How much protein do athletes need?

ISSN guidance places athlete protein between 1.4 and 2.2 grams per kilogram of bodyweight daily. Endurance athletes sit near the lower end, strength athletes higher, and those in a calorie deficit toward the top to protect muscle.

Why are carbohydrates set by training hours?

Carbohydrate is the primary fuel for hard training, so needs scale with workload. Light weeks call for around four grams per kilogram while very high volume can demand eight to ten grams per kilogram to refill muscle glycogen.

How is fat calculated?

Fat fills the remaining energy after protein and carbohydrate are set, with a floor of about 0.8 grams per kilogram to protect hormone production. This keeps total calories aligned with your training load and goal.

How does the weight-cut option work?

Choosing a weight cut raises protein to spare muscle, lowers carbohydrate by one band, and trims total energy by roughly fifteen percent to create a moderate deficit. This favours fat loss while preserving training quality.

Are these exact requirements?

No. They are evidence-based starting points from ISSN position stands. Real needs vary with metabolism, climate, sex, and training phase, so adjust over a few weeks based on bodyweight changes and how your sessions feel.

Athlete Macro Calculator

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Athletes need more than a generic calorie number — they need fuel matched to the demands of their sport. This calculator applies ISSN per-kilogram guidelines to turn your bodyweight, training volume, and goal into concrete daily gram targets for each macronutrient.

How it works

Protein is set per kilogram of bodyweight by goal, and carbohydrate scales with weekly training hours:

protein = 1.4–2.2 g/kg   (endurance → strength → cut)
carbs   = 4 / 6 / 8 / 10 g/kg   (by <5 / 5-10 / 10-15 / >15 h per week)
fat     = remaining energy / 9 kcal/g, floored at 0.8 g/kg

Energy is estimated from bodyweight scaled by training load; a weight cut trims it by about 15 percent and drops carbohydrate one band to create a deficit while keeping protein high.

Example and tips

A 75 kg strength athlete training 8 hours a week gets roughly 135 g protein, 450 g carbohydrate, and fat filling the balance — around 2,800 kcal. Distribute protein across three to five meals, time most carbohydrate around training, and keep fat above the floor for hormonal health. Re-check your numbers as bodyweight changes and lean on real performance and recovery as the final arbiter, not the calculator alone.