Eating high glycemic index carbohydrates before running may help maintain muscle strength, neural activation, and tryptophan levels during prolonged exercise, and lead to higher rates of carbohydrate burning and insulin release compared to low glycemic index carbohydrates.

Eating a meal with 1.5 grams of carbohydrate per kilogram of body weight before running for 90 minutes helps maintain muscle strength and nervous system drive during the run better than eating a meal with 0.8 grams per kilogram, and leads to higher use of carbohydrates for energy and a stronger insulin response.

If you eat before working out, your blood sugar and insulin levels spike more during exercise than if you work out on an empty stomach.

When athletes consume carbohydrates before running for a long time, higher rates of carbohydrate use and insulin release are linked to less decline in the brain's ability to fully activate muscles during the run.

Eating a meal high in carbohydrates before doing cardio exercise increases how effectively insulin promotes the building of muscle and fat tissue in the body.

For adults with prediabetes, exercising at 70% of their maximum heart rate helps blood insulin levels return to fasting levels more quickly after eating, which suggests the body is using insulin more efficiently.