How Much Protein Do You Actually Need in a Day? A No-BS Breakdown by Body Weight and Goal

If you've Googled this before, you've probably landed on five different numbers from five different sources. So let's actually sort through the research and give you a straight answer, broken down by what you're actually trying to achieve.

The RDA is a floor, not a target

The official Recommended Dietary Allowance (RDA) for protein is 0.8 grams per kilogram of body weight per day.(1) For a 70kg person, that's about 56g a day. Here's the catch nobody tells you: the RDA was designed as the bare minimum to prevent deficiency, not an optimal amount for someone who trains, wants to lose fat, or wants to build muscle.(1) If you're only hitting the RDA, you're covering your basic needs and nothing more.

By goal: what the research actually recommends

General health & maintenance: 1.0–1.2g per kg of body weight per day. This supports lean mass and overall metabolic health for people who are moderately active but not specifically training for a physique or performance goal.(2)

Building muscle: The American College of Sports Medicine, the Academy of Nutrition and Dietetics, and Dietitians of Canada all converge on 1.2–2.0g per kg per day to optimise training recovery and support muscle growth.(3) The International Society of Sports Nutrition backs a similar range of 1.4–2.0g per kg.(3)

Losing fat while keeping muscle: This is where protein needs actually go up, not down. When you're in a calorie deficit, your body is more likely to break down muscle for energy unless you give it enough protein to protect it. Research supports 1.6–2.2g per kg per day during a cut, and some evidence suggests pushing toward 2.0–2.6g per kg specifically during more aggressive fat loss phases.(4)

Older adults (65+): Muscle naturally declines with age, and ageing bodies also become less responsive to the protein they do eat – a phenomenon researchers call "anabolic resistance."(2) To counter this, around 1.2g per kg per day is generally recommended, which is meaningfully above the standard RDA.

A quick real-world example

Let's say you're 70kg and your goal is building muscle. At 1.6g/kg, that's 112g of protein a day. Spread across 4 meals, that's about 28g per meal – roughly one solid protein source plus a shake, not some enormous chicken-breast marathon.

The part people get wrong

More isn't always better past a certain point. Research suggests intakes above roughly 2g per kg per day don't provide meaningfully more muscle-building benefit for most people, and consistently very high intakes (1.07–1.6g/kg was classified as "high protein" in at least one study) haven't shown extra benefit over well-dosed moderate-high intakes.(4) Protein distribution across the day also matters more than most people realise – spreading 20-40g per meal across 4-5 meals keeps your body's muscle-building machinery switched on more consistently than cramming it all into one giant dinner.(5)

So what does this mean for your shaker?

A shake is one of the easiest ways to close the gap between what you're actually eating and what your goal requires, especially on busy days when hitting 100g+ from whole food alone is a lot of cooking and chewing. Figure out your target from the ranges above, track your food for a few days to see where you're actually landing, and use a shake to fill whatever's left over.

(1) RDA of 0.8g/kg established via nitrogen balance studies through the Dietary Reference Intakes process, National Academies of Sciences.
(2) Phillips SM, Chevalier S, Leidy HJ. "Protein 'requirements' beyond the RDA: implications for optimizing health." Appl Physiol Nutr Metab. 2016.
(3) American College of Sports Medicine, Academy of Nutrition and Dietetics, Dietitians of Canada joint position statement; International Society of Sports Nutrition position stand.
(4) Transparent Labs protein intake breakdown citing ISSN-aligned research ranges; Rose-Francis, cited in Healthline (2025), on high-protein intake classification.
(5) Meal protein distribution and muscle protein synthesis research, cited via ATHLEAN-X protein calculator sourcing.