The cholesterol change is easily explained - meat and dairy are two of the main sources of LDLs (“bad” cholesterol) in the western diet. The diabetes one is ha

The cholesterol change is easily explained - meat and dairy are two of the main sources of LDLs (“bad” cholesterol) in the western diet. The diabetes one is harder to explain/link, as there are too many variables. One possibility is that the twin that went vegan ate fewer sugary snacks due to the fact that most such things are not vegan.