The European Food Safety Authority (EFSA) sets a population reference intake of 0.83 grams of protein per kilogram of body weight a day for adults. That figure is a planning benchmark for generally healthy people, not a universal target for athletes, older adults with higher needs, or people with kidney disease.

Protein grams are not the same as the weight of a food. A 100-gram serving of fish, tofu or beans contains water, fat, carbohydrate and other nutrients, so its protein content must come from the food label or a reliable national food-composition database.

When symptoms need urgent care

A major drop in urine output, persistent vomiting, swelling of the feet or legs, new confusion, unusual sleepiness or breathlessness needs prompt medical assessment. The United Kingdom's National Health Service lists these as possible symptoms of acute kidney injury and advises people who suspect it to seek urgent medical help. A protein calculation cannot determine the cause of these symptoms.

People with known kidney or liver disease, diabetes, frailty, recent major illness, poor appetite or a history of an eating disorder should not start a high-protein or protein-restricted diet without clinical advice. Children, pregnant or breastfeeding people, and anyone taking prescription medicines also need guidance matched to growth, pregnancy, lactation, illness and treatment.

Raw chicken breast with garlic and spices on a cutting board (illustrative image)

Start with the reference that fits the population

EFSA's dietary reference tables set the adult population reference intake at 0.83 grams per kilogram a day. Multiplying body weight in kilograms by 0.83 gives an estimate: 60 kilograms produces 49.8 grams a day, while 75 kilograms produces 62.25 grams.

This is a reference intake designed to cover the needs of nearly all healthy people in a population. It is not a minimum below which deficiency begins, and a single day's intake does not establish nutritional status. National authorities may use different terminology or values, so a locally published standard takes precedence when available.

The same EFSA opinion assigns separate age-based values to infants, children and adolescents, and extra daily amounts during pregnancy and breastfeeding. Those groups should not use the adult multiplication alone. Growth, gestational stage, total energy intake and clinical conditions all affect the calculation.

Most healthy adults can obtain protein from ordinary food

The World Health Organization says protein providing 10 to 15 percent of daily energy is generally sufficient for adults, or about 50 to 75 grams in a 2,000-calorie diet. It says protein can come from a mix of plant and animal sources and places that advice within a diet that also supplies vegetables, fruit, pulses, whole grains and appropriate fats.

Useful sources include beans, lentils, chickpeas, soy foods, nuts, seeds, eggs, dairy foods, fish, poultry and meat. The amount in a serving varies by food and preparation. Checking the protein line on a package or a national food database is more accurate than treating every egg, glass of milk or piece of tofu as interchangeable.

Adding a powder or bar is not required merely because a daily target has been calculated. Supplements can add calories or displace foods that provide fiber and micronutrients. Product composition, labeling and availability also vary by country.

Regular training raises the range

The International Society of Sports Nutrition (ISSN) says 1.4 to 2.0 grams per kilogram a day is sufficient for building and maintaining muscle in most exercising people. For an 80-kilogram adult, that range is 112 to 160 grams a day.

The position statement says the appropriate point within the range depends on training volume, age, body composition, total energy intake and training status. It also discusses higher intakes during an energy deficit in resistance-trained people, but that narrower use should not be presented as a target for anyone seeking weight loss.

ISSN reports that general per-meal recommendations for athletes are about 0.25 grams per kilogram, or 20 to 40 grams of high-quality protein, with feedings spread through the day. This is an exercise-nutrition framework, not evidence that every healthy adult needs a fixed protein dose at each meal.

A barbell and a container of protein drink in a gym (illustrative image)

Older adults have a separate evidence base

The PROT-AGE Study Group recommends 1.0 to 1.2 grams per kilogram a day for healthy adults older than 65. The group advises at least 1.2 grams per kilogram for older people who exercise and 1.2 to 1.5 grams for many with acute or chronic illness.

Those upper ranges do not apply automatically when kidney function is impaired. Poor appetite, unintended weight loss, frailty and sarcopenia can also make an aggressive restriction harmful if it reduces energy intake. An older person with any of these factors needs assessment of the whole diet and health status, not a protein number in isolation.

Steamed egg, fish and soft tofu served as an easy-to-eat meal (illustrative image)

Chronic kidney disease changes the calculation

Kidney Disease: Improving Global Outcomes (KDIGO) suggests 0.8 grams per kilogram a day for adults with stage G3 to G5 chronic kidney disease and advises those at risk of progression to avoid intake above 1.3 grams per kilogram. The 2024 guideline calls for a renal dietitian or other accredited nutrition professional to tailor protein, sodium, phosphorus and potassium advice to disease severity and other conditions.

KDIGO allows a very-low-protein diet only for selected adults at risk of kidney failure who are willing and able to follow it under close supervision, with specified amino-acid or ketoacid supplementation. It says not to prescribe low or very-low-protein diets to metabolically unstable people and not to restrict protein in children with chronic kidney disease because of the risk to growth.

Dialysis changes nutrient losses and treatment goals, so the nondialysis G3 to G5 figure cannot be carried over. A dialysis team should set the target. The same caution applies when kidney disease coexists with diabetes, frailty, sarcopenia or undernutrition.

Higher intake has not been proved safe for a lifetime

A 2018 systematic review and meta-analysis of 28 articles involving 1,358 adults found no difference in changes in glomerular filtration rate between higher- and lower- or normal-protein diets in people without kidney disease. Higher-protein diets in the review provided at least 1.5 grams per kilogram, at least 100 grams a day or at least 20 percent of energy.

The finding does not establish that a particular high intake is harmless for decades. Trials were generally short, definitions of a high-protein diet varied, and another systematic review cited by the authors rated much of the available evidence at moderate to high risk of bias. Evidence from healthy trial participants also cannot be transferred to people with diagnosed or unrecognized kidney impairment.

A defensible reading is narrower than the claim that protein either inevitably damages healthy kidneys or can be increased without limit. Healthy adults in the analyzed trials did not show worse filtration changes, while KDIGO separately advises limits for chronic kidney disease. Anyone considering a sustained intake far above a general or sports reference should first establish whether a medical condition changes the risk.

How to calculate and check a daily total

First select a reference for the correct group, then multiply the stated grams per kilogram by body weight in kilograms. Add the protein listed for each food and drink across the day. Keep the unrounded calculation for planning, but treat the result as an estimate because serving size and food composition vary.

A calculation should be checked against the rest of the diet. Meeting a protein number while crowding out vegetables, fruit, whole grains or adequate energy does not meet the WHO description of a diverse, balanced diet. Plant and animal foods can both contribute, and the appropriate mix depends on local food access, culture, nutrient needs and medical constraints.

Frequently asked questions

How much protein does a healthy adult need?
EFSA's population reference is 0.83 grams per kilogram a day. A 60-kilogram adult would calculate about 50 grams, but national standards and individual circumstances can differ.

Does an athlete need more?
ISSN places most exercising people at 1.4 to 2.0 grams per kilogram a day. The suitable point depends on the sport, training load, total energy intake, age and goals.

Should older adults use the general adult figure?
Not always. PROT-AGE recommends 1.0 to 1.2 grams per kilogram for healthy adults older than 65, with higher ranges for some active or ill older people. Kidney disease, frailty and undernutrition require an individualized assessment.

Do high-protein diets damage healthy kidneys?
The cited 2018 meta-analysis did not find worse changes in filtration among healthy adults eating higher-protein diets, but the evidence was not long enough to prove lifetime safety. People with chronic kidney disease have different targets.

Can someone with chronic kidney disease use an online formula?
Not as a stand-alone plan. KDIGO's 0.8-gram figure applies to adults with G3 to G5 chronic kidney disease who are not covered by reasons for a different target, and the guideline calls for advice tailored to disease severity and other conditions.