Most adults need between 1.2 and 1.6 grams of protein per kilogram of body weight each day to maintain muscle mass. That’s roughly 82 to 109 grams daily for a 150-pound person. The official Recommended Dietary Allowance (RDA) is set lower, at 0.8 grams per kilogram, but that number reflects the minimum to avoid deficiency, not the amount that actually preserves lean tissue over time.
The RDA vs. What Your Muscles Actually Need
The RDA for protein is 0.8 grams per kilogram of body weight, which works out to about 0.36 grams per pound. For a 180-pound person, that’s roughly 65 grams a day. This figure was designed to prevent protein deficiency in the general population, not to optimize muscle retention. It’s a floor, not a target.
The International Society of Sports Nutrition recommends 1.4 to 2.0 grams per kilogram daily for exercising individuals who want to build or maintain muscle through a positive protein balance. If you weigh 160 pounds (about 73 kilograms), that translates to roughly 102 to 146 grams of protein per day. Where you fall in that range depends on how hard you train, your age, and whether you’re eating enough total calories.
Protein Needs by Activity Level
If you’re mostly sedentary but want to hold onto the muscle you have, aim for at least 1.0 to 1.2 grams per kilogram. This is meaningfully higher than the RDA and reflects what newer research consistently supports for preventing gradual muscle loss in otherwise healthy adults.
If you strength train regularly or do intense endurance exercise, your needs climb to the 1.4 to 2.0 gram per kilogram range. The more frequently and intensely you train, the closer to the upper end you should aim. Someone lifting weights four days a week has greater protein turnover than someone walking for 30 minutes a day, and their intake should reflect that.
Why Older Adults Need More
Aging muscles become less efficient at using dietary protein to repair and rebuild. This blunted response means older adults need a higher dose to get the same muscle-preserving effect a younger person gets from a smaller amount. Researchers now recommend that adults over 65 consume 1.0 to 1.2 grams per kilogram daily as a baseline, with some evidence supporting up to 1.6 grams per kilogram for those trying to maintain or increase muscle strength. For a 180-pound older adult, that’s anywhere from 82 to 130 grams a day.
This matters because age-related muscle loss, called sarcopenia, accelerates after 60 and contributes to falls, fractures, and loss of independence. Eating enough protein won’t stop aging, but it significantly slows the rate at which muscle disappears.
Protecting Muscle During Weight Loss
When you eat fewer calories than your body burns, you lose both fat and muscle unless you take deliberate steps to prevent it. Protein requirements jump significantly during a calorie deficit. Current recommendations for athletes losing weight sit at 1.6 to 2.4 grams per kilogram daily, and some research on resistance-trained individuals suggests needs as high as 2.7 grams per kilogram during aggressive dieting phases.
Going above about 2.4 grams per kilogram doesn’t appear to offer additional muscle-sparing benefits for most people. The practical takeaway: if you’re cutting calories to lose fat, increase your protein substantially and pair it with resistance training. This combination is the most reliable way to ensure most of what you lose comes from fat rather than lean tissue.
How to Spread Protein Across the Day
Your body can only use so much protein at once to stimulate muscle repair. Research shows that roughly 30 grams of protein in a single meal is enough to maximally trigger the rebuilding process, and eating more than that in one sitting doesn’t amplify the response much further. One study found that consuming about 30 grams of protein at each of three meals stimulated 24-hour muscle protein synthesis more effectively than eating the same total amount skewed toward dinner (the typical pattern of 10 grams at breakfast, 15 at lunch, and 65 at dinner).
The strongest association with leg muscle mass and strength appeared when people consumed one to two meals daily containing between 30 and 45 grams of protein. So if your target is 120 grams a day, splitting that into three or four meals of 30 to 40 grams each is more effective than loading most of it into a single large dinner. This is especially important for older adults, whose muscles require a higher protein dose per meal to flip the rebuilding switch.
Why Protein Source Quality Matters
Not all protein is created equal when it comes to maintaining muscle. What matters is how well your body can digest and use the amino acids in a given food, particularly one amino acid called leucine. Reaching about 2.5 to 3 grams of leucine per meal appears to be the threshold for fully activating muscle repair. Animal proteins like eggs, dairy, chicken, and fish hit this threshold easily in a typical serving. A chicken breast or a cup of Greek yogurt delivers both the total protein and the leucine your muscles need.
Plant-based proteins tend to have lower digestibility scores and less leucine per gram. When researchers account for protein quality in plant-heavy diets, what looks like adequate intake on paper can actually fall short. A diet providing 0.8 grams per kilogram from plant sources with roughly 70% digestibility effectively delivers only about 0.69 grams per kilogram of usable protein, which is below the minimum requirement. If you eat mostly or entirely plant-based, you’ll likely need to eat a higher total amount of protein and combine sources (legumes with grains, for example) to compensate for lower digestibility and amino acid profiles.
Practical Protein Targets by Body Weight
Here’s what the 1.2 to 1.6 grams per kilogram range looks like in practice for common body weights:
- 130 pounds (59 kg): 71 to 94 grams per day
- 150 pounds (68 kg): 82 to 109 grams per day
- 170 pounds (77 kg): 92 to 123 grams per day
- 200 pounds (91 kg): 109 to 146 grams per day
- 220 pounds (100 kg): 120 to 160 grams per day
If you strength train consistently, use the higher end. If you’re over 65, use the higher end. If you’re losing weight on purpose, go even higher, up to 2.0 to 2.4 grams per kilogram. If you’re a moderately active adult in your 30s or 40s, the middle of the range is a reasonable starting point. The one group that should be cautious with high protein intake is people with existing kidney disease, who may need to limit their intake based on medical guidance.