When I was very young I devised my own diet, it did work (I lost a lot of weight), but honestly I learnt nothing about healthy eating so put a lot of it back on again shortly after. Really, the best way to lose weight long term is slowly, by changing habits into long lasting healthy ones, it may take longer but the results will be lasting.
I've never done a particular diet, but I did use to starve myself sometimes if I weighed more than I wanted. I would sometimes not eat for a day. The longest I went was 48hrs. It did me no harm, and I lost the weight I wanted, but I don't have the will power to do that anymore.