To build muscle, most people need 1.2 to 1.7 grams of protein per kilogram of body weight per day. For a 180-pound (82 kg) person, that works out to roughly 100 to 140 grams daily. A large meta-analysis published in the British Journal of Sports Medicine pinpointed the ceiling more precisely: muscle gains from resistance training plateaued at 1.6 grams per kilogram per day, with no additional benefit from going higher.
That number is a useful anchor, but your ideal intake depends on your age, whether you’re cutting weight, and where your protein comes from. Here’s how to dial it in.
The 1.6 g/kg Breakpoint
The most cited number comes from a 2018 meta-analysis that pooled 49 studies on protein supplementation and resistance training. Researchers found that adding protein to a lifting program reliably increased lean mass, but the returns stopped at a total daily intake of 1.62 grams per kilogram. Eating beyond that threshold didn’t produce further gains in fat-free mass.
For practical math, multiply your body weight in pounds by 0.73 to get grams per day at the 1.6 g/kg level. A 150-pound person lands around 110 grams. A 200-pound person lands around 145 grams. These numbers assume you’re consistently doing resistance training. Without a training stimulus, extra protein doesn’t magically become muscle.
How to Spread It Across Meals
Your body can only ramp up muscle-building so fast in response to a single meal. Studies show that muscle protein synthesis climbs as you eat more protein in one sitting, but the response tops out around 30 to 45 grams per meal. A classic study found that 30 grams of protein from beef maximally stimulated muscle protein synthesis, and doubling the portion didn’t increase the effect.
This means eating 130 grams of protein in two massive meals is less effective than splitting it across three or four. People who ate two or more meals containing 30 to 45 grams of protein had significantly more leg lean mass and strength than those who loaded their protein into a single meal. Aim for at least three protein-rich meals a day, each in that 30 to 45 gram window, rather than trying to cram it all into dinner.
Why the Target Rises After 50
As you age, your muscles become less responsive to protein. This is called anabolic resistance, and it means an older adult needs a bigger dose of protein to trigger the same muscle-building response a younger person gets. A 25-year-old might only need about 20 grams per meal to flip the switch. Someone over 50 needs closer to 30 to 35 grams per meal to get the same effect.
On a daily basis, adults over 65 who are active are generally advised to eat 1.2 to 2.0 grams per kilogram. Per meal, the recommendation is roughly 0.4 grams per kilogram of body weight, which for a 165-pound person translates to about 30 grams at each sitting. If you’re in this age group and lifting weights, staying at the higher end of that daily range gives you the best shot at maintaining and building lean mass.
Cutting Weight? You Need More, Not Less
When you eat fewer calories than you burn, your body doesn’t just pull energy from fat. It also breaks down muscle protein at a higher rate. Increasing your protein intake during a caloric deficit helps offset that loss. Research on athletes shows that protein needs during weight loss are 1.6 to 2.4 grams per kilogram per day, noticeably higher than during a standard muscle-building phase.
The combination of higher protein and continued resistance training is the most effective strategy for losing fat while holding onto muscle. If you’re dieting and trying to maintain your physique, push your intake toward the upper end of the range. A 170-pound person cutting weight should aim for 125 to 185 grams daily.
Plant-Based Protein Needs an Adjustment
Not all protein sources are equal when it comes to building muscle. The key driver is an amino acid called leucine, which acts as a trigger for muscle protein synthesis. You need roughly 2 to 3 grams of leucine in a meal to fully activate the process. Animal proteins like eggs, dairy, meat, and fish are naturally rich in leucine, so hitting that threshold is straightforward.
Plant proteins tend to be lower in leucine and sometimes lack one or more essential amino acids. To compensate, younger adults eating exclusively plant-based diets may need at least 20% more protein per meal, while older adults may need 30% more. In practical terms, a plant-based eater should target at least 30 grams of protein per meal (40 grams or more if over 50) and combine complementary sources like beans and rice or use plant-based protein isolates such as soy protein isolate to round out the amino acid profile.
A Pre-Sleep Dose Can Help
Your body repairs and remodels muscle tissue overnight, and giving it protein before bed provides the raw material for that process. Several studies have found that consuming about 30 grams of slow-digesting protein (like casein, the main protein in cottage cheese and casein shakes) before sleep measurably increases overnight muscle protein synthesis. Over the course of a 12-week training program, people who had a pre-sleep protein shake gained more muscle mass and strength than those who didn’t.
This isn’t a magic trick. It works primarily by adding another opportunity to hit that 30-gram-per-meal threshold, especially for people who struggle to fit enough protein into three daytime meals. If you’re already hitting your daily target across your regular meals, a bedtime snack is a bonus, not a necessity.
Is High Protein Safe?
For healthy people, high-protein diets in the ranges discussed here are not associated with kidney damage or other medical problems. The concern about protein harming kidneys applies specifically to people who already have kidney disease, because their kidneys struggle to clear the byproducts of protein metabolism. If you have existing kidney disease or diabetes, protein intake is something to discuss with your doctor. For everyone else, intakes up to 2.0 or even 2.4 grams per kilogram during a cut have been studied without adverse effects.
Putting It Together
Here’s a simplified framework based on your situation:
- General muscle building: 1.6 g/kg per day (about 0.73 g per pound), spread across 3 to 4 meals of 30 to 45 grams each.
- Over 50 and lifting: 1.2 to 2.0 g/kg per day, with at least 30 to 35 grams per meal.
- Losing weight while preserving muscle: 1.6 to 2.4 g/kg per day, with continued resistance training.
- Plant-based eaters: Add 20 to 30% more protein per meal compared to omnivores, and combine complementary protein sources.
Consistency matters more than precision. Hitting roughly 1.6 grams per kilogram every day, spread relatively evenly across meals, puts you at or near the ceiling for protein-driven muscle gains. Going slightly over won’t hurt, and falling slightly short on occasion won’t derail your progress. The bigger mistakes are eating too little total protein or cramming it all into one meal.