I first heard of Valter Longo on the Kevin Rose podcast. Subsequently, I have seen a lot of copy cat or home grown Fast Mimicking diets. These often include avocados and protein powder, aiming for that 500 calorie range. I am not sure if it was implied or inferred, but I had the impression from Longo that he developed a specific diet, not just a calorie target, to promote atophagy for those 5 Fast Mimicking days. It may be that he just wanted to sell his product, and I didn't buy it nor am I promoting it, but if you accept his research, and do not want to buy his product, you may be better off just doing a true fast.