Protein recommendations online range wildly — anywhere from 0.8g to 3g+ per kilogram of bodyweight, depending on who you ask. Most of that confusion comes from mixing up different goals: general health, building muscle, and losing fat all have different targets. Here's what the actual research says for each.
The baseline: general health
The official minimum — the RDA (Recommended Dietary Allowance) — is 0.8g of protein per kg of bodyweight per day. This is genuinely a minimum, not a target: it's the amount needed to avoid deficiency in a sedentary adult, not the amount that supports an active lifestyle or training goals. If you train regularly, this number is too low for you.
Building muscle
Research consistently points to a range of 1.6–2.2g per kg of bodyweight per day for building muscle, with most sports nutrition bodies (including the International Society of Sports Nutrition) landing in a similar 1.6–2g range. Going meaningfully above 2.2g/kg hasn't been shown to provide extra muscle-building benefit — more isn't better past a certain point, it just becomes harder to fit into your diet for no additional gain.
Example: an 80kg (176lb) person aiming to build muscle would target roughly 128–176g of protein per day.
Losing fat while preserving muscle
If you're in a calorie deficit, protein needs actually go up, not down — research suggests 1.6–2.4g per kg during fat loss, toward the higher end of that range if the deficit is aggressive. Higher protein intake during a cut helps preserve muscle mass that would otherwise be at risk when calories are restricted, which is part of why "just eat less of everything" tends to produce worse body composition outcomes than a structured, protein-prioritised cut.
Does protein source matter?
For total muscle-building effect, research suggests that as long as total daily protein intake is high enough (1.6g/kg or above), the source — animal or plant-based — doesn't meaningfully change outcomes. Vegans and vegetarians don't need to eat more protein than omnivores to build the same muscle, provided they're hitting a similar total gram target and getting a reasonably complete amino acid spread across the day (which is easier with combined plant sources — see our guide on [vegan protein]).
Timing: does it actually matter?
Total daily intake matters far more than precise timing. That said, spreading protein across 3–4 meals, each with roughly 0.3g per kg of bodyweight (about 20–40g for most people), appears to support muscle protein synthesis more consistently than getting the same daily total from one or two large meals. The idea of a strict "anabolic window" immediately post-workout has been largely overstated in older fitness marketing — what matters more is hitting your daily total consistently.
A simple way to calculate your target
- Find your bodyweight in kg (divide lbs by 2.2 if needed)
- Multiply by your target range:
- General health: 0.8g/kg
- Building muscle: 1.6–2.2g/kg
- Cutting/fat loss: 1.6–2.4g/kg
- Spread that total across 3–4 meals or shakes through the day
FAQs
Can I eat too much protein? For most healthy adults, there's no strong evidence that protein intake up to around 3.5g/kg causes harm, though there's little additional benefit above roughly 2.2g/kg for muscle building specifically. If you have an existing kidney condition, check with a doctor before significantly increasing protein intake.
Do I need a protein shake, or can I get this from food alone? Food alone is entirely sufficient if you can consistently hit your target that way. Protein powder is a convenience tool for closing the gap when meals fall short — not a requirement. It tends to become genuinely useful once daily targets climb above what's easy to hit through meals alone (roughly 150g+ for many people).
Is 1g of protein per pound of bodyweight the same as the research-backed range? Close — 1g per lb works out to about 2.2g per kg, which sits at the top of the muscle-building range. It's a popular, easy-to-remember rule of thumb, and not far off the evidence, though the actual research range (1.6–2.2g/kg) starts lower than that.
Does protein need change with age? Older adults generally benefit from protein intake at the higher end of these ranges, since the body becomes somewhat less efficient at using protein for muscle maintenance with age (a phenomenon sometimes called anabolic resistance).
Struggling to hit your daily target through food alone? See our Whey Blend range for an easy way to close the gap, or read our Whey Concentrate vs Isolate vs Hydrolysed guide to choose the right type for your goal.
This article provides general nutritional information and isn't a substitute for personalised advice. If you have a health condition affecting protein metabolism (e.g. kidney disease), speak with a doctor or registered dietitian before making significant changes to your intake.