On Tuesday September 15th 2009 Eddie Izzard, comedian and film star, completed 43 marathons in 51 days for Sport Relief, raising over £200,000 in the process.

However, while this fact is amazing in itself, what is also interesting is that during this mammoth task Eddie Izzard didn't lose any weight. In fact he actually added weight!

Eddie Izzard, during each marathon, burnt 3,000 calories. At rest he would have burnt 2,000 calories a day. This means that to lose zero weight Eddie would have needed to eat 5,000 calories a day.

Fine, this is something rowers and Tour De France cyclists do during both the race and training.

The key fact though for those people looking to lose weight via exercise alone is that you can do all the exercise in the world, but if your calorie intake matches your calorie expenditure you will fail to lose any weight at all.

Food for thought, as it were.