So your fat, eat less and do more exercise, not frikking rocket science is it! Fad diets are all about doing just enough that you lose some weight but not enough to actually make you keep it off once you stop!
If you are fat accept you eat too much and do too little, pretty simple! Cut out the take aways and eat a sensibly, increase exercise and hey presto!
There was actually an interesting documentary on channel 5 a few weeks back where some Aussie guy put some yank on a purely liquidised fruit/veg diet, did the trick damn fast, saved his bacon too! Took the p1ss out of any 5:2 diet!