How Much Protein Runners Actually Need
Most runners need 1.2–2.0 g of protein per kg of body weight per day — well above the 0.8 g/kg RDA, which was set for sedentary adults. Where you sit in that band depends on three things this calculator asks about: weekly volume, whether you are cutting calories, and age.
| Situation | Daily target | 68 kg runner |
|---|---|---|
| Under 30 km/week | 1.2–1.4 g/kg | 82–95 g |
| 30–60 km/week | 1.4–1.6 g/kg | 95–109 g |
| 60+ km or marathon build | 1.6–1.8 g/kg | 109–122 g |
| Add if losing weight | +0.4 g/kg | +27 g |
| Age 50+ (5-year steps) | +0.05 to +0.2 g/kg | up to +14 g |
(The calculator rounds daily grams to the nearest 5, so its output can differ from this table by a few grams.)
The 1.2–2.0 band comes from the joint position stand of the American College of Sports Medicine, the Academy of Nutrition and Dietetics and Dietitians of Canada, which puts the protein needed for metabolic adaptation, repair and remodeling at 1.2–2.0 g/kg/d, with higher intakes indicated for short periods of intensified training or energy restriction. The upper tier is backed by direct measurement: using the indicator amino acid oxidation method, endurance athletes who ran 20 km needed an estimated average of 1.65 g/kg, with a recommended intake of 1.83 g/kg, on that training day (Kato et al. 2016) — the study was small (six athletes), but it measured requirements rather than estimating them from nitrogen balance.
Why 20–40 g Per Meal Beats One Big Dinner
Hitting 110 g with a giant dinner does not work like four spread-out doses. Muscle protein synthesis is maximally stimulated by about 20 g of quality protein after typical training (Moore et al. 2009), rising to ~40 g when far more muscle is worked at once — measured after whole-body resistance training (Macnaughton et al. 2016), a ceiling long-run days plausibly share, though that extrapolation has not been tested directly — beyond that, the surplus is increasingly oxidized rather than used for repair. When researchers gave athletes the same 80 g of protein in three patterns over 12 hours, 4 × 20 g every 3 hours beat both 2 × 40 g and 8 × 10 g for muscle protein synthesis (Areta et al. 2013).
What that means in practice:
- Aim for ~0.3 g/kg per meal (about 20–30 g for most runners), 3–5 times a day, every 3–4 hours.
- Breakfast is where most runners fall short — toast and coffee starts you at roughly 5 g. Eggs, Greek yogurt or milk fix it cheaply.
- From age 50 the calculator steps your per-meal dose up in 5-year bands, from 0.30 toward ~0.40 g/kg at 65. This is advisory: dose-response data suggests older muscle needs a bigger per-meal dose (~0.40 vs 0.24 g/kg in ~71 vs ~22-year-olds, Moore et al. 2015), while trials in masters athletes specifically are still small and not conclusive.
The 30-Minute “Anabolic Window” Is Mostly a Myth
You do not need to chug a shake in the parking lot. A meta-analysis of protein-timing trials in resistance training — over 500 participants across 23 studies — found that once total daily protein was controlled for, consuming protein immediately around training had no significant effect on strength or muscle gain; the authors concluded the results “refute the commonly held belief that the timing of protein intake in and around a training session is critical” and that — for muscle gain — total daily intake is the strongest predictor (Schoenfeld et al. 2013).
For runners the practical rules are simpler than the supplement aisle suggests:
- A normal meal within ~2 hours of finishing your run covers the protein side.
- After long runs, carbohydrate comes first — glycogen refill is the endurance priority, with protein supporting muscle repair alongside it (ISSN position stand).
- The “post-run” slot in this calculator exists because it is a convenient, appetite-friendly moment to bank 20–40 g — not because the window slams shut.
What 20–30 g of Protein Looks Like
Daily targets only matter if you can see them on a plate. Typical values from USDA FoodData Central (cooked weight where relevant):
| Food | Protein |
|---|---|
| Chicken breast, 100 g cooked | ~31 g |
| Salmon, 100 g cooked | ~25 g |
| Whey protein, 1 scoop (30 g) | ~24 g |
| 3 large eggs | ~19 g |
| Lentils, 1 cup cooked | ~18 g |
| Greek yogurt, 170 g tub | ~17 g |
| Milk, 250 ml | ~8 g |
A 100 g target is therefore very reachable from food alone: eggs and yogurt at breakfast, a chicken or lentil lunch, a normal dinner and one snack gets you there. Plant-based runners hit the same g/kg numbers with legumes, tofu, tempeh and grains — variety across the day covers the amino acid profile. Track it against your calorie budget with the running calorie calculator if you are managing weight at the same time.