How Many Grams of Protein Do You Need a Day?

Protein is one of the three macronutrients (alongside carbohydrate and fat), built from amino acids, and obtained from food or supplements such as whey, casein, soy, or pea protein powder. This article covers dietary protein intake for healthy adults and common special populations. It does not cover protein needs in diagnosed protein-calorie malnutrition, dialysis, liver failure, or inherited metabolic disorders of amino acid metabolism, which require individualized management by a physician or renal dietitian.

Dietary protein requirements for healthy adults span a wide range depending on the question being asked: the RDA of 0.8 g/kg/day is a deficiency-prevention floor set by the National Academies, not an optimal target for muscle retention, athletic performance, or aging. Sports nutrition guidance points toward roughly 1.4 to 2.2 g/kg/day for people doing regular resistance training, and geriatric nutrition consensus groups have proposed 1.0 to 1.5 g/kg/day for adults over 65 to counter age-related anabolic resistance. No single number is "correct" for everyone; the right target depends on age, activity, kidney function, and whether the person is actively losing weight.

Where the 0.8 g/kg number comes from, and why it is a floor, not a target

The RDA of 0.8 g/kg/day for adults age 18 and older comes from the Institute of Medicine's Dietary Reference Intakes report, now maintained by the National Academies of Sciences, Engineering, and Medicine 1. It is defined as the amount that meets the needs of 97.5% of healthy sedentary adults, derived largely from older nitrogen-balance studies. It is not designed to represent an optimal intake for athletic performance, muscle retention with aging, or fat loss, and several protein researchers have argued nitrogen-balance methodology tends to underestimate true requirements. Readers should treat 0.8 g/kg as a deficiency-prevention floor rather than a wellness target.

For a 70 kg (154 lb) adult, 0.8 g/kg equals 56 g of protein per day; for a 57 kg (125 lb) adult, about 46 g. Both are achievable in two or three ordinary meals without supplementation.

The Institute of Medicine's Acceptable Macronutrient Distribution Range for protein is 10 to 35% of total daily calories 1. At 2,000 calories per day, that range spans roughly 50 to 175 g, which is wide enough to reflect how much individual need varies by goal and activity level.

The RDA does not adjust for obesity. Using actual body weight to set protein targets in someone with a high body-fat percentage can produce very high absolute gram targets, because adipose tissue has much lower protein turnover than lean tissue. Clinicians commonly use ideal or adjusted body weight instead in this situation; this is a matter of clinical judgment rather than a fixed rule, and any individual target should be set with a clinician or dietitian.

How much more do active adults and athletes need?

Sports nutrition position statements from bodies such as the International Society of Sports Nutrition have recommended roughly 1.4 to 2.0 g/kg/day for people who exercise regularly, with resistance-trained individuals often cited toward the upper end, around 1.6 to 2.2 g/kg/day. Systematic reviews of protein supplementation trials in resistance-trained adults have reported that muscle mass gains from added protein tend to plateau somewhere in the 1.6 g/kg/day range, with intakes above that showing little additional benefit for muscle growth, though also no clear evidence of harm to healthy kidneys. The precise plateau figure varies across analyses and should be treated as a general pattern rather than a fixed cutoff; a reader wanting the exact number from a specific meta-analysis should verify it against the published paper rather than relying on a single restated figure.

Endurance athletes oxidize some amino acids as fuel during long training sessions and are generally advised toward the lower end of the active-adult range, around 1.2 to 1.4 g/kg/day. A 70 kg endurance athlete at that range would target roughly 84 to 98 g/day.

Spreading protein across three to five meals, rather than concentrating it in one or two large meals, is commonly recommended in the sports nutrition literature as more effective for stimulating muscle protein synthesis over the course of a day. In practice this means aiming for roughly 25 to 40 g of protein at each main meal rather than saving most of it for dinner.

Do older adults need more protein, not less?

Muscle protein synthesis becomes less responsive to a given dose of dietary protein with age, a pattern researchers call anabolic resistance. Because of this, geriatric nutrition consensus groups, including the PROT-AGE Study Group, have recommended that healthy adults over 65 aim for roughly 1.0 to 1.2 g/kg/day, rising to about 1.2 to 1.5 g/kg/day for those managing acute or chronic illness. Sarcopenia (age-related loss of muscle mass and strength) is common in older adults and is linked to falls, fractures, and loss of independence, which is the practical reason these targets sit above the standard RDA rather than below it.

Protein source quality matters more with age. Leucine, one of the branched-chain amino acids, is a key trigger for muscle protein synthesis, and animal proteins (whey, eggs, poultry, beef, dairy) generally supply more leucine per gram than most plant proteins. Older adults eating primarily plant-based diets may need to aim toward the upper end of the 1.2 to 1.5 g/kg/day range, or combine complementary plant proteins, to compensate.

Because anabolic resistance blunts the response to small doses, some research suggests older adults may benefit from at least 30 to 35 g of protein per meal, somewhat more than the roughly 20 to 25 g that appears sufficient in younger adults. Three such meals covers 90 to 105 g per day for a 75 kg person, consistent with the 1.2 to 1.4 g/kg range.

Protein during weight loss, including GLP-1 receptor agonist therapy

During a calorie deficit, the body can break down muscle tissue for fuel if amino acid intake is too low, which is why higher protein intake is commonly recommended during weight loss. Clinical trial evidence in short-term calorie-restriction studies has generally found that protein intake around 1.6 g/kg/day, roughly double the RDA, preserves more lean body mass than RDA-level intake during a deficit, with some further preservation at still higher intakes. A commonly cited practical target for people actively losing weight is 1.2 to 1.6 g/kg of ideal body weight per day.

GLP-1 receptor agonists such as semaglutide (marketed as Wegovy and Ozempic) and tirzepatide (marketed as Zepbound and Mounjaro) are FDA-approved for chronic weight management or type 2 diabetes and produce substantial appetite suppression, which can cause total food and protein intake to drop lower than a patient realizes. A 2026 retrospective cohort study using the All of Us Research Program compared real-world weight loss across different GLP-1 receptor agonists in a large U.S. population 2; it is a useful anchor for the fact that real-world weight loss outcomes on these drugs are now being studied outside of controlled trials, though the exact comparative magnitudes reported should be verified against the published paper before being cited as a specific number. Separately, body-composition sub-analyses of GLP-1 weight-loss trials have raised concern that some portion of weight lost on these drugs is lean mass rather than fat mass, particularly when protein intake is low during treatment.

Reconciling conflicting protein targets: a decision framework

Most people fit more than one category above at once, and the categories do not always point in the same direction. Use this order of operations rather than averaging the numbers yourself:

1. Kidney function overrides everything else. If you have diagnosed chronic kidney disease, a single functioning kidney, or a history of kidney stones, protein targets should come from your nephrologist or renal dietitian, not from an age- or activity-based table. Restricted intakes (commonly cited around 0.6 to 0.8 g/kg/day for non-dialysis CKD) may apply, and self-directed high-protein eating could be harmful. Stop here and ask your clinician before applying any other row in this framework.
2. If kidney function is normal, start from your primary driver. Pick the single strongest driver of your protein need this month: active weight loss, resistance training, age 65+, pregnancy, or none of these (general maintenance).
3. If two drivers apply at once, use the higher number, not the sum. For example, an older adult who is also losing weight on a GLP-1 medication does not need "elderly protein" plus "GLP-1 protein" added together. Use the higher single-category target (commonly 1.2 to 1.5 g/kg/day in that combination) as a starting point, then reassess with a dietitian if weight loss stalls or muscle strength declines.
4. Set the target on ideal or adjusted body weight if you have a high body-fat percentage. Applying an athlete- or weight-loss-level multiplier to actual body weight in someone with obesity can generate an unrealistically high gram target. Ask a clinician to calculate this rather than estimating it yourself.
5. Reassess every 4 to 8 weeks based on function, not just the scale. Grip strength, recovery time, energy levels, and resistance to illness are more informative than a single body-weight number for deciding whether your current protein target is working.
6. Escalate to a clinician or dietitian if: you are losing strength or muscle mass despite eating what you believe is enough protein, you have unexplained leg or abdominal swelling, you have any kidney disease history, or you are pregnant and unsure how to adjust intake trimester by trimester.

Protein and appetite

Protein tends to be more satiating per calorie than carbohydrate or fat, an effect partly mediated by gut hormones such as peptide YY and endogenous GLP-1 released in response to protein intake. Controlled feeding studies have found that raising the protein share of the diet can meaningfully reduce spontaneous calorie intake without an explicit instruction to eat less, which is part of the rationale for higher-protein weight-loss diets independent of any specific medication.

Protein during pregnancy and lactation

Protein needs rise across pregnancy to support fetal growth, placental development, and expanded maternal blood volume. The Institute of Medicine's Dietary Reference Intakes recommend an additional roughly 25 g of protein per day above the sedentary-adult baseline during pregnancy, particularly from the second trimester onward 1. A 65 kg pregnant woman at the RDA baseline of about 52 g/day would therefore target roughly 77 g/day. Lactation needs remain elevated at a similar order of magnitude above baseline. Individual targets, especially for women with multiple pregnancies, low pre-pregnancy weight, or nutritional risk factors, should be set with an obstetric provider or registered dietitian rather than estimated from a general table.

Whole food sources, eggs, poultry, fish, legumes, and dairy, provide protein alongside folate, iron, and other nutrients important in pregnancy. Protein powders can help when nausea limits appetite but should not replace varied whole-food sources as the primary intake strategy.

How to estimate your own target

1. Convert body weight to kilograms (pounds divided by 2.2).
2. Choose the multiplier that best matches your situation from the table below.
3. Multiply weight in kilograms by the multiplier to get a daily gram target.

Everyday food reference points

A palm-sized serving of cooked chicken breast (about 85 g) supplies roughly 25 to 26 g of protein. Two large eggs provide about 12 g. A cup of cooked lentils provides roughly 18 g. A single scoop (about 30 g) of whey protein isolate typically provides 25 to 27 g. Combining one palm-sized portion of animal protein with a legume side at each of three meals brings most adults to roughly 80 to 100 g per day without formal tracking.

Protein quality: does the source matter?

Not all protein sources support muscle protein synthesis equally per gram. The Digestible Indispensable Amino Acid Score (DIAAS), developed through FAO expert consultation, is the current standard for measuring protein quality by comparing a food's digestible amino acid content to a reference pattern 3. Whey, eggs, milk, and meat generally score at or above 1.0, meaning they meet or exceed the reference pattern for all indispensable amino acids. Among plant proteins, soy comes closest to matching animal protein quality; most other plant proteins (pea, rice, wheat) score lower individually, though combining complementary plant sources across the day, such as rice with legumes, raises the overall amino acid profile. People eating primarily plant-based diets are commonly advised to aim somewhat higher in total protein, roughly 15 to 20% more, to compensate for lower per-gram anabolic efficiency; the exact percentage varies across studies and should be treated as an approximate adjustment rather than a precise rule.

Broader food-systems research is also examining how plant, animal, and novel protein sources can be diversified at a population level to meet nutrition needs sustainably, an active area of ongoing nutrition science rather than a settled clinical recommendation for individuals.

Protein supplements (whey, casein, pea, soy) are a convenient way to close a gap when food alone falls short. Sports nutrition guidance generally holds that once total protein intake meets recommended amounts, supplementation on top of an already adequate diet does not meaningfully add further muscle protein synthesis beyond what whole food already provides; this is a widely stated position in the sports nutrition literature rather than a single quotable study result, and readers should not treat any specific wording of it as a verbatim citation without checking the original position statement.

Is high protein intake safe for the kidneys?

The idea that high protein intake damages healthy kidneys is common in popular discussion but is not well supported by clinical evidence in people without pre-existing kidney disease. Small trials tracking resistance-trained adults consuming protein well above standard recommendations for up to a year have generally not found adverse changes in kidney function markers such as creatinine or estimated glomerular filtration rate. This evidence is reassuring for healthy adults but does not extend to people with reduced kidney function.

For people with diagnosed chronic kidney disease, guideline bodies including diabetes and kidney-disease organizations have recommended restricting protein intake, commonly cited in the range of 0.6 to 0.8 g/kg/day for non-dialysis CKD, to help slow disease progression. Anyone with CKD, a history of kidney stones, or a single functioning kidney should set a protein target only with nephrology or renal dietitian input, not from a general table like the one above.

Higher protein intake increases the kidneys' solute load and can raise urine concentration, so adequate hydration is a reasonable precaution for anyone eating a high-protein diet, even without direct evidence that it prevents a specific harm.

What under-eating protein looks like

Severe protein deficiency (kwashiorkor) is rare in high-income countries, but milder, unnoticed under-intake is more common, particularly in older adults, people eating primarily plant-based diets without planning, and people whose appetite is suppressed by illness or medication. Possible signs of inadequate protein intake include:

• Slower recovery after exercise or minor injury
• Gradual loss of muscle mass or grip strength over weeks to months
• More frequent minor illness
• Swelling in the legs or abdomen in more severe cases (this warrants prompt medical evaluation, not home management)
• Hair thinning or brittle nails
• Persistent hunger despite eating what seems like enough food

A registered dietitian can review a few days of typical eating and identify gaps without guesswork, and this is particularly worth doing for anyone on appetite-suppressing weight-loss medication, since reduced hunger can mask a slowly developing protein shortfall.

What is established, what is plausible, and what is not established

Established: the RDA of 0.8 g/kg/day is the deficiency-prevention floor for healthy sedentary adults, set by the National Academies. Higher protein intake (up to roughly 1.6 to 2.2 g/kg/day) is not associated with kidney harm in people with normal kidney function in the studies available. Protein distributed across multiple meals, and adequate total protein during a calorie deficit, are both associated with better lean-mass preservation than very low or very concentrated protein intake.

Plausible but not settled: the exact optimal upper bound for muscle gain (commonly cited near 1.6 g/kg/day) varies by study and population and should not be treated as a precise universal cutoff. The magnitude of lean-mass loss during GLP-1 therapy, and whether a specific protein target reliably prevents it, is still being studied; real-world cohort data on this question is newer than the original approval trials and worth tracking over time.

Not established: there is no validated protein target specific to GLP-1 receptor agonist use from a regulatory body or major guideline group as of this writing; the 1.2 g/kg figure used in this article is a reasonable clinical extrapolation, not an approved or guideline-endorsed number, and individual targets should be confirmed with a prescribing clinician. There is also no established Tolerable Upper Intake Level for protein in healthy adults, which means "how much is too much" cannot be answered with a single number for everyone.