SUMMARY

TRAINING THE GUT

Reductions in sympathetic nervous system activity help explain why gut blood flow at standardized exercise workloads is better maintained after long-term exercise training.

Animal studies show that the activity of SGLT1 transporters can be manipulated by changing dietary carbohydrate content.

Supplementing your diet with sugars like glucose and fructose for even a few days can accelerate how quickly these sugars empty from your stomach; if you plan to eat a good amount of carbohydrate during competition (e.g., more than 50 grams per hour) but don’t want to follow a super high-carbohydrate diet for weeks on end, then this may be a way to train your gut to better tolerate carbohydrate intake during competition.

Eating a fat-rich diet speeds the emptying of fat from your stomach; what this means on a practical level for athletes isn’t known scientifically, but perhaps it could be advantageous for an athlete who plans to eat more fat than usual during competition (like an ultramarathoner competing over many hours or several days).

Repeatedly exposing your stomach to large volumes of fluid during training (e.g., 25–30 ounces per hour) may lessen perceptions of stomach discomfort over time, which, in theory, could allow you to better maintain hydration when you’re sweating heavily (e.g., more than 35 ounces per hour).