The Protein Calculator is only an estimate of daily protein requirements based upon factors including assigned sex, goal weight, height, activity level, and fitness goals (weight loss, maintenance, or muscle gain). This calculator uses evidence-based protein intake recommendations ranging from 1.2-2.7 grams per kilogram of body weight, derived from systematic reviews and position statements by the International Society of Sports Nutrition (ISSN) and the Academy of Nutrition and Dietetics.

The Protein Calculator may not accurately reflect the protein needs of individuals with specific medical conditions such as kidney disease, liver disease, or metabolic disorders requiring protein restriction, pregnant or lactating women (who have increased protein requirements), children and adolescents (who have different growth-related needs), the elderly (who may benefit from higher protein intake to prevent sarcopenia), or competitive athletes with specialized training demands. This calculator should not be used as a sole diagnostic tool for nutritional planning.

Protein recommendations are stratified by goal: weight loss (2.0 g/kg) incorporates higher protein to preserve lean muscle mass during caloric restriction, as research demonstrates that elevated protein intake during energy deficit prevents muscle loss and enhances satiety; maintenance (1.4 g/kg) reflects adequate intake for healthy adults; and muscle gain (1.8 g/kg) is based on meta-analyses showing that 1.6-2.2 g/kg maximizes muscle protein synthesis when combined with resistance training. Activity level adjustments (0.95x to 1.1x) account for increased protein turnover during exercise.

Per-meal protein calculations assume three meals per day and are based on research indicating that 20-40 grams of high-quality protein per meal optimally stimulates muscle protein synthesis, with approximately 0.4 g/kg per meal being the ceiling for anabolic response in most individuals. The calculator does not account for protein quality, amino acid composition, timing relative to exercise, or distribution across more than three meals, all of which can influence protein utilization. Individual protein needs may vary based on factors including body composition, training status, total caloric intake, and concurrent carbohydrate consumption.

The Protein Calculator does not determine eligibility for any nutritional supplements or interventions. Consultation with a registered dietitian or healthcare provider is recommended for personalized protein recommendations, especially for individuals with chronic health conditions, special dietary requirements, or specific athletic performance goals.

Medical References:

• Jäger, R., et al. (2017). International Society of Sports Nutrition Position Stand: Protein and exercise. Journal of the International Society of Sports Nutrition, 14, 20.
• Morton, R.W., et al. (2018). 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, 52(6), 376-384.
• Phillips, S.M., & Van Loon, L.J.C. (2011). Dietary protein for athletes: From requirements to optimum adaptation. Journal of Sports Sciences, 29(sup1), S29-S38.
• Academy of Nutrition and Dietetics. (2024). Position of the Academy: Nutrition and Athletic Performance.
• Carbone, J.W., & Pasiakos, S.M. (2019). Dietary protein and muscle mass: Translating science to application and health benefit. Nutrients, 11(5), 1136.