To gain muscle, most people need between 1.6 and 2.2 grams of protein per kilogram of body weight per day. For a 180-pound (82 kg) person, that works out to roughly 130 to 180 grams daily. This range comes from meta-analyses of resistance-trained individuals and represents the zone where muscle protein synthesis is reliably maximized. Going below 1.6 g/kg leaves gains on the table; going above 2.2 g/kg doesn’t appear to help much more.
The Daily Target in Real Numbers
Multiple reviews of weightlifters and strength athletes converge on a range of 1.2 to 2.0 g/kg/day as the baseline for muscle growth, with more recent meta-analyses pushing the upper confidence limit to 2.2 g/kg/day. The practical sweet spot for most lifters falls at 1.6 g/kg/day or above. That 1.6 figure isn’t a hard ceiling, though. It’s the point where the average person captures most of the muscle-building benefit, while some individuals, particularly younger bodybuilders, continue to see returns up to 2.2 g/kg/day.
Here’s what that looks like in practice:
- 150 lb (68 kg) person: 109–150 g protein per day
- 180 lb (82 kg) person: 131–180 g protein per day
- 200 lb (91 kg) person: 146–200 g protein per day
These numbers assume you’re eating enough total calories to support growth. Protein alone won’t build muscle if you’re significantly underfueling. Research on weightlifters suggests that total energy intake of at least 44 to 50 calories per kilogram of body weight is needed alongside adequate protein for maximal hypertrophy.
How Much Protein Per Meal Actually Matters
You’ve probably heard that the body can only “use” 20 to 25 grams of protein at a time. That number comes from studies measuring the rate at which muscles ramp up protein building after a meal. In younger adults, 20 to 25 grams of high-quality protein does trigger a strong muscle-building response. But it’s not a hard cap. One study found that 40 grams of protein after a workout boosted the rate of muscle protein building by about 20% more than 20 grams did.
A more useful per-meal target is 0.4 g/kg of body weight. Spread that across at least four meals, and you naturally land at 1.6 g/kg/day. If you’re aiming for the higher end of the range (2.2 g/kg/day), that works out to about 0.55 g/kg per meal across four eating occasions. For a 180-pound person, that’s roughly 33 to 45 grams per meal.
What drives that per-meal minimum is an amino acid called leucine. It acts as a kind of ignition switch for muscle protein synthesis. You need roughly 2.5 to 3 grams of leucine in a sitting to flip that switch, which corresponds to about 25 to 30 grams of a complete protein source like eggs, dairy, meat, or fish. This becomes especially important for older adults, who need a stronger signal to kick-start the same process.
Animal Protein vs. Plant Protein
Animal proteins (meat, dairy, eggs, fish) are generally considered superior for muscle building because they contain all essential amino acids in high concentrations and are more digestible. A systematic review and meta-analysis of randomized controlled trials found that protein source didn’t significantly affect total lean mass or strength gains overall. However, animal protein did have a slight edge in percent lean mass, and the advantage was more pronounced in adults under 50, who gained an average of 0.41 kg more lean mass with animal protein compared to plant protein.
If you eat a plant-based diet, you can still build muscle effectively. The key is eating enough total protein and combining sources (grains with legumes, for instance) to cover all essential amino acids. Studies comparing whey and pea protein at similar doses (around 49 grams) found comparable results. You may just need a slightly higher total intake to compensate for the lower digestibility and leucine content of most plant proteins.
When You’re Cutting Body Fat
Protein needs actually go up, not down, when you’re in a calorie deficit. Your body is more likely to break down muscle tissue for energy when calories are restricted, and extra protein helps counteract that. The recommended range during a fat-loss phase is 1.6 to 2.2 g/kg/day, with most guidance leaning toward the higher end of that range.
For a 154-pound (70 kg) person cutting weight, that means 112 to 154 grams of protein daily. Spreading intake across meals of 20 to 30 grams each helps maintain a steady supply of amino acids and keeps the muscle-building machinery active even as you lose fat. This is one situation where hitting 2.0 g/kg or above makes a meaningful practical difference.
Adjustments for Adults Over 50
Aging muscles become less responsive to protein. This phenomenon, called anabolic resistance, means that the same 20-gram dose of protein that powerfully stimulates muscle building in a 25-year-old produces a blunted response in a 65-year-old. Older adults have lower rates of protein synthesis in response to both food and exercise.
An international expert panel recommends 1.0 to 1.2 g/kg/day as a general target for adults over 65, with higher intakes (1.2 g/kg/day or above) for those doing resistance training. Per-meal protein targets also shift upward: 25 to 30 grams per meal is recommended, corresponding to the 3 to 4 grams of leucine needed to overcome that reduced sensitivity. Randomized controlled trials confirm that combining protein at 1.0 to 1.3 g/kg/day with twice-weekly strength training significantly reduces age-related muscle loss and improves leg strength.
Is High Protein Safe for Your Kidneys?
This is one of the most persistent concerns around high-protein diets, and the evidence is reassuring for healthy people. A review from the National Institutes of Health concluded that concerns about high protein intake damaging healthy kidneys “appear to be ill advised” and that there is no reason to restrict protein in healthy individuals to protect kidney function.
The one legitimate concern is kidney stones. High animal protein intake increases uric acid excretion, which can raise the risk of uric acid stones over time. Staying well hydrated and eating plenty of fruits and vegetables helps offset this. If you already have kidney disease, protein intake is a different conversation, but for people with normal kidney function eating in the 1.6 to 2.2 g/kg range, the kidneys handle the extra load without issue.
Putting It All Together
The simplest approach: aim for 1.6 g/kg/day as your floor and 2.2 g/kg/day as your ceiling. Split your daily protein across at least four meals, targeting roughly 0.4 to 0.55 g/kg per meal. Prioritize protein sources that are rich in essential amino acids, whether that’s chicken, Greek yogurt, eggs, fish, or well-combined plant sources. If you’re over 50, push each meal toward 25 to 30 grams minimum. If you’re dieting, stay at the top of the range. And make sure you’re eating enough total calories and actually lifting, because protein without resistance training and adequate energy is just expensive fuel.