Hi Mehmet, and thank you for your kind feedback. I was so sorry to hear you had problems while on your vegan diet, although not surprised that you didn't do well on the fruitarian diet. Did you seek advice from a vegan nutritionist? While I've certainly come across the theory that some people are genetically predisposed to not do well on a plant-based diet, I don't believe there is any real scientific evidence to prove this theory. Most often it is just some nutrient which is missing from the individual's diet or something quite simple yet profound which just needs tweaking. I would definitely recommend looking into it again, as it's clearly something you must feel strongly about. It would be a shame to write it off altogether if the issue can be remedied.