The UK reality show "I'm a celebrity... Get me out of here!" (see link) might not be to everyone's liking, but one thing's for sure - it's a great aid to weight-loss.
Contestants can lose something like 2 stones whilst in the jungle (approx. 2 weeks), and I think this is pretty impressive.
I propose
a similar facility for non-celebrities, but sans Antandec and TV coverage.
Each 'contestant' is subjected to thorough psychological profiling, and is only grouped with other compatible 'contestants' in order to keep conflict to a minimum.
Meals are earned in the same way as in the show - 'Bush tucker trials'. Thankfully, none of these trials are of the icky insect-eating variety - trials are either mental or physical challenges.
Not only would the 'contestants' leave the jungle slimmer, they would hopefully also learn something about themselves and their decadent, consumerist lifestyles.
Rice anyone?