To gain muscle, most people need between 1.6 and 2.2 grams of protein per kilogram of body weight each day. For a 180-pound (82 kg) person, that works out to roughly 130 to 180 grams of protein daily. Below that range, you’re leaving muscle growth on the table. Above it, the extra protein doesn’t appear to help.
That range comes from a large meta-analysis published in the British Journal of Sports Medicine, which found that protein supplementation beyond 1.62 g/kg/day produced no further gains in fat-free mass during resistance training programs. But because individual responses vary, the researchers noted the upper confidence limit reached 2.2 g/kg/day, making that a reasonable ceiling if you want to cover your bases.
How to Find Your Number
Start by converting your body weight to kilograms (divide pounds by 2.2), then multiply by 1.6 on the low end and 2.2 on the high end. Here’s what that looks like at common body weights:
- 140 lbs (64 kg): 102–141 g protein per day
- 160 lbs (73 kg): 117–161 g protein per day
- 180 lbs (82 kg): 131–180 g protein per day
- 200 lbs (91 kg): 146–200 g protein per day
- 220 lbs (100 kg): 160–220 g protein per day
If you carry a significant amount of body fat, using your goal weight or lean body mass instead of total weight gives a more accurate target. A 250-pound person at 35% body fat doesn’t need 250 pounds’ worth of protein, because fat tissue doesn’t demand the same amino acid supply that muscle does.
Why Meal Distribution Matters
Hitting your daily total is the most important factor, but how you spread that protein across meals makes a measurable difference. A crossover study published in The Journal of Nutrition compared two groups eating identical amounts of total protein. One group distributed it evenly across three meals (roughly 30 grams each). The other group skewed it heavily toward dinner (about 11 grams at breakfast, 16 at lunch, and 63 at dinner). The even-distribution group had 25% higher muscle protein synthesis over 24 hours.
The practical takeaway: don’t save all your protein for one giant meal. Aim for at least 30 grams of high-quality protein at each of your three main meals. Research on meal frequency and lean mass found that consuming 30 to 45 grams per meal, spread across multiple meals, produced the strongest association with leg lean mass and strength. A serving of beef, chicken, or fish around the size of your palm typically delivers about 30 grams.
For older adults, the threshold per meal may be slightly higher. Studies suggest 30 to 40 grams per sitting is needed to maximally stimulate muscle protein synthesis in people over 50, since aging muscle becomes less responsive to smaller protein doses.
The Post-Workout Window Is Overrated
You’ve probably heard you need to slam a protein shake within 30 minutes of your last set. The evidence doesn’t support that urgency. When researchers controlled for total daily protein intake, the timing of protein around a workout had little additional effect on muscle growth. What matters far more is whether you’re consistently reaching your daily target and spreading it across meals.
That said, if you train fasted in the morning, eating protein relatively soon afterward makes sense simply because your body has gone many hours without it. And if your last meal was three or four hours before training, having protein within an hour or two after your session ensures your muscles have a fresh supply of amino acids during the recovery window. The point isn’t that timing is irrelevant. It’s that obsessing over a precise 30-minute cutoff misses the bigger picture.
Protein Needs During Fat Loss
If you’re trying to lose fat while keeping (or building) muscle, your protein needs actually go up, not down. When you eat fewer calories than you burn, your body becomes more willing to break down muscle for energy. Higher protein intake counteracts that.
Recommendations for athletes cutting weight range from 1.8 to 2.7 g/kg/day, depending on how aggressive the calorie deficit is and how lean you already are. For most people doing a moderate cut, 2.0 to 2.4 g/kg/day is a solid range. Beyond about 2.4 g/kg/day, additional protein is unlikely to provide further muscle-sparing benefits. So if you weigh 180 pounds and you’re in a calorie deficit, aiming for 165 to 195 grams per day is reasonable.
This is one reason high-protein diets feel easier during fat loss. Protein is the most satiating macronutrient, so eating more of it helps control hunger while protecting your hard-earned muscle.
Protein Quality and the Leucine Factor
Not all protein sources trigger muscle building equally. The key driver is leucine, one of the essential amino acids. Your muscles need a threshold dose of leucine at each meal to flip the switch on muscle protein synthesis. For younger adults, that threshold is roughly 2 to 2.5 grams of leucine per meal. For older adults, it’s closer to 3 grams.
Animal proteins (meat, fish, eggs, dairy) are naturally rich in leucine, so hitting the threshold is easy with a standard serving. A cup of Greek yogurt, two large eggs, or a chicken breast all get you there. Plant proteins tend to be lower in leucine gram for gram, which means you either need a larger portion or a combination of sources. Soy is the exception among plants, with a leucine content closer to animal protein. If you eat mostly plant-based, combining legumes with grains and eating slightly more total protein helps compensate for the lower leucine density.
Is High Protein Safe for Your Kidneys?
This concern comes up often and, for healthy people, the answer is reassuring. High-protein diets are not known to cause kidney problems in people with normal kidney function. The Mayo Clinic states this directly. The worry originated from clinical observations that high protein intake can worsen existing kidney disease, because damaged kidneys struggle to clear the byproducts of protein metabolism. But in healthy kidneys, the filtration system scales up without issue.
If you have kidney disease, diabetes, or other chronic conditions, your situation is different, and protein intake is worth discussing with your doctor. For everyone else eating in the 1.6 to 2.2 g/kg range, there’s no credible evidence of harm. Staying well hydrated is still a good idea, since your kidneys do process more waste products on a high-protein diet, but that’s basic maintenance rather than damage prevention.
Putting It All Together
The formula for muscle-building protein intake is simpler than the fitness industry makes it seem. Eat 1.6 to 2.2 grams per kilogram of body weight daily, split across at least three meals of 30 or more grams each. Prioritize protein sources rich in leucine. If you’re cutting calories, push toward the higher end of the range. If you’re eating at maintenance or in a surplus, the lower to middle end is sufficient.
Consistency over weeks and months matters far more than perfection on any given day. Missing your target by 20 grams occasionally won’t derail your progress. Chronically eating half of what you need will.