Yes crash diets worked for me. I gained the weight back, but that was my fault because I did not change my lifestyle.
About 90% of people who lose weight through dieting gain every pound back regardless of their weight-loss method..taken from a Penn State article..http://www2.hmc.psu.edu/healthinfo/womens/10/000053.htm
The problem with starvation diets is that muscle gets burned in addition to fat stores. There is another PSU article (which I can't find now) that found for the usual course of dieting (not necessary a starvation diet) a little over 20 % of total weight loss is due to muscle loss and not fat loss. With starvation diets, the immune system may get depressed and electrolyte disturbances can occur.
Sudden death has been reported with extreme dieting. In the USA, there was the low protein diet craze of the 70's. This fell out of vogue because healthy people where dying unexpectedly. This diet was then replaced by the low fat diet which is also now out of favor..Every generation has it's diet fad.