> How much fruit do you have to eat before it becomes harmful?
Unclear. The aforementioned study fed mice sugar water [1], and cautions against extending its findings to fruit as "natural fructose obtained from plants typically confers metabolic benefits due to its slower absorption rate and the presence of beneficial plant fiber and antioxidants."
It does mention, however, that "human physiology...confronts challenges when metabolizing fructose beyond 25g/day." That's like a cup of grapes, a medium pear or half a mango [2].
I've stopped eating fruit (and carrots, which have fruit-like levels of sugar) with the exception of tart (i.e., less sugary) cherries out of a desire to limit my fructose intake. I was eating raspberries, too, which are much lower in sugar than most fruit, but stopped because of their high levels of oxalic acid, but I do expect to restart raspberries in a few years because I expect my ability to tolerate oxalic acid in my diet to improve slowly over the next few years. (In contrast, high-fructose foods including most fruit are probably gone for good.)
Of course, I'm not asserting that everyone should do as I am doing. There is substantial variation between individuals here.
