Blueberries also have fructose, a natural sugar. Some people have a mild fructose malabsorption—meaning their gut can’t process it efficiently.
Do Blueberries Cause Black Poop In Babies at Randy Eubanks blog
When fructose isn’t absorbed properly, it pulls water into your intestines. That creates a gentle (or not-so-gentle) laxative effect. So basically, blueberries are giving you a sugar-water enema.
And no, that’s not a compliment—but it’s not entirely an insult either. It’s just science with a side of irreverence.
