What it is
Sweeteners your small intestine can't finish absorbing, so your gut microbes finish them for you. The laxative warning on the pack is the receipt.
Why your biology objects
Poorly absorbed in the small intestine, they draw water into the bowel and ferment in the colon — gas, bloating, and an osmotic laxative effect at dose. (Xylitol is also genuinely toxic to dogs.) Not a poison; a sign the recipe is engineered around a number, not a kitchen.