I think ones tolerance for high fruit diets has a lot to do with genetics, specificaly related to inherited insulin and leptin resistance, and how much in ones past have we abused or overeaten any type of sugars or carbs. I know for myself, I spent way too many years ( raw since 1974) holding that dream of fruitarianism and spent a lot of time searching the best fruits around the world... never really paying attention to blood sugar levels or anything actually except my ideas and thoughts about how much healthier I'm going to be.... I remember when I went 80/10/10 ( bad idea ) or the Wai diet,, both felt so good at first, but it's hard to pick up the signals from the body as to whether it's good or bad because over the long run, day to day, the potential for a downward spiral can be ever so gradual that we just don't notice ( or care to ), and I did things like eating more and more fruit to make up for low blood sugar swings and lost muscle mass (weight loss in general). Even looking in the mirror can be deceptive, cause it's so gradual and from one day to the next it's hard to notice. There's little doubt in my mind that the sugar high from fruits is, if not addictive, a high that comes just 'too easily'.