Research

Energy balance

A high-carbohydrate diet (50-70% of energy) improves endurance performance, sprint speed, and recovery compared to low-carbohydrate diets by maximizing muscle glycogen stores.

If you are an endurance athlete (runner or cyclist), ensure 50-70% of your daily calories come from carbohydrates. This maximizes muscle glycogen, which is critical for maintaining intensity, delaying fatigue, and improving race times. Focus on foods with low to moderate glycemic indices.

ModerateSupportsHIGH confidence
A high-carbohydrate diet allows for greater glycogen storage in muscles, which is critical for maintaining training intensity... The results showed that participants on the high-carbohydrate diet achieved a final sprint speed of 14.4 ± 2.2 km/h, surpassing the speed of 13.3 ± 2.4 km/h in the low-carbohydrate group (p < 0.05)... The average completion time for the race was 50.0 ± 7.0 minutes in the high-carbohydrate group, representing a significant improvement compared to the time of 51.9 ± 8.3 minutes in the low-carbohydrate group (p < 0.05)
Katarzyna Szafrańska et al. · Quality in Sport · 2024

Why this rating

The paper is a review citing multiple studies (including a specific runner study with p<0.05), but it aggregates findings rather than presenting a single new primary trial.

Source

Impact of Nutritional Methods On Physical Performance Parameters

Katarzyna Szafrańska et al. · Quality in Sport · 2024

DOI 10.12775/qs.2024.35.56362

narrative_review
Read the paper
DOI resolved against Crossref · corpus check 2026-06-10

This is one finding among thousands. Every one is graded and traced to its source, so you can see what the evidence actually supports. Browse the research →