Refuel with carbs and protein after hard runs

Carbohydrate after a hard run refills the glycogen your legs used, and protein eaten within about 2 hours boosts muscle protein building. Protein adds little to glycogen refill when you eat enough carbohydrate. Daily totals matter more than exact timing, unless your next hard session is under 4 hours away or carbohydrate intake is low.

Why it works

Exercise uses up muscle glycogen, and carbohydrate eaten afterward refills it. Protein eaten after exercise raises muscle protein building.

What it means in practice

Tell runners to eat a normal meal with carbohydrate and protein within a couple of hours of hard or long runs. When the next session is under 4 hours away, put carbohydrate first. Do not say protein makes glycogen refill faster, and do not recommend spreading protein across meals or a per-meal protein dose.

The evidence

• Kerksick, C.M., Arent, S., Schoenfeld, B.J. et al. (2017). International society of sports nutrition position stand: nutrient timing. Journal of the International Society of Sports Nutrition.

  Adding protein (0.2-0.5 g/kg/h) to carbohydrate sped glycogen resynthesis only when carbohydrate intake was below 1.2 g/kg/h; at that intake or higher, trials found no added benefit. Protein eaten from immediately to 2 hours after exercise clearly raises muscle protein synthesis, though timing ranks below meeting 1.4-2.0 g/kg of protein a day. Timed carbohydrate matters most when glycogen must be restored in under 4 hours, or when carbohydrate intake is inadequate. Otherwise, with daily carbohydrate matching energy needs, the importance of timed intake is notably decreased.

Why we call confidence medium

The ISSN nutrient-timing stand supports this advice, and carbohydrate refilling glycogen is well established. The stand comes from a society with supplement-industry ties, and its protein-timing evidence is mostly short lab studies after weight training.

Where it applies

Healthy exercising adults, including recreational runners. The protein-timing evidence comes mostly from resistance exercise.

Does not apply to: claims that a precise post-run window decides results when the next session is a day or more away; people with kidney disease or medically restricted protein intake; protein supplement product recommendations.