Evidence-based protein goals by activity and objective.
What does daily protein intake mean?
Protein is an essential macronutrient made up of amino acids, 9 of which are essential, meaning the body cannot synthesise them and must obtain them from food. Adequate protein intake is required for muscle maintenance and growth, immune function, enzyme and hormone synthesis, tissue repair, and satiety signalling.
The Recommended Dietary Allowance (RDA) of 0.8 g/kg body weight per day is the minimum needed to prevent deficiency in sedentary adults. That is a floor, not a target. The ISSN Position Stand (Jäger and colleagues, 2017) recommends 1.4–2.0 g/kg/day for exercising adults, with higher targets for strength athletes (1.6–2.2 g/kg) and those in a caloric deficit (up to 2.2–2.4 g/kg to minimise muscle loss).
Older adults have increased protein needs due to anabolic resistance, the blunted muscle protein synthesis response to a given protein dose. The PROT-AGE Study Group (Bauer et al., 2013) recommends at least 1.0–1.2 g/kg/day for healthy older adults, and up to 1.5 g/kg/day for those who are ill or recovering from injury.
Protein distribution throughout the day matters as much as total intake. Studies show that spreading protein relatively evenly across 3–4 meals (each containing 20–40 g of high-quality protein) maximises muscle protein synthesis compared to concentrating most protein in a single meal.
Reference ranges (protein g/kg body weight)
| Population | Recommended (g/kg/day) |
|---|---|
| Sedentary adults (RDA) | 0.8 |
| Active adults / recreational exercise | 1.2 – 1.4 |
| Endurance athletes | 1.2 – 1.6 |
| Strength / power athletes | 1.6 – 2.2 |
| Weight loss (caloric deficit) | 1.8 – 2.4 |
| Older adults (≥65 years) | 1.0 – 1.5 |
When should you see a doctor?
Most healthy adults can safely increase protein intake without medical supervision. However, individuals with chronic kidney disease (CKD stages 3–5), advanced liver disease, or PKU (phenylketonuria) require protein restriction under medical and dietitian supervision. If you have a known metabolic condition, consult a registered dietitian before significantly changing your protein intake.
Frequently asked questions
How much protein do I need per day?
Protein needs vary by activity level. The RDA (minimum to prevent deficiency) is 0.8 g/kg/day. Active adults and those wanting to build or maintain muscle typically need 1.2–2.0 g/kg/day. Strength athletes and those in a calorie deficit benefit most from 1.6–2.2 g/kg/day. The ISSN (International Society of Sports Nutrition) concludes that 1.4–2.0 g/kg/day is safe and effective for exercising adults.
Is too much protein bad for you?
For healthy adults with normal kidney function, protein intakes up to 3.5 g/kg/day appear safe. Concerns about high protein damaging kidneys in healthy people are not supported by current evidence, though people with existing kidney disease should restrict protein and consult a dietitian. Very high protein diets may crowd out other macronutrients if total calories are not sufficient.
What foods are highest in protein?
Animal protein sources with the highest protein density (grams per 100g): chicken breast (~31g), tuna (~30g), Greek yoghurt (~10g), eggs (~13g), beef (~26g). High-protein plant sources include tempeh (~19g), edamame (~11g), lentils (~9g cooked), and tofu (~8g). Animal sources generally have higher bioavailability and a complete amino acid profile.