Most healthy adults need a minimum of 0.8 grams of protein per kilogram of body weight per day, which works out to about 0.36 grams per pound. For a sedentary 140-pound person, that’s roughly 50 grams. But that baseline number is just the floor, not the ceiling, and your actual needs shift significantly based on your age, activity level, and goals.
How to Calculate Your Baseline
The simplest formula: multiply your weight in pounds by 0.36. A 180-pound person lands at about 65 grams per day. A 140-pound person gets roughly 50 grams. This number, the Recommended Dietary Allowance (RDA), was established through nitrogen balance studies and represents the minimum needed to prevent deficiency in a sedentary adult. It’s not optimized for muscle building, athletic performance, or aging well. Think of it as the amount that keeps you from losing ground, not the amount that helps you gain it.
If you prefer metric, the calculation is even more straightforward: multiply your weight in kilograms by 0.8. A 70-kilogram adult needs at least 56 grams daily.
Higher Targets for Active People
If you exercise regularly, the RDA isn’t enough. The International Society of Sports Nutrition recommends 1.4 to 2.0 grams per kilogram of body weight per day for most exercising individuals looking to build or maintain muscle. For a 170-pound (77 kg) person, that range translates to roughly 108 to 154 grams daily, a significant jump from the 62-gram RDA minimum.
Where you fall within that range depends on what kind of training you do. Endurance athletes (runners, cyclists, swimmers) generally sit at the lower end. Resistance-trained individuals aiming to add muscle benefit from the higher end. There’s even evidence that intakes above 3.0 grams per kilogram per day can promote fat loss in experienced lifters, though that level of intake requires deliberate planning and isn’t necessary for most people.
For endurance exercise specifically, adding about 0.25 grams of protein per kilogram of body weight per hour of training, on top of your regular intake, helps reduce markers of muscle damage and post-exercise soreness.
Protein Needs After Age 65
Older adults need more protein than younger ones, not less. The PROT-AGE Study Group, an international panel focused on nutrition and aging, recommends at least 1.0 to 1.2 grams per kilogram per day for adults over 65. That’s 25 to 50 percent more than the standard RDA. The reason: aging muscles become less efficient at using dietary protein to repair and rebuild tissue, a phenomenon researchers call “anabolic resistance.”
Older adults who are physically active should aim for the higher end of that range, at or above 1.2 grams per kilogram. Those managing acute or chronic illnesses may need 1.2 to 1.5 grams per kilogram daily. Since muscle loss accelerates with age and contributes to falls, fractures, and loss of independence, getting enough protein is one of the most practical things older adults can do to protect their mobility.
How Much Protein Per Meal Matters
Your body can only use so much protein at once to build muscle. Acute studies suggest that roughly 25 to 30 grams of protein per meal is the threshold needed to maximally stimulate muscle repair in older adults. This corresponds to about 3 to 4 grams of leucine, the amino acid that acts as the primary trigger for muscle protein synthesis.
What this means in practice: spreading your protein across three or four meals tends to be more effective than eating most of it at dinner, which is what many people default to. A breakfast of toast and coffee with only 10 grams of protein is a missed opportunity. Adding eggs, Greek yogurt, or cottage cheese can bring that meal into the effective range.
Protein for Weight Loss
When you’re eating fewer calories than you burn, your body doesn’t just tap fat stores for energy. It also breaks down muscle. Higher protein intake during a caloric deficit helps preserve lean mass, which matters because muscle is metabolically active tissue that keeps your resting metabolism higher.
Research on postmenopausal women with obesity found that intakes of at least 1.0 gram per kilogram per day, and ideally around 1.2 grams per kilogram, are recommended to counteract diet-induced muscle loss. Protein also increases satiety more than carbohydrates or fat do, which makes it easier to stick with a reduced-calorie plan without constant hunger. If you weigh 160 pounds (73 kg) and you’re actively losing weight, aiming for 73 to 88 grams of protein daily is a reasonable target.
Not All Protein Sources Are Equal
Protein quality varies based on how well your body can digest it and how complete its amino acid profile is. Scientists measure this using a score called DIAAS (Digestible Indispensable Amino Acid Score), where higher numbers mean your body can use a greater proportion of the protein you eat.
Animal proteins generally score higher. Pork, eggs, and casein (the main protein in milk) all score above 100, meaning they deliver a complete and highly digestible amino acid profile. Soy scores 91 and whey comes in at 85, both classified as high-quality. Plant proteins tend to score lower: pea protein averages around 70, fava bean 55, and corn just 36.
This doesn’t mean plant-based diets can’t meet your protein needs. It does mean you may need to eat a bit more total protein or combine different plant sources to cover gaps in amino acids. Soy and potato protein are the standout plant options in terms of quality. Pairing grains with legumes (rice and beans, for example) is the classic strategy for complementing amino acid profiles.
Can You Eat Too Much Protein?
For people with healthy kidneys, high protein intakes in the range of 1.4 to 2.0 grams per kilogram appear to be safe. The concern arises with preexisting kidney issues. High dietary protein increases the filtering workload on your kidneys, a process called hyperfiltration. In people who already have mildly reduced kidney function, this extra load can accelerate decline. The Nurses’ Health Study, which followed women for 11 years, found that every additional 10 grams of daily protein was associated with a meaningful drop in kidney filtration rate among those who already had mild kidney impairment. No such effect was seen in women with normal kidney function.
People with a single kidney are generally advised to stay below 1.2 grams per kilogram per day. If you have no kidney disease and no risk factors for it, intakes up to 2.0 grams per kilogram are well within the range that research supports as safe. Above that level, the evidence is thinner and mostly limited to well-trained athletes under supervision.
Quick Reference by Goal
- Sedentary adult: 0.8 g/kg per day (about 0.36 g per pound)
- Active adult, general fitness: 1.2 to 1.6 g/kg per day
- Muscle building or intense training: 1.6 to 2.0 g/kg per day
- Weight loss while preserving muscle: 1.0 to 1.2 g/kg per day
- Adults over 65: 1.0 to 1.2 g/kg per day (up to 1.5 g/kg with chronic illness)
To put real numbers on this: a 150-pound (68 kg) person aiming for general fitness would target 82 to 109 grams per day. That’s roughly a chicken breast at lunch, a cup of Greek yogurt as a snack, and a palm-sized portion of fish or meat at dinner, with some additional protein from grains, beans, or dairy throughout the day.