Protein Needs by Life Stage and Goal

There is no single "right" protein number — your target shifts with your age, biological stage, training, and goals. This guide breaks down what changes and why, so you can place yourself in the right range and adjust the calculator inputs accordingly.

All ranges are grams per kilogram of body weight per day, drawn from the International Society of Sports Nutrition, the USDA Dietary Reference Intakes, and the PROT-AGE recommendations for older adults. They are starting points for healthy adults, not medical advice.

Women

Target: 1.0–2.0 g/kg

Women need the same protein per kg as men — there is no separate female requirement. The myth that women need less comes from average body size, not biology. Women building muscle, pregnant or nursing (see below), or in perimenopause benefit from the higher end. Resistance training plus adequate protein is especially important for women around menopause, when declining estrogen accelerates muscle and bone loss.

Adults over 60

Target: 1.0–1.5 g/kg

After about 60, the body becomes less responsive to protein — a phenomenon called anabolic resistance. To get the same muscle-building signal, older adults need more protein per meal (aim for 0.4 g/kg per meal) and more per day. The PROT-AGE study group recommends 1.0–1.2 g/kg minimum, rising to 1.2–1.5 g/kg during illness or stress. Our calculator adds +0.2 g/kg automatically for users 60 and over.

Athletes and regular lifters

Target: 1.6–2.2 g/kg

The International Society of Sports Nutrition position stand recommends 1.4–2.0 g/kg for most athletes, with strength athletes benefiting from the upper end (1.6–2.2 g/kg). Endurance athletes also need more than once thought — 1.2–1.6 g/kg — to support recovery and prevent lean mass loss during high training volume. Spread intake across 4–5 meals for best results.

Vegetarians and vegans

Target: +5% to +10%

Plant proteins are slightly less digestible and some are lower in key amino acids like leucine. The fix is not complicated: eat slightly more total protein (the calculator adds 5% for vegetarian, 10% for vegan), choose dense sources like tofu, tempeh, seitan, and lentils, and combine legumes with grains across the day. A well-planned plant diet fully supports muscle gain and health.

Teenagers (13–17)

Target: 0.85–1.3 g/kg

Teens are still growing, so their needs sit above the adult RDA. The USDA sets 0.85 g/kg for sedentary teens, rising with activity. Active teen athletes should aim for 1.2–1.6 g/kg. Because teens are still developing, the priority is a balanced, whole-food diet rather than supplements — and anyone under 18 should consult a pediatrician or dietitian before adopting a high-protein diet.

Pregnancy and breastfeeding

Target: 1.1–1.3 g/kg

Protein needs rise during pregnancy (to about 1.1 g/kg in the second and third trimesters) and stay elevated during breastfeeding (about 1.3 g/kg). Extra protein supports fetal growth, placental development, and milk production. This calculator is built for healthy non-pregnant adults — pregnant and nursing individuals should work with their healthcare provider for a personalized target.

How to use these ranges with the calculator