Most healthy adults need at least 0.8 grams of protein per kilogram of body weight per day to maintain muscle mass. That’s roughly 55 grams for a 150-pound person or 73 grams for someone weighing 200 pounds. But that baseline shifts significantly depending on your age, activity level, and whether you’re eating in a caloric deficit.
The Baseline for Sedentary Adults
The standard recommendation across the U.S., Canada, and Europe is 0.8 to 0.83 grams of protein per kilogram of body weight per day. This number was established to maintain nitrogen balance, meaning your body breaks down and rebuilds protein at roughly equal rates, in about 98% of adults. It applies regardless of sex.
To convert your weight: divide your weight in pounds by 2.2 to get kilograms, then multiply by 0.8. A 170-pound person weighs about 77 kilograms and would need around 62 grams of protein daily at this baseline. That’s achievable with something like two chicken breasts or a combination of eggs, yogurt, and a serving of fish throughout the day.
This number works for people who aren’t exercising regularly and aren’t trying to lose weight. If either of those applies to you, your needs are higher.
How Exercise Changes the Number
If you lift weights, run, cycle, or do any regular structured exercise, the International Society of Sports Nutrition recommends 1.4 to 2.0 grams per kilogram per day for both building and maintaining muscle. For that same 170-pound person, that range works out to roughly 108 to 154 grams daily.
A meta-analysis of resistance-trained individuals found that total daily protein intake of about 1.6 g/kg per day is sufficient to maximize muscle gains in people eating at or above their calorie needs. The upper confidence interval in that analysis reached 2.2 g/kg per day, but most people will see full benefits well below that ceiling. If your goal is simply to hold onto the muscle you already have rather than build more, aiming for the lower end of the range (1.4 to 1.6 g/kg) is a reasonable target.
Protein Needs During Weight Loss
Cutting calories while trying to keep your muscle is one of the hardest nutritional balancing acts, and it demands more protein than maintenance at a stable weight. When you’re in a caloric deficit, your body is more inclined to break down muscle tissue for energy unless protein intake is high enough to offset that loss.
Recommendations for athletes losing weight range from 1.6 to 2.4 grams per kilogram per day. Resistance-trained individuals may need even more, with some research suggesting up to 2.7 g/kg. However, intakes above about 2.4 g/kg are unlikely to provide additional muscle-sparing benefit. For a 170-pound person cutting calories, that means aiming for roughly 124 to 185 grams of protein per day. The more aggressive your calorie deficit and the leaner you already are, the closer to the upper end you should aim.
Why Older Adults Need More
Aging muscles become less responsive to protein. The same meal that triggers robust muscle repair in a 30-year-old produces a weaker response in a 65-year-old, a phenomenon researchers call “anabolic resistance.” This is one reason age-related muscle loss (sarcopenia) is so common.
Research using precise amino acid tracking found that older adults already experiencing muscle loss need about 1.2 g/kg per day on average, with a recommended intake of roughly 1.5 g/kg per day. That’s nearly double the standard 0.8 g/kg guideline. Even older adults without sarcopenia appear to need around 1.4 g/kg per day based on fat-free mass calculations. If you’re over 65 and want to preserve your strength and independence, treating the standard recommendation as a floor rather than a target makes sense.
How to Spread Protein Across Meals
Your body doesn’t store excess protein the way it stores carbohydrates or fat. Eating 120 grams at dinner and almost none at breakfast is less effective than distributing your intake more evenly. Research suggests aiming for about 0.4 grams per kilogram per meal across at least four meals to reach a daily minimum of 1.6 g/kg. For a 170-pound person, that works out to roughly 30 to 40 grams per meal.
This per-meal target aligns with the amount needed to fully activate muscle protein synthesis. In younger adults, that activation peaks at about 20 to 25 grams of high-quality protein per sitting. Older adults need more per meal to get the same response, with some research placing the threshold at 25 to 30 grams. The key amino acid driving this process is leucine, and roughly 3 to 4 grams of it per meal appears necessary for older adults to reach full muscle-building activation. You’ll hit that amount in about 25 to 30 grams of most animal proteins or a somewhat larger serving of plant-based options.
Plant Protein vs. Animal Protein
Animal proteins like meat, fish, eggs, and dairy contain all the essential amino acids in sufficient quantities and are easily digested. Plant proteins tend to be lower in one or more essential amino acids and are generally less digestible, which can reduce their muscle-building potential gram for gram.
That said, the practical differences are smaller than you might expect. A systematic review of randomized controlled trials found no statistically significant difference in total lean mass or muscle strength between people eating animal versus plant protein. Animal protein did produce a small but meaningful advantage in percent lean mass (the proportion of your body that’s muscle rather than fat). In adults under 50, animal protein was associated with about 0.41 kilograms more lean mass than plant protein.
If you eat mostly or entirely plant-based, you can close this gap by eating a higher total amount of protein, combining different plant sources to cover all essential amino acids, and favoring higher-leucine options like soy, peanuts, and lentils. You don’t need animal products to maintain muscle, but you do need to be more deliberate about your protein choices.
Practical Protein Targets by Body Weight
- 130 lbs (59 kg): 47 g/day at the baseline, 83–118 g/day if active
- 150 lbs (68 kg): 54 g/day at the baseline, 95–136 g/day if active
- 170 lbs (77 kg): 62 g/day at the baseline, 108–154 g/day if active
- 200 lbs (91 kg): 73 g/day at the baseline, 127–182 g/day if active
- 220 lbs (100 kg): 80 g/day at the baseline, 140–200 g/day if active
If you’re over 65, use the active range (1.4–2.0 g/kg) even if you exercise only moderately. If you’re losing weight intentionally, use 1.6–2.4 g/kg regardless of age. And if you’re both older and dieting, protein should be the last macronutrient you cut.