Apple

Apples are about 85% water with most of their carbs as natural sugars — roughly equal parts fructose and glucose, plus a small amount of sucrose. The fiber is largely pectin (a soluble fiber that gels with water) concentrated in the flesh, with insoluble fiber in the skin. The polyphenols, also mostly in the skin, are why "an apple a day" has held up reasonably well in cardiovascular epidemiology: regular apple eaters show modestly lower LDL and better arterial function.

FODMAPs and IBS

Apples contain more fructose than glucose — a ratio that matters because excess fructose (fructose without enough glucose to ride along) is poorly absorbed in the small intestine. They're also a source of sorbitol. For people with IBS or fructose malabsorption, a whole apple often triggers bloating, gas, and loose stools within hours. Smaller portions, peeled apples, or cooking (which doesn't change FODMAP content, but is sometimes better tolerated) are the usual moderation strategies.

Practical notes

Apple juice concentrates the fructose without the fiber and is a frequent trigger of "toddler's diarrhea." Eating apples with the skin on roughly doubles the fiber and polyphenol load over peeled apples. Organic vs. conventional matters for pesticide residue — apples are on the EWG "Dirty Dozen" most years — though the absolute amounts remain well below safety thresholds.