Yeah I've been using monk fruit and stevia (with erythritol) as a 1:1 sugar substitute in baking, pancakes, coffee sweetener for some time now and never felt intestinal distress myself but I don't consume large amounts of it anyway since my tastebuds long ago re-sensitized to sweetness. Even if I use it to just replace half of the sugar in a batch of cookies or muffins it makes for a big drop in calories without affecting the taste.

My friend who was panicking about this wasn't comprehending that from the few numbers I could dig up about this "study" these people were essentially consuming enough to be equivalent to over a liter of soda a day which is terrible for you to begin with.