Protein Intake Calculator

Background.

Ask how much protein a 70 kg adult who lifts weights a few times a week should eat, and you can get three very different answers. The US Recommended Dietary Allowance of 0.8 g per kilogram says 56 g. The International Society of Sports Nutrition's range for exercising adults, 1.4 to 2.0 g/kg, says 98 to 140 g. And the gym rule of one gram per pound says about 154 g. None of these is a mistake; they answer different questions, and the useful one for you depends on how much you move and what you are trying to change.

This calculator settles on a band for your situation. You choose one of five activity levels, from sedentary to competitive athlete, and one of four goals — maintenance, muscle gain, fat loss or endurance — and that pair selects a range in grams per kilogram of body weight. The midpoint of the range, multiplied by your weight, is the daily target; the two ends give the low and high days around it. Across the twenty combinations the rate runs from 0.8 g/kg for a sedentary adult keeping things steady up to 2.4 g/kg at the top of the athlete fat-loss and muscle-gain bands.

The ordering follows the evidence summarised in the position stands cited below. More training means more protein. Muscle gain asks for the most at any activity level. Fat loss sits above maintenance, because eating less energy makes muscle harder to hold on to, and in Longland and colleagues' 2016 randomized trial, people on a higher-protein diet during a deficit with hard training gained more lean mass and lost more fat than those eating less protein. Endurance training falls in between.

The figures are meant for healthy adults and count protein from every source. They are not designed for children, pregnancy or breastfeeding, and anyone with kidney or liver disease should take their protein target from their own clinician or a dietitian rather than from a sports-nutrition table.

What is protein intake calculator?

Dietary protein is the food source of amino acids, the building blocks the body uses for muscle, enzymes, antibodies, hormones and connective tissue. Nine of them — histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan and valine — are essential, meaning they must come from food. Body proteins are broken down and rebuilt continuously, so a steady daily intake is needed to replace what is lost. The RDA of 0.8 g/kg, set by the Institute of Medicine in 2005 from nitrogen-balance studies, is the intake that meets the needs of nearly all healthy adults, around 97 to 98 percent of them, at ordinary activity. Sports-nutrition guidance is a different kind of figure: an intake intended to support training, muscle repair and lean-mass retention, which is why it sits higher. Unlike fat and carbohydrate, protein has no dedicated storage depot in the body; amino acids eaten beyond what is needed for building and repair are burned for energy or converted, which is why intake is spread through the day rather than banked.

How to use this calculator.

1. 01Enter your current body weight and pick kilograms or pounds. Pounds are converted at the exact 0.45359237 kg per lb, and the field accepts 1–500 kg or 2.2–1,110 lb.
2. 02Choose the activity level that describes a typical week, not your best one. A desk job with occasional walks is sedentary; a physical job or regular workouts most days is moderate; daily hard training or heavy manual work is active; the athlete level is for competitive training, often twice a day.
3. 03Choose the goal for your current phase. If you are eating less to lose weight, pick fat loss even if you also hope to gain muscle, because the deficit is what raises the protein need.
4. 04Read the daily target together with its lower and upper bounds. Landing anywhere in that band on a given day is consistent with the guidance behind it; the midpoint is simply a convenient number to plan around.
5. 05Count protein from everything you eat, using the grams printed on nutrition labels, and spread the total over three to five meals rather than loading it into dinner.

The formula.

The calculation is a lookup followed by a multiplication: P = r × W, where W is body weight in kilograms (pounds × 0.45359237) and r is the midpoint of the g/kg range for your activity level and goal. For maintenance the ranges climb in steps of 0.2 g/kg from 0.8–1.0 (sedentary) through 1.0–1.2 (light), 1.2–1.4 (moderate) and 1.4–1.6 (active) to 1.6–1.8 (athlete). Endurance adds 0.2 g/kg to each of those, fat loss adds 0.4, and muscle gain adds 0.6, so sedentary muscle gain is 1.4–1.6 and athlete muscle gain 2.2–2.4. Two fat-loss bands are wider than the rest: active fat loss runs 1.8–2.2 and athlete fat loss 2.0–2.4. The lower and upper outputs are the ends of the band times your weight. Your choice of setting moves the answer far more than a few kilograms do: for the same 70 kg person, sedentary maintenance gives 0.9 × 70 = 63 g while athlete muscle gain gives 2.3 × 70 = 161 g, about 2.56 times as much, whereas a 5% error in body weight changes either figure by only 5%. The per-pound rate is r × 0.4536, and the energy figure is P × 4 kcal, the Atwater factor for protein. The grid is a synthesis rather than a table printed in any one paper: its ends are anchored to the IOM's 0.8 g/kg RDA and to the ranges in the ACSM (1.2–2.0 g/kg for athletes) and ISSN (1.4–2.0 g/kg for exercising adults) statements, and the cells between interpolate. Two limits follow from the design. The rate is applied to total body weight, so a person carrying a lot of body fat gets a larger figure than their muscle mass calls for. And the highest rate is 2.4 g/kg, below the 2.3–3.1 g/kg of fat-free mass that Helms and colleagues suggested for lean athletes in an aggressive cut.

A worked example.

Frequently asked questions.

References& sources.

1. [1]Jäger R, Kerksick CM, Campbell BI, Cribb PJ, Wells SD, Skwiat TM, et al. — International Society of Sports Nutrition Position Stand: Protein and Exercise. Journal of the International Society of Sports Nutrition 2017;14:20. The primary source for the 1.4–2.0 g/kg/day range for exercising adults, and the up-to-3.1 g/kg figure for lean-mass preservation in deficit.
2. [2]Thomas DT, Erdman KA, Burke LM — American College of Sports Medicine, Academy of Nutrition and Dietetics, and Dietitians of Canada Joint Position Statement: Nutrition and Athletic Performance. Medicine & Science in Sports & Exercise 2016;48(3):543–568. The cross-society consensus citing 1.2–2.0 g/kg/day for athletes and the IOM 0.8 g/kg RDA floor for sedentary adults.
3. [3]Institute of Medicine (US) Panel on Macronutrients — Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids (Macronutrients). Washington (DC): National Academies Press, 2005. The U.S. authoritative source for the 0.8 g/kg/day RDA, the 10–35% AMDR for protein energy, and the underlying nitrogen-balance methodology.
4. [4]Bauer J, Biolo G, Cederholm T, Cesari M, Cruz-Jentoft AJ, Morley JE, 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. The primary recommendation for 1.0–1.2 g/kg/day in healthy older adults and 1.2–1.5 g/kg/day in the context of acute or chronic illness, with the anabolic-resistance rationale.
5. [5]Atwater WO, Benedict FG — Experiments on the Metabolism of Matter and Energy in the Human Body. United States Department of Agriculture, Office of Experiment Stations, Bulletin No. 69. Washington (DC): Government Printing Office, 1902. The original derivation of the 4 kcal/g energy factor for dietary protein still embedded in modern nutrition-facts accounting.
6. [6]Helms ER, Aragon AA, Fitschen PJ — Evidence-Based Recommendations for Natural Bodybuilding Contest Preparation: Nutrition and Supplementation. Journal of the International Society of Sports Nutrition 2014;11:20. The source for 2.3–3.1 g/kg of fat-free mass during aggressive deficits to preserve lean mass in lean athletes.
7. [7]Phillips SM, Van Loon LJC — Dietary Protein for Athletes: From Requirements to Optimum Adaptation. Journal of Sports Sciences 2011;29 Suppl 1:S29–S38. The reference for the per-meal leucine threshold (~2.5–3 g) and the 20–40 g per-meal dose required to maximally stimulate muscle protein synthesis.
8. [8]Longland TM, Oikawa SY, Mitchell CJ, Devries MC, Phillips SM — Higher Compared with Lower Dietary Protein During an Energy Deficit Combined with Intense Exercise Promotes Greater Lean Mass Gain and Fat Mass Loss: A Randomized Trial. American Journal of Clinical Nutrition 2016;103(3):738–746. The randomized-trial evidence underpinning the calculator's higher fat-loss recommendations.