Everyone has heard that athletes eat bananas because they’re high in potassium and prevent muscle cramps; but is that true?
One ripe uncooked banana (1 serving; 115 grams) contains approximately 375 mg of potassium.[1] However, several foods contain potassium in similar or greater quantities than bananas: meat (pork, beef, and poultry), potatoes, collards, beans, watermelon.[2]
Eating bananas post-exercise may not increase the potassium in your blood in any meaningful way. One small randomized controlled trial asked 9 men to complete 60 minutes of exercise in the heat and then eat 0, 150, or 300 grams of bananas. The participants followed the exercise-and-banana protocol 3 times, on 3 different days, eating a different quantity of bananas each time. The study found that eating up to 300 grams of bananas caused a very small, but clinically meaningless, increase in plasma potassium concentration, 30 to 60 minutes after eating the bananas.[3] These results show that eating bananas is unlikely to treat or prevent a muscle cramp that is caused by potassium depletion. However, larger high-quality trials are needed to fully understand the role of potassium in muscle cramps and how to prevent/treat them.