To build muscle effectively, you need about 1.6 to 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. That range is where muscle protein synthesis, the process your body uses to repair and grow muscle fibers, is maximized. Going below that range leaves gains on the table, while going significantly above it doesn’t appear to offer additional benefits for most people.
Calculating Your Daily Target
The simplest approach is to convert 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:
- 150 lbs (68 kg): 109–150 g protein per day
- 175 lbs (80 kg): 128–176 g protein per day
- 200 lbs (91 kg): 146–200 g protein per day
- 225 lbs (102 kg): 163–224 g protein per day
Where you land within that range depends on a few factors. If you’re new to lifting, the lower end is likely sufficient since your body responds strongly to a new training stimulus. If you’re an experienced lifter pushing hard, aiming closer to 2.0 or 2.2 g/kg gives you a better margin. And if you’re dieting while trying to hold onto muscle, you’ll want to push even higher, which we’ll cover below.
How to Spread Protein Across the Day
Hitting your daily total matters most, but how you distribute it throughout the day can make a meaningful difference. The key mechanism is a specific amino acid called leucine, which acts as a trigger for muscle building at the cellular level. You need roughly 2 to 3 grams of leucine in a single sitting to flip that switch. In practical terms, that translates to about 20 to 40 grams of protein per meal, depending on the source.
Eating your entire daily protein in one or two massive meals is less effective than spreading it across three to five feedings. Each time you reach that leucine threshold, you get a fresh burst of muscle protein synthesis that lasts a few hours before tapering off. Spacing your meals 3 to 5 hours apart lets you trigger that process multiple times per day. A simple framework: aim for at least 0.4 to 0.5 g/kg of body weight per meal. For most people, that’s 30 to 40 grams at each of three or four meals.
Older adults generally need more protein per meal to get the same anabolic response. Research suggests people over 60 may need up to 40 grams per meal to effectively stimulate muscle growth, compared to the 20 to 25 grams that works well for younger adults.
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 significantly overstated. The so-called “anabolic window” was long thought to close within an hour after training, but evidence now suggests it extends to roughly 5 to 6 hours surrounding your workout, before and after combined.
In one study, groups that consumed protein before versus after resistance training saw similar changes in body composition and strength after 10 weeks. The practical takeaway: if you ate a meal containing protein within a couple of hours before training, there’s no urgency to eat again immediately after. Your pre-workout meal is already fueling recovery.
The one exception is fasted training. If you lift on an empty stomach, getting protein in soon after your session does become more important since your body has no recent amino acids to draw on. Otherwise, total daily intake matters far more than precise timing.
Animal vs. Plant Protein Sources
Not all protein sources are equally efficient at building muscle. Animal proteins, including meat, fish, eggs, and dairy, deliver a more complete set of essential amino acids and are more easily digested. They also tend to be naturally higher in leucine per gram of protein. Plant proteins can absolutely support muscle growth, but they come with some limitations: lower digestibility, and individual sources often lack one or more essential amino acids. Soy is missing adequate amounts of certain amino acids, while grains tend to be low in lysine.
If you eat a plant-based diet, the fix is straightforward. Combine different protein sources throughout the day (legumes with grains, for example) so the amino acid profiles complement each other, and aim for the higher end of the daily intake range, closer to 2.0 to 2.2 g/kg. That extra volume compensates for the lower digestibility and amino acid gaps in any single plant source.
Protein Needs During a Caloric Deficit
Cutting calories while trying to maintain or build muscle is a common scenario, and it changes the math. When you’re in a caloric deficit, your body is more likely to break down muscle tissue for energy, so protein requirements go up. Current recommendations for athletes dieting down sit at 1.8 to 2.7 g/kg per day, noticeably higher than the standard muscle-building range.
The more aggressive the cut, the more protein you need. Someone on a modest 300-calorie deficit can stay closer to 1.8 g/kg, while someone cutting hard for a competition or rapid fat loss may need to push toward 2.7 g/kg to preserve lean mass. This is one of the few situations where going above 2.2 g/kg has clear justification. High protein intake during a deficit also helps with satiety, making it easier to stick to reduced calories without constant hunger.
Is There an Upper Limit?
For healthy individuals, high-protein diets are not associated with kidney damage or other medical problems. This is one of the more persistent nutrition myths. Your kidneys are well-equipped to handle the byproducts of protein metabolism at the intakes discussed here, and even somewhat above them.
The caveat is pre-existing kidney disease. If your kidneys are already compromised, high protein intake can accelerate the decline in function because the organs struggle to clear the extra waste products. The same caution applies if you have diabetes or other chronic conditions that affect kidney health. But for someone with normal kidney function who’s training hard, eating 2.0 to 2.2 g/kg of protein daily poses no known health risks.
From a muscle-building standpoint, intakes above roughly 2.2 g/kg per day don’t appear to produce additional gains when you’re eating enough calories. Those extra grams simply get used for energy or other bodily functions. The exception, again, is during caloric restriction, where the higher range serves a protective role against muscle loss.
Putting It All Together
The core strategy is simpler than the fitness industry makes it sound. Calculate your daily target at 1.6 to 2.2 g/kg, split that across three to four meals of at least 20 to 40 grams each, and prioritize high-quality sources that deliver a full amino acid profile. If you’re plant-based, combine complementary sources and aim higher within the range. If you’re in a caloric deficit, push to 1.8 to 2.7 g/kg to protect muscle. Time your meals so you have protein within a few hours on either side of your training session, and don’t stress about the 30-minute window. Consistency in hitting your daily total will always outperform perfectly timed but inconsistent intake.