falls short for anyone seriously trying to support exercise recovery, or build and maintain muscle effectively.

2. Does It Matter When You Eat It?

Short answer: a bit, but less than you think — and far less than supplement marketing would have you believe.

The concept of the "anabolic window" — the idea that you have roughly 30 minutes post-workout to consume protein before your muscles stop responding — has been dramatically overstated. The window is considerably longer, likely several hours, and total daily protein intake matters far more than the precise minute you consume it.²

That said, there are sensible timing habits worth adopting:

• Post-workout protein is still a good idea — not because the window is closing, but because training creates the stimulus for repair, and having protein available sooner rather than later is logical.
• Spreading intake across meals works better than cramming it all in at once. Muscle protein synthesis responds strongly to around 30–40g in a sitting, with returns tapering after that.² Evenly distributed servings produce a higher 24-hour synthesis rate than a skewed pattern of one small, one moderate and one enormous meal.³⁴
• Before bed matters more than people think. Slow-digesting protein before sleep — or a fast-absorbing option if you train late — supports overnight recovery.

The practical takeaway: don't obsess about the exact minute of your post-workout protein. Do make sure you're consistently hitting your daily target across well-spread meals.

That consistency, compounded over weeks and months, is what actually builds muscle.

3. Not All Protein Is Created Equal

Here's the part most protein calculators don't tell you: hitting your gram target is only half the job. The other half is hitting it with complete protein — protein that contains all nine essential amino acids (EAAs).

Essential amino acids are the ones your body cannot manufacture on its own. They have to come from what you eat or supplement.

Of the nine, leucine deserves special mention. It's the primary trigger for muscle protein synthesis, the process by which your body actually builds new muscle tissue.⁵ Without adequate leucine, you can hit your gram target perfectly and still underperform on muscle building.

The nine EAAs are: leucine, isoleucine, valine, lysine, methionine, phenylalanine, threonine, tryptophan, and histidine. Together they form the complete toolkit your muscles need to repair, rebuild, and grow after training.

Animal proteins — whey, chicken, eggs, fish — are naturally complete, containing all nine EAAs in solid amounts. This is why they've historically dominated sports nutrition.

Most plant proteins are technically incomplete. Not missing EAAs entirely, but with certain ones present in suboptimal amounts. Pea protein is lower in methionine. Rice protein is lower in lysine.⁶⁷ This is the limitation plant-based athletes have worked around for years, typically by combining multiple protein sources.

4. Why Protein Quality Changes Your Target

Almost every protein calculator online asks for your weight, your training, and your goal — then hands you a number in grams. None of them ask what your protein is actually made of.

That's a meaningful omission, because a gram of protein on a label is not a fixed unit of anything useful. It's a measure of what went into the food, not what comes out the other end of digestion.⁹

Two proteins, same label, different outcome

Protein quality is formally scored using DIAAS — the Digestible Indispensable Amino Acid Score — which measures how much of a protein's essential amino acids are actually absorbed and available.⁸

Whey concentrate scores around 110. Pea protein concentrate scores around 73. Rice protein sits below 60. Under the FAO system, anything under 75 can't be classed as a "good source" of protein at all.

Run that through your daily target and the implication is uncomfortable. If your intake is built largely on sources scoring in the 70s rather than the 100s, the effective protein your muscles receive is meaningfully lower than the number you tracked.

Hit 140g on paper from low-quality sources, and you may be delivering the functional equivalent of 110–115g. That's not a rounding error — it can be the difference between sitting inside your target range and sitting below its floor.

There is a growing argument in the literature that protein requirements should be expressed in terms of available amino acids rather than raw grams, precisely because of this gap.¹⁰¹¹

Why this hits plant-based diets hardest

It isn't that plant protein doesn't work. It's that standard, unenriched plant sources lose ground on three axes at once: lower digestibility, an incomplete amino acid profile, and slower absorption.⁷

Analysis of plant-based meals in national dietary survey data shows the same pattern at the meal level, not just the ingredient level — plant-based meals frequently deliver less usable protein than their gram content suggests.¹²

Stack those together and a plant-based eater tracking 1.8g/kg can be functionally operating at closer to 1.4–1.5g/kg — below the threshold where the research shows the benefit plateau sits.

They did everything the calculator told them. The calculator just asked the wrong questions.

What reduces the gap

The correction runs in the other direction too, which is the useful part. Improving quality lowers the total grams you need to hit the same physiological outcome:

• EAA enrichment — adding back the specific amino acids a source is short on brings the profile to or beyond whey's, so fewer grams do more work
• Hydrolysis — pre-broken peptides absorb faster and more completely, reducing what passes through unused
• Source blending — pea with rice covers some of each other's gaps, though it improves the profile without completing it
• Leucine density — each serving clearing roughly 2.5g of leucine matters more than the total gram count on its own

This is why "how much protein do I need?" is genuinely unanswerable without knowing where the protein is coming from.

5. How Age Changes the Equation

Protein requirements are not static across a lifetime, and the direction of travel surprises people. You need more as you get older, not less — at exactly the point most people start eating less of it.

Anabolic resistance

The mechanism has a name: anabolic resistance. Ageing muscle responds less readily to the same dose of protein. A serving that produces a solid muscle protein synthesis response at 25 produces a blunted one at 70.¹³

The muscle isn't broken. It just needs a stronger signal to reach the same result — which in practice means more protein per serving, and more leucine within that serving, to cross the same threshold.

What that means in numbers

Two things shift with age:

• The daily total goes up. Where 1.2g/kg is a reasonable maintenance figure for a younger adult, older adults generally need more than that just to hold onto existing muscle — before any training goal is factored in.
• The per-serving amount matters more. Younger muscle can make reasonable use of a smaller serving. Older muscle needs a larger one to trigger the same response, so an even distribution across the day becomes more important, not less.⁴

This is also where protein quality compounds hardest. If older muscle needs a stronger signal, and lower-quality protein delivers a weaker one, the two effects multiply rather than add. An older adult on a mostly plant-based diet without enrichment faces both problems at once.

The practical version

If you're over 40, nudge your target upward. If you're over 65, treat protein as a priority nutrient rather than a background one, spread it evenly across the day rather than loading it into one evening meal, and pay attention to whether each serving is actually complete.

Resistance training remains the strongest available counter to anabolic resistance. Protein supports it — it doesn't replace it.

6. Protein Calculator: Build Your Plan

Most calculators give you one number. This one gives you two: your baseline target, and what that target becomes once your protein sources are accounted for.

7. The EAA Enrichment Difference

A well-formulated plant protein supplement doesn't just throw some hydrolysed pea protein in a tub and call it complete. It specifically adds the essential amino acids that plant sources are naturally short on — leucine, methionine, and others — bringing the full EAA profile up to, and in some cases beyond, what whey delivers.

The result is a plant protein that functions like an animal protein at the muscle level.

Your body doesn't know the difference between an EAA derived from pea protein and one added through enrichment. Amino acids are amino acids. What matters is whether all nine are present in the right amounts.

Think of it like a recipe. If a dish calls for nine spices and you only have seven, it won't taste quite right no matter how well you cook it. Adding the two missing spices — wherever they came from — fixes the recipe.

For anyone trying to build muscle on a plant-based diet, this distinction is enormous. It means you don't have to compromise on amino acid completeness to avoid dairy. You just have to choose a product that's been formulated properly.

8. Where Clear Protein Fits Into Your Daily Target

Here's where the practical and the scientific come together.

Building muscle requires hitting your target consistently — not just on training days, not just when you remember, but every day. And the biggest enemy of consistency isn't motivation. It's palatability.

People abandon protein supplements for two reasons: they don't like the taste, or they find them too heavy to drink when they need them most.

Both problems are more common than the supplement industry likes to acknowledge, and both produce the same outcome — people chronically under-hitting their protein targets because the experience of meeting them is unpleasant.

A 25g serving of clear protein in a light, fruity drink is something you can slot in at any point:

• Mid-morning, when you want something light between meals
• During training, as an intra-workout amino acid top-up
• Post-workout, when you're tired, warm, and a thick shake is genuinely unappealing
• On a hot day, when a cold passion fruit drink sounds good and a chocolate milkshake does not

That last point deserves more credit than it gets. Supplement compliance is a real issue, and people who find their protein enjoyable consume it more consistently — which over months is what drives actual muscle development.

A supplement you want to drink every day is categorically more effective than a better-formulated one you force down three times a week.

9. Putting It All Together

Here's how to approach your protein intake without overthinking it.

10. The Bottom Line

Building muscle requires more protein than most people eat — around 1.6–2.2g per kg of bodyweight, spread throughout the day, from complete amino acid sources. The lower end of that range is where the evidence plateaus; the upper end is headroom you buy when training, age, a deficit, or source quality demand it.

Timing matters less than total intake. Quality decides how much of that intake actually counts. Consistency matters more than any of it.

And consistency, in nutrition, almost always comes down to whether you enjoy what you're eating and drinking.

There's no virtue in forcing down a protein shake you hate every day for two years. If the format you're using doesn't work for you, the format is the problem — not your willpower.