When it comes to competing at the highest levels or any gym workouts, minor changes in your dietary habits could certainly impede your performance.
Fruits high in tannins are banned before any sports competitions and gym workouts. They are quince, persimmon (especially unripened), chokeberries, and pomegranate. The skin of banana also contains tannins. The strange taste in mouth after having persimmon or quince is due to tannins, which usually bind to the proteins in saliva, causing them to aggregate and resulting in a dry feeling in the mouth.
After mixing with stomach acid, tannins form a sticky ball-shaped conglomeration called “phytobezoar”. Moreover, tannins are astringents and can bind and precipitate proteins, starch, and even minerals in your foods.
Therefore, we strongly recommend that you avoid having fruits high in tannins prior to your exercise activities especially along with your pre – exercise meals, as they cause a sticky and unabsorbable conglomeration of foods (bezoar) trapped in your gastrointestinal system, making you feel very heavy on your stomach and hampering your performance.
Abazar Habibinia, MD, DFN
CEO of the Canadian Academy of Sports Nutrition