Even small amounts of trigger foods like gluten or beans can confound elimination diet experiments due to the immune system's sensitivity.

“it's this is not a macronutrient based weight gain body composition equation where it's like I can have one chocolate chip it's like no your immune system is exquisitely sensitive you can't have one chocolate chip you know and that's not specifically the example I mean to use there but you can't have one you know being you know that's it that could be enough to trigger your immune system and that would confound the whole experiment”