How Much Protein Do You Need to Build Muscle? (Science-Based Guide + Daily Targets)
Why protein is the second pillar of muscle growth (alongside progressive overload)
If you want to build muscle, two things do most of the heavy lifting: a training stimulus that gets progressively harder over time, and enough protein to repair and rebuild what that training breaks down. Progressive overload tells your body that it needs to grow. Protein supplies the raw material to actually do it.
Resistance training elevates muscle protein synthesis — the process of building new muscle tissue — for up to a full day afterward. But synthesis only outpaces breakdown when you feed it. Without sufficient dietary protein, you can train perfectly and still stall, because your body never has a consistent surplus of amino acids to grow with.
💡 Key Principle
Protein is the only macronutrient that directly supplies the amino acids your muscles are built from. Train hard, then give your body the bricks — both are required, and neither works without the other.
The good news: the science here is unusually clear. We have a large meta-analysis pinpointing how much protein you actually need, and position stands from sports nutrition bodies that agree on the practical numbers. This guide turns that evidence into daily targets you can hit today.
How much protein do you actually need per day?
The science: 1.6–2.2 g of protein per kg of bodyweight
The most-cited number in modern strength nutrition comes from a 2018 meta-analysis by Morton and colleagues, which pooled 49 studies and 1,863 participants. It found a breakpoint at 1.62 g of protein per kg of bodyweight per day (95% CI 1.03–2.20) — beyond this point, eating more protein produced no further gains in fat-free mass.
That single finding is where the popular "1.6–2.2 g/kg" rule comes from. Roughly 1.6 g/kg covers the needs of most lifters, while ~2.2 g/kg is the prudent upper end of the confidence interval — useful as a ceiling for people who are very lean, very advanced, or simply want a safety margin. Going beyond that isn't harmful, but it isn't buying you extra muscle either.
It also drives strength, not just size
In the same meta-analysis, adding protein supplementation on top of resistance training increased one-rep-max strength by an average of 2.49 kg (95% CI 0.64–4.33) versus training alone. Protein doesn't just help you look bigger — it helps you lift heavier.
The International Society of Sports Nutrition (ISSN) position stand lands in the same neighbourhood, stating that an overall intake of 1.4–2.0 g/kg/day is sufficient for most exercising individuals to build and maintain muscle. Between Morton's breakpoint and the ISSN range, 1.6–2.2 g/kg is a safe, evidence-backed target.
Quick math: calculating your personal daily target
You only need your bodyweight in kilograms and a multiplier. To convert pounds to kilograms, divide by 2.2.
✅ HOW TO CALCULATE YOUR TARGET
- 📏 Step 1: Take your bodyweight in kg (e.g. 75 kg).
- ✖️ Step 2 (lower end): 75 × 1.6 = 120 g of protein per day.
- ✖️ Step 3 (upper end): 75 × 2.2 = 165 g of protein per day.
- 🎯 Your range: aim somewhere between 120 g and 165 g daily.
For a typical 75 kg lifter, that works out to roughly 120–165 g of protein per day. Split across four meals, that's about 30–41 g per meal — a target most people can hit with normal food and a little planning. If you're carrying significant body fat, basing the calculation on a target or lean bodyweight rather than total scale weight will keep the number realistic.
Cutting, maintaining or bulking — does the number change?
When you're maintaining or bulking (eating at or above maintenance calories), the 1.6–2.2 g/kg range is plenty. You have an energy surplus, so your body isn't tempted to burn muscle for fuel.
Cutting changes things. In a calorie deficit, protein needs go up to protect the muscle you've already built. Helms and colleagues (2014) reviewed lean, resistance-trained athletes in a deficit and recommended 2.3–3.1 g/kg of fat-free mass, scaling toward the top of that range as the deficit gets steeper and the athlete gets leaner. The ISSN echoes this, noting intakes of 2.3–3.1 g/kg/day may be needed to retain lean body mass in resistance-trained subjects during hypocaloric periods.
✨ Quick rule of thumb
Bulking or maintaining: 1.6–2.2 g/kg of bodyweight. Cutting (especially if lean): push toward 2.3–3.1 g/kg of fat-free mass. The leaner you are and the harder you're dieting, the higher you go.
Does protein timing and per-meal distribution matter?
The 'anabolic window' myth vs. total daily intake
For years, lifters rushed a shake down within 30 minutes of finishing a set, terrified of missing the "anabolic window." The evidence has since deflated that panic. The ISSN notes that the anabolic effect of a workout lasts at least 24 hours, though it diminishes the further you get from the session.
In other words, the window is a barn door, not a keyhole. Total daily protein intake matters far more than nailing a narrow post-workout slot. Hit your daily number and you've already captured the vast majority of the benefit — whether your post-lift meal arrives in 20 minutes or two hours makes little practical difference for most people.
Spreading protein across 3–5 meals (~0.4 g/kg per meal)
While exact timing is overrated, distribution still matters. Your body can only use so much protein to build muscle in one sitting, so spreading intake out beats dumping most of it into one giant dinner.
Mamerow and colleagues (2014) tested this directly. Eating protein evenly (~30 g at breakfast, lunch and dinner) produced a 24-hour muscle protein synthesis rate 25% higher (0.075 vs 0.056 %/h) than skewing most of the day's protein toward the evening meal — even though total daily protein was identical in both groups.
✨ How much per meal?
📐 The ISSN guideline
Roughly 0.25 g/kg per meal, or an absolute dose of 20–40 g, every 3–4 hours across the day.
📈 The upper-end approach
Schoenfeld & Aragon (2018) suggest about 0.4 g/kg per meal across at least four meals to maximise the daily anabolic response.
There's also a quality angle. Leucine is the amino acid that flips the muscle-building switch, and the ISSN advises each protein dose contain roughly 700–3,000 mg of leucine to maximally stimulate synthesis. Practically, that means leaning on complete, leucine-rich sources — which we'll cover next.
A useful extra dose: pre-sleep protein
The ISSN notes that 30–40 g of casein before bed increases overnight muscle protein synthesis without negatively affecting fat metabolism. It's an easy way to add an anabolic feeding during the longest fasting window of your day.
Best protein sources to hit your target
Animal sources and complete proteins
Animal proteins are "complete" — they contain all nine essential amino acids in ratios close to what your muscles need, and they're naturally rich in the leucine that drives synthesis. For most lifters they're the easiest way to hit both your daily total and the per-meal leucine threshold.
✅ HIGH-QUALITY ANIMAL SOURCES (approx. protein per 100 g cooked)
- 🍗 Chicken breast: ~31 g — lean, cheap, versatile.
- 🥩 Lean beef: ~26 g — plus iron, zinc and creatine.
- 🐟 Salmon / white fish: ~22–25 g — fish adds omega-3s.
- 🥚 Eggs: ~13 g (about 6 g per egg) — a leucine-dense staple.
- 🧀 Greek yogurt & cottage cheese: ~10–11 g — great for evenings (casein-rich).
Plant-based and vegetarian options
You can absolutely build muscle on a plant-based diet — it just takes a little more planning. Most individual plant proteins are lower in one or more essential amino acids (often leucine or lysine), so the strategy is to eat a bit more total protein and combine sources across the day so the gaps fill in.
✅ STRONG PLANT-BASED SOURCES
- 🌱 Soy (tofu, tempeh, edamame): a complete protein and one of the most leucine-rich plant options.
- 🫘 Lentils & beans: ~9 g per 100 g cooked, plus fibre.
- 🌾 Seitan: very high protein (~25 g per 100 g), though low in lysine — pair with legumes.
- 🥜 Pea/soy protein powders: an easy way to top up leucine to the per-meal threshold.
Do you need protein powder or supplements?
No — but it helps. Whey, casein and plant powders are simply convenient, concentrated food, not magic. If you can hit 1.6–2.2 g/kg with whole foods, a shaker is optional. The reason most lifters keep one around is practicality: it's hard to stomach four large meat-and-veg meals a day, and a 25–30 g scoop closes the gap in seconds.
Older lifters may need a bigger dose
The ISSN notes that a 40 g dose of whey isolate is needed to maximise muscle protein synthesis in the elderly, versus the 20 g that suffices in younger adults — an effect known as "anabolic resistance." If you're over 60, aim for the higher end of each per-meal serving.
How to track protein without overcomplicating it
Tracking protein sounds tedious, but you don't need to weigh every meal forever. The goal is to build accurate intuition, then let go of the precision.
📋 A simple 3-step approach
Step 1 — Set one number
Calculate your daily target once (bodyweight × 1.6 to 2.2) and write it down. That single number is what you're chasing.
Step 2 — Track for 1–2 weeks
Log everything you eat for a couple of weeks using a food app. Almost everyone discovers they were eating less protein than they assumed.
Step 3 — Estimate by hand
Once you know what a 30–40 g serving looks like, switch to eyeballing it: a palm of meat, a scoop of powder, a tub of Greek yogurt. Re-check with the app occasionally.
A practical shortcut: aim for a solid protein source at every meal. If breakfast, lunch, dinner and a snack each contain 30–40 g, you'll land in range without doing arithmetic at the table.
Protein alone won't build muscle — connecting nutrition to training progress
Here's the trap: it's easy to obsess over grams of protein while ignoring whether you're actually getting stronger. Protein is a permissive factor — it allows growth — but the stimulus that demands growth is progressively harder training. Eat 200 g a day with no progressive overload and you'll mostly just have expensive pee.
The only honest way to know your nutrition is working is to watch your training numbers trend upward over weeks and months. If your protein is dialled in and your loads, reps and weekly volume are climbing, the system is working. If they're flat despite solid nutrition, the problem is usually in the gym (programming, effort, recovery), not on your plate.
Using Gainflow to verify your nutrition is translating into strength and volume gains
This is where logging your workouts pays off. Gainflow tracks the weight, reps and volume you lift over time and visualises the trend, so you can see at a glance whether your hard-won protein intake is converting into real progress — not just guess.
✨ What to watch alongside your protein
📈 Strength trend
Are your top sets and estimated 1RMs creeping up month over month? That's muscle (and neural adaptation) you can measure.
📊 Weekly volume
Total sets × reps × load per muscle group. Rising volume that you can recover from is the clearest sign your nutrition is supporting growth.
Pair a consistent protein target with a tracked, progressing program and you've built a feedback loop: nutrition fuels the work, the log proves the work is paying off, and the numbers tell you when to push harder.
Common protein mistakes that stall muscle growth
⚠️ Mistakes to avoid
❌ Underestimating how little you actually eat
Most people who "eat plenty of protein" land closer to 1.0 g/kg when they finally track it. Measure before you assume you're hitting 1.6 g/kg.
❌ Skewing all your protein to dinner
Mamerow (2014) showed even distribution produced 25% higher 24-hour synthesis than back-loading. Spread it across 3–5 meals instead of one big plate at night.
❌ Obsessing over the "anabolic window"
The post-workout effect lasts at least 24 hours. Stressing about a 30-minute shake while missing your daily total is fixing the wrong problem.
❌ Not raising protein on a cut
In a deficit you need more, not less — up to 2.3–3.1 g/kg of fat-free mass — or you'll burn off the muscle you're trying to keep.
❌ Chasing protein while ignoring training
No amount of protein builds muscle without a progressively harder stimulus. Track your lifts to confirm the nutrition is actually doing something.
FAQ: how much protein to build muscle
How many grams of protein per kg of bodyweight do I need to build muscle?
Aim for 1.6–2.2 g per kg of bodyweight per day. Morton et al.'s 2018 meta-analysis found gains in fat-free mass plateaued past a breakpoint of 1.62 g/kg, and the ISSN recommends 1.4–2.0 g/kg for most exercising people. For a 75 kg lifter that's about 120–165 g per day.
Can I eat too much protein?
For healthy individuals, eating above the recommended range isn't harmful — it just doesn't build extra muscle. The 1.62 g/kg breakpoint is where additional protein stops adding to fat-free mass, so going much beyond ~2.2 g/kg mostly wastes calories and money.
How much protein should I eat per meal?
Roughly 0.25 g/kg (or 20–40 g) every 3–4 hours, per the ISSN — with some researchers suggesting up to 0.4 g/kg per meal across four-plus meals. Each dose should ideally contain 700–3,000 mg of leucine, which is easy to hit with a palm-sized serving of meat, eggs, dairy or a scoop of whey.
Do I need protein powder?
No. Powder is convenient, not essential. If you can reach your daily target with whole foods, you don't need a supplement. It simply makes hitting high totals easier, and a 40 g whey dose is particularly useful for older lifters who need more per meal to overcome anabolic resistance.
Does protein timing around my workout matter?
Far less than people think. The anabolic effect of training lasts at least 24 hours, so total daily intake and even meal distribution matter much more than rushing a shake immediately after your last set.
Is Your Protein Actually Building Muscle?
Download Gainflow to log every set, track your strength and volume trends, and confirm that your nutrition is translating into real muscle and strength gains over time.
Sources
- Morton et al. (2018) — A systematic review, meta-analysis and meta-regression of the effect of protein supplementation on resistance training-induced gains in muscle mass and strength (British Journal of Sports Medicine / PMC)
- Jäger et al. (2017) — International Society of Sports Nutrition Position Stand: protein and exercise (JISSN / PMC)
- Mamerow et al. (2014) — Dietary protein distribution positively influences 24-h muscle protein synthesis in healthy adults (The Journal of Nutrition / PubMed)
- Helms et al. (2014) — A systematic review of dietary protein during caloric restriction in resistance trained lean athletes: a case for higher intakes (IJSNEM / PubMed)