{
  "slug": "protein-intake",
  "title": "Protein Intake Calculator",
  "category": "Macros & Intake",
  "category_slug": "macros-intake",
  "tier": 1,
  "summary": "Multiply body weight by grams-per-kilogram rate to estimate daily protein intake in grams.",
  "description": "This calculator estimates daily protein intake in grams by multiplying body weight in kilograms by a user-selected grams-per-kilogram rate (0.8–3.0 g/kg). The default rate of 1.8 g/kg is drawn from the 2016 joint position statement of the Academy of Nutrition and Dietetics, Dietitians of Canada, and the American College of Sports Medicine for athletes. The output provides total daily protein intake and per-meal portions, though individual requirements may vary based on training volume, body composition goals, and metabolic factors.",
  "page_url": "https://fitmetriclab.com/en/tools/macros-intake/protein-intake/",
  "api_url": "https://fitmetriclab.com/api/tools/protein-intake.json",
  "formula": {
    "id": "protein_intake",
    "expression": "\\text{Protein} = w \\times k",
    "variables": [
      {
        "symbol": "w",
        "description": "Weight in kg"
      },
      {
        "symbol": "k",
        "description": "Protein in g per kg of body weight"
      }
    ]
  },
  "inputs": [
    {
      "id": "weight_kg",
      "label": "Weight",
      "type": "number",
      "unit": "kg",
      "default": 75,
      "min": 20,
      "max": 300,
      "step": 0.1
    },
    {
      "id": "g_per_kg",
      "label": "Protein per kg Bodyweight",
      "type": "number",
      "unit": "g/kg",
      "default": 1.8,
      "min": 0.8,
      "max": 3,
      "step": 0.1
    }
  ],
  "worked_example": {
    "inputs": {
      "weight_kg": 75,
      "g_per_kg": 1.8
    },
    "expected_output": "135 g protein/day"
  },
  "result_summary_template": "For a body weight of {weight_kg} kg and a rate of {g_per_kg} g/kg, total daily protein intake is {result}.",
  "methodology": "Multiplies body weight in kilograms by a user-selected grams-per-kilogram rate (0.8–3.0 g/kg). The default of 1.8 g/kg is drawn from Position of the Academy of Nutrition and Dietetics, Dietitians of Canada, and the American College of Sports Medicine (2016) for athletes.",
  "sources": [
    {
      "label": "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. J Acad Nutr Diet. 2016;116(3):501-528.",
      "url": "https://pubmed.ncbi.nlm.nih.gov/26920240/"
    },
    {
      "label": "Jäger R, Kerksick CM, Campbell BI, et al. International Society of Sports Nutrition Position Stand: protein and exercise. J Int Soc Sports Nutr. 2017;14:20.",
      "url": "https://pubmed.ncbi.nlm.nih.gov/28642676/"
    },
    {
      "label": "Institute of Medicine. Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids. National Academies Press. 2005.",
      "url": "https://www.nap.edu/catalog/10490/dietary-reference-intakes-for-energy-carbohydrate-fiber-fat-fatty-acids-cholesterol-protein-and-amino-acids"
    }
  ],
  "faqs": [
    {
      "question": "Why does the calculator default to 1.8 g/kg?",
      "answer": "The 1.8 g/kg default sits in the middle of the range commonly cited for resistance-trained individuals. Literature reviews from the International Society of Sports Nutrition and the Academy of Nutrition and Dietetics suggest 1.4–2.0 g/kg for athletes; 1.8 g/kg is a reasonable midpoint for exploration."
    },
    {
      "question": "Should the rate be based on total body weight or lean mass?",
      "answer": "This calculator uses total body weight because that is the input requested. Lean-mass-based calculations are more precise but require body-composition measurement. For individuals with high body fat, multiplying total weight by a standard rate may overestimate requirements."
    },
    {
      "question": "What is the 0.8 g/kg lower limit based on?",
      "answer": "0.8 g/kg is the Recommended Dietary Allowance (RDA) for protein established by the U.S. Institute of Medicine for sedentary adults. It represents the intake sufficient to meet the needs of 97–98% of healthy individuals in nitrogen balance."
    },
    {
      "question": "Why does the tool show per-meal intake divided by four?",
      "answer": "The per-meal calculation assumes four evenly spaced meals across the day. This is an arbitrary split for convenience; actual meal frequency and distribution depend on schedule, preference, and training timing. Muscle protein synthesis studies show benefit from spreading intake, but optimal frequency remains debated."
    },
    {
      "question": "Can I use pounds instead of kilograms?",
      "answer": "The calculator requires kilograms because the grams-per-kilogram rates in the scientific literature are reported in metric units. To convert pounds to kilograms, divide by 2.205 before entering the value."
    }
  ],
  "related_tools": [
    {
      "slug": "water-intake",
      "title": "Water Intake Calculator",
      "api_url": "https://fitmetriclab.com/api/tools/water-intake.json",
      "page_url": "https://fitmetriclab.com/en/tools/macros-intake/water-intake/"
    },
    {
      "slug": "macro-split",
      "title": "Macro Split Calculator",
      "api_url": "https://fitmetriclab.com/api/tools/macro-split.json",
      "page_url": "https://fitmetriclab.com/en/tools/macros-intake/macro-split/"
    },
    {
      "slug": "alcohol-calories",
      "title": "Alcohol Calories Calculator",
      "api_url": "https://fitmetriclab.com/api/tools/alcohol-calories.json",
      "page_url": "https://fitmetriclab.com/en/tools/macros-intake/alcohol-calories/"
    }
  ],
  "last_updated": "2026-04-22",
  "price": {
    "value": 0,
    "currency": "USD"
  },
  "runs_in_browser": true,
  "disclaimer": "Educational estimate produced from a published formula. Not medical, nutritional, or training advice. Calculations are deterministic — apply the formula to the inputs to reproduce the result."
}