Apples are often called one of the healthiest fruits on Earth — crisp, juicy, and packed with fiber and vitamins. But doctors say that while one or two apples a day can support good health, too many can actually cause unexpected side effects that most people don’t realize.

Apples contain a natural sugar called fructose. In small amounts, it’s harmless — but eating too many apples can overload the digestive system, leading to bloating, stomach cramps, and diarrhea in sensitive people. Those with irritable bowel syndrome (IBS) are especially prone to these effects.

Another concern is the seeds. Apple seeds contain amygdalin, a compound that releases small amounts of cyanide when digested. While eating a few seeds accidentally won’t harm you, consuming large amounts regularly can be dangerous over time.

Doctors also warn that apple juice — often mistaken as “healthy” — can spike blood sugar levels quickly, especially in diabetics. The fiber that slows sugar absorption in whole apples isn’t present in juice, making it easier for blood sugar to rise sharply.

So while the old saying goes, “An apple a day keeps the doctor away,” the truth is more balanced — moderation is key. One apple a day truly can support your health, but turning it into a habit of four or five could do more harm than good.