Understanding your protein result
The table summarizes the published intake ranges used by this calculator and where each comes from.
| Goal | Protein (g/kg/day) | Source of the range |
|---|---|---|
| General health (RDA) | 0.8 | Institute of Medicine Dietary Reference Intakes (2005) — minimum for nearly all healthy adults |
| Active lifestyle | 1.2 – 1.6 | Within the 1.2–2.0 g/kg athlete range of the AND/DC/ACSM joint position statement (2016) |
| Muscle gain | 1.6 – 2.2 | Morton et al. 2018 meta-analysis (~1.6 g/kg average plateau, upper CI ~2.2); consistent with ISSN 2017 guidance |
| Endurance training | 1.2 – 1.4 | Long-standing endurance reference range within the AND/DC/ACSM athlete recommendations |
- The RDA (0.8 g/kg) is a deficiency-prevention minimum for mostly sedentary adults, not an upper limit; intakes above it are common and generally safe in healthy people.
- For people with substantial excess body fat, calculating protein from total body weight can overestimate needs; some practitioners scale from an adjusted or lean body weight instead.
- Older adults may benefit from intakes above the RDA to counter age-related muscle loss; the PROT-AGE study group recommends 1.0–1.2 g/kg/day for healthy older adults.
- People with chronic kidney disease or other medical conditions should not increase protein intake without guidance from their healthcare team.
How much protein do you need per day?
Protein requirements depend on body weight, activity level and goals. The Recommended Dietary Allowance (RDA) — set by the U.S. Institute of Medicine in its 2005 Dietary Reference Intakes — is 0.8 grams of protein per kilogram of body weight per day for healthy adults. The RDA is defined as the intake sufficient to meet the needs of nearly all (97–98%) healthy, largely sedentary adults; it is a minimum to prevent deficiency, not an optimum for athletic goals.
Sports-nutrition research supports higher intakes for people who train. The International Society of Sports Nutrition's 2017 position stand recommends approximately 1.4–2.0 g/kg/day for building and maintaining muscle in exercising individuals, and a 2018 meta-analysis by Morton and colleagues found that benefits of protein for resistance-training muscle gain plateaued around 1.6 g/kg/day on average, with the upper confidence limit near 2.2 g/kg/day. The joint position of the Academy of Nutrition and Dietetics, Dietitians of Canada and the American College of Sports Medicine recommends 1.2–2.0 g/kg/day for athletes generally.
Distribution across the day also matters in sports-nutrition guidance: the ISSN suggests spreading protein evenly across meals, with roughly 0.25 g per kilogram of body weight (about 20–40 g) per meal every three to four hours to support muscle protein synthesis. Higher protein intakes within these ranges are generally considered safe for healthy adults, but people with kidney disease or other medical conditions should discuss protein targets with their healthcare team.
How to use this protein calculator
- Enter your body weight. Use the Metric/Imperial toggle to switch between kilograms and pounds.
- Select your goal: General health applies the 0.8 g/kg RDA; Active lifestyle uses 1.2–1.6 g/kg; Muscle gain uses 1.6–2.2 g/kg; Endurance training uses 1.2–1.4 g/kg.
- Read your daily protein range in grams per day — the lower and upper ends of the published range for your goal.
- Use the per-meal figure to spread the total across roughly four eating occasions, in line with sports-nutrition distribution guidance.
The formula behind protein needs
Daily protein is body weight in kilograms multiplied by a grams-per-kilogram factor for the chosen goal. The factors come from published sources: 0.8 g/kg is the Institute of Medicine RDA; 1.2–1.6 g/kg covers generally active adults within the athlete range recommended by the Academy of Nutrition and Dietetics / ACSM joint position (1.2–2.0 g/kg); 1.6–2.2 g/kg reflects the Morton 2018 meta-analysis breakpoint and its upper confidence limit for resistance-training muscle gain, consistent with ISSN guidance; and 1.2–1.4 g/kg is a long-standing reference range for endurance training at moderate volumes.
The per-meal figure divides the daily range by four, approximating the even-distribution pattern (protein every three to four hours) described in the ISSN position stand.
Common mistakes
- Confusing grams of protein with grams of protein-rich food — 100 g of cooked chicken breast contains roughly 30 g of protein, not 100 g.
- Treating the RDA of 0.8 g/kg as an optimal target for training goals; it is a minimum set to prevent deficiency in largely sedentary adults.
- Consuming most daily protein in one evening meal; distribution guidance favors spreading intake across three to five eating occasions.
- Calculating needs from a goal weight or from total weight at very high body-fat levels without professional input, which can meaningfully misstate the target.
- Assuming more is always better — evidence for muscle gain plateaus around 1.6–2.2 g/kg/day, and intakes far above that mainly displace other nutrients.
Perguntas frequentes
How much protein do I need to build muscle?
A 2018 meta-analysis in the British Journal of Sports Medicine (Morton et al.) found that protein's benefit for resistance-training muscle gain plateaued at about 1.6 g per kilogram of body weight per day on average, with an upper confidence limit near 2.2 g/kg. The International Society of Sports Nutrition recommends roughly 1.4–2.0 g/kg/day for building and maintaining muscle. For an 80 kg adult, 1.6–2.2 g/kg equals about 128–176 g of protein per day.
Is 0.8 g of protein per kilogram enough?
The 0.8 g/kg Recommended Dietary Allowance is the intake the Institute of Medicine judged sufficient to meet the needs of nearly all healthy, largely sedentary adults — it prevents deficiency. People who train regularly or are older adults are commonly advised higher intakes: sports-nutrition bodies recommend 1.2–2.0 g/kg for athletes, and the PROT-AGE group recommends 1.0–1.2 g/kg for healthy older adults.
Is a high-protein diet bad for your kidneys?
In healthy people, controlled studies have not shown that protein intakes within the ranges used by this calculator harm kidney function; the International Society of Sports Nutrition's position stand states that higher protein intakes are safe in healthy, exercising individuals. However, people with existing chronic kidney disease are often advised to limit protein, so anyone with kidney problems should follow their healthcare team's guidance.
How much protein can the body use per meal?
There is no hard cap at which extra protein is wasted, but muscle protein synthesis responds most efficiently to repeated moderate doses. The ISSN position stand suggests about 0.25 g of protein per kilogram of body weight per serving (roughly 20–40 g for most adults), spread every three to four hours, which is why this calculator shows a per-meal figure across four meals.
Do endurance athletes need more protein than the RDA?
Yes. Endurance training increases amino-acid oxidation and requires protein for repair of muscle tissue. The joint position of the Academy of Nutrition and Dietetics, Dietitians of Canada and the ACSM recommends 1.2–2.0 g/kg/day for athletes, with the lower half of that range (about 1.2–1.4 g/kg) a common reference for moderate-volume endurance training.
Should I calculate protein from current weight or goal weight?
Published recommendations are expressed per kilogram of actual body weight, and this calculator uses your entered current weight. For people with substantial excess body fat, per-kilogram formulas can overestimate needs because adipose tissue requires little protein; dietitians sometimes use an adjusted or lean body weight in that situation. A registered dietitian can personalize the target.
Referências
- Institute of Medicine. Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids. Washington, DC: The National Academies Press, 2005.
- Jäger R, Kerksick CM, Campbell BI, et al. International Society of Sports Nutrition Position Stand: protein and exercise. Journal of the International Society of Sports Nutrition 2017; 14: 20.
- Morton RW, Murphy KT, McKellar SR, et al. A systematic review, meta-analysis and meta-regression of the effect of protein supplementation on resistance training-induced gains in muscle mass and strength in healthy adults. British Journal of Sports Medicine 2018; 52(6): 376–384.
- Thomas DT, Erdman KA, Burke LM. Position of the Academy of Nutrition and Dietetics, Dietitians of Canada, and the American College of Sports Medicine: Nutrition and Athletic Performance. Medicine & Science in Sports & Exercise 2016; 48(3): 543–568.
- Bauer J, Biolo G, Cederholm T, et al. Evidence-based recommendations for optimal dietary protein intake in older people: a position paper from the PROT-AGE Study Group. Journal of the American Medical Directors Association 2013; 14(8): 542–559.