To gain muscle, most people need between 1.2 and 1.6 grams of protein per kilogram of body weight per day. For a 180-pound (82 kg) person, that works out to roughly 100 to 130 grams daily. A large meta-analysis published in the British Journal of Sports Medicine found that protein intake beyond 1.6 g/kg/day produced no further muscle gains in people doing resistance training, making that a practical upper target for most lifters.
How to Calculate Your Target
The simplest approach is to multiply your body weight in kilograms by 1.2 to 1.6. If you think in pounds, divide your weight by 2.2 first, or just multiply your weight in pounds by 0.55 to 0.73. Here’s what that looks like at different body weights:
- 140 lbs (64 kg): 77–102 g protein per day
- 170 lbs (77 kg): 92–123 g protein per day
- 200 lbs (91 kg): 109–146 g protein per day
If you’re significantly overweight, base the calculation on your goal weight or lean body mass rather than your current weight. The 1.6 g/kg ceiling from the research assumes a relatively normal body composition. Mayo Clinic places the range for people who regularly lift weights at 1.2 to 1.7 g/kg/day, which aligns closely with the meta-analysis data.
Why More Isn’t Always Better
Eating 2 g/kg/day or more is common advice in bodybuilding circles, but the evidence doesn’t support it for most people. The meta-analysis that pooled data from 49 studies found a clear plateau at 1.6 g/kg/day. Beyond that threshold, extra protein didn’t translate into additional lean mass gains. Your body can still digest and use that protein for energy or other functions, but it won’t accelerate muscle growth.
Very high protein diets (above 2 g/kg/day) also come with trade-offs. Harvard Health notes that people eating very high protein diets have a higher risk of kidney stones. For healthy individuals without pre-existing kidney issues, moderate overages aren’t dangerous, but there’s no muscle-building reason to push that high.
How Much Protein Per Meal
Your body doesn’t stop building muscle after 20 or 30 grams in one sitting, despite what older advice suggested. Recent research shows that 20 grams of protein per meal strongly stimulates muscle repair over about four hours, but eating 40 grams or more boosts that response by an additional 10 to 20 percent. When meals are spaced further apart (five hours or more), a larger serving of 40-plus grams helps sustain muscle building over that longer gap.
The old idea that your body “wastes” protein above a certain per-meal threshold doesn’t hold up. Researchers have found that the muscle-building response to protein has no strict upper limit in healthy adults. That said, spreading your intake across three or four meals is a practical way to hit your daily target without relying on one or two massive servings. Think 30 to 40 grams per meal if you eat three meals a day and your target is around 100 to 120 grams total.
The Post-Workout Window Is Overrated
The idea that you need to chug a protein shake within 30 to 60 minutes of your last set has been a gym staple for decades. The evidence doesn’t support it. Studies comparing protein consumed immediately after exercise to protein consumed at other times of day found no measurable difference in muscle or strength gains, as long as total daily protein intake was adequate and spread reasonably across meals.
What matters far more is hitting your daily protein target consistently. If you train at 7 a.m. and your next meal isn’t until noon, having a shake after your workout is practical. But if you ate an hour before training and plan to eat again within a couple of hours, there’s no urgency. A wide range of eating patterns can optimize muscle growth when daily protein is at or above 1.6 g/kg.
Protein Needs Change With Age
Older adults need more protein per meal to get the same muscle-building signal that younger people get from a smaller dose. This is called anabolic resistance: your muscles become less responsive to protein as you age, so you need a larger stimulus to trigger the same repair process. Stanford Lifestyle Medicine describes it simply: you need to “speak louder” for your muscles to hear.
In practical terms, young adults in their twenties can stimulate strong muscle repair with about 20 grams of protein per meal (roughly 0.2 g/kg of body weight). Adults over 50 typically need closer to 30 to 35 grams per meal, and adults over 70 may need 40 grams per meal (about 0.4 g/kg per meal) to get the same response. Daily totals for adults over 50 should be 1.2 to 1.6 g/kg/day at minimum, with some guidelines for those over 65 going as high as 2.0 g/kg/day.
Plant Protein Works, With One Caveat
A systematic review and meta-analysis comparing plant-based and animal-based protein supplements found no significant differences in lean body mass, muscle strength, or physical performance between the two groups. Soy protein, the most commonly studied plant source, performed comparably to whey across multiple trials.
The caveat is that plant proteins tend to be lower in certain amino acids that drive muscle repair. One amino acid in particular, leucine, acts as a trigger for muscle protein synthesis. You need roughly 2.5 to 3 grams of leucine per meal to flip that switch, and most animal proteins deliver that in a standard serving. Plant sources like beans, lentils, or tofu require a larger portion or a mix of sources to reach the same leucine content. But if total daily protein is adequate and you’re eating a variety of plant foods, the end result for muscle growth is comparable.
Putting It All Together
The practical blueprint is straightforward. Aim for 1.2 to 1.6 grams of protein per kilogram of body weight daily, distributed across three to four meals of roughly 25 to 40 grams each. If you’re over 50, push toward the higher end of both the daily and per-meal ranges. Prioritize total intake over timing, eat a mix of protein sources you actually enjoy, and pair your nutrition with consistent resistance training. Protein alone doesn’t build muscle. It provides the raw material, and training provides the signal telling your body to use it.