After raising £15,000 in a parachute jump for the National Society for Epilepsy, former weatherman Ian McCaskill is taking part in the charity's first sponsored slim, to run from January to March.
A spokeswoman for the charity said: "We're always looking for new ways to fundraise, and a post-Christmas sponsored slim seemed a good idea."
The charity will be encouraging its supporters to take part. Event organiser Laura Larrett said: "We don't just want people to rush to lose the most weight in the shortest time. That could be dangerous and counter-productive, especially for people on medication for a long-term condition like epilepsy.
"Instead we hope to provide the incentive for people to lose weight gradually and healthily, and maintain a healthier lifestyle."
Participants will be asked to supply before and after photos to the charity and write a log of how their diet and lifestyle has improved.