Most weightlifters need between 1.4 and 2.2 grams of protein per kilogram of body weight per day to maximize muscle growth. For a 180-pound (82 kg) person, that works out to roughly 115 to 180 grams daily. Where you fall in that range depends on whether you’re in a caloric surplus or deficit, how you spread protein across meals, and how hard you’re training.
The Daily Target Range
The International Society of Sports Nutrition recommends 1.4 to 2.0 g/kg/day for most people doing resistance training. A large meta-analysis looking at the dose-response relationship between protein and muscle gain found a clear inflection point at 1.3 g/kg/day. Below that threshold, every 0.1 g/kg increase in daily protein produced about 0.39 kg of additional lean mass. Above it, the same increase yielded only 0.12 kg. In other words, the first priority is clearing that 1.3 g/kg floor. Gains still happen above it, just at a slower rate.
For practical purposes, aiming for 1.6 g/kg/day is a reliable minimum target for muscle building. If you want a safety margin or you’re an experienced lifter pushing for every edge, going up to 2.2 g/kg/day is well supported. Beyond that, there’s little evidence of additional muscle-building benefit for most people.
Here’s what that looks like in real numbers:
- 150 lb (68 kg) lifter: 109–150 g protein per day
- 180 lb (82 kg) lifter: 131–180 g protein per day
- 220 lb (100 kg) lifter: 160–220 g protein per day
How to Split Protein Across Meals
Your body can only use so much protein at once for muscle repair. A single meal maxes out muscle protein synthesis at roughly 0.4 g/kg of body weight. For an 82 kg person, that’s about 33 grams per sitting. Eating 70 grams in one meal doesn’t double the muscle-building signal; it just sends more amino acids to be burned for energy or converted to other uses.
The most practical approach is to eat at least four protein-rich meals spaced about three to four hours apart, each containing 0.4 to 0.55 g/kg. Four meals at 0.4 g/kg hits the 1.6 g/kg daily minimum. Four meals at 0.55 g/kg reaches 2.2 g/kg, the upper end of the useful range. This even spacing keeps the muscle-building machinery running throughout the day rather than spiking it once and leaving it idle.
Protein Needs During a Cut
When you’re eating fewer calories than you burn, your protein needs go up, not down. A caloric deficit puts your body in a state where it’s more willing to break down muscle for energy, and higher protein intake counteracts that.
One striking study put young men on a steep 40% caloric deficit while they trained six days a week. The group eating 2.4 g/kg/day actually gained 1.2 kg of lean mass, while the group eating 1.2 g/kg/day barely maintained theirs. The ISSN suggests that resistance-trained individuals in a deficit may need 2.3 to 3.1 g/kg/day to maximize lean mass retention. At a bare minimum, staying above 1.2 g/kg/day while combining protein with resistance training helps spare muscle during weight loss.
The more aggressive your deficit, the more protein matters. If you’re doing a moderate cut of 500 calories per day, targeting the upper end of the standard range (around 2.0 g/kg) is a reasonable starting point. For steep cuts, pushing toward 2.4 g/kg or higher gives you a better chance of holding onto muscle.
The Post-Workout Window Is Wider Than You Think
The idea that you need to chug a protein shake within 30 minutes of your last set has been a gym staple for decades. The actual evidence is far less urgent. If you ate a protein-rich meal one to two hours before training, your body is still processing those amino acids during and after your workout. Rushing to consume more protein immediately afterward appears redundant in that scenario.
Where timing does matter: if you train fasted or it’s been more than three to four hours since your last meal, getting at least 25 grams of protein reasonably soon after training makes sense. The key guideline is that your pre- and post-workout meals shouldn’t be separated by more than roughly three to four hours, assuming a typical 45 to 90 minute session. Beyond that, your total daily intake and how evenly you distribute it matter far more than whether you eat at minute 15 or minute 90 post-workout.
Animal vs. Plant Protein
Animal proteins like meat, eggs, dairy, and fish are considered higher quality for muscle building because they contain more of the amino acid leucine, which acts as the primary trigger for muscle protein synthesis. A meal needs roughly 700 to 3,000 mg of leucine to flip that switch effectively, which corresponds to about 25 to 30 grams of animal protein.
A systematic review of randomized controlled trials found that animal and plant protein produced similar gains in total lean mass and muscle strength overall. However, animal protein did show an advantage in percentage lean mass, and the benefit was more pronounced in adults under 50. Younger lifters relying entirely on plant-based protein may need to eat slightly more total protein or be more deliberate about combining sources to match the leucine content of animal proteins. Soy, pea protein, and blends of legumes with grains can get you there, but the portion sizes tend to be larger.
Does High Protein Harm Your Kidneys?
This concern persists, but the evidence consistently shows that high protein intake does not damage healthy kidneys. An 11-year observational study of women found that higher protein was associated with declining kidney function only in those who already had mild kidney impairment. In women with normal kidney function, no such association existed. Randomized trials lasting over six months have generally shown little to no effect on kidney function in healthy people.
The one group that should be cautious is people with a single kidney, where intakes above 1.2 g/kg/day are typically discouraged. If you have existing kidney disease or a family history of it, that’s worth discussing with your doctor. For everyone else, intakes in the 1.6 to 2.2 g/kg range pose no demonstrated risk.
Older Lifters Don’t Necessarily Need More
Sedentary older adults develop something called anabolic resistance, where their muscles respond less efficiently to protein. This has led to recommendations that people over 65 eat more protein per meal (around 0.4 g/kg instead of 0.24 g/kg) to get the same muscle-building response as younger people. But lifters who have stayed active throughout their lives are a different population entirely. Research on master athletes, those over 50 who train consistently, shows they maintain muscle mass, body composition, and protein metabolism comparable to untrained people decades younger. The current evidence suggests that active older lifters can follow the same protein guidelines as younger ones, since their training habit effectively prevents the anabolic resistance that makes extra protein necessary for their sedentary peers.