Add in the rider to eat the bread, and with enough bread you generate 50,000 calories enough to power a daily 12km commute. According to the latest edition of New Scientist a rider doing a daily 12km commute would over the course of a year burn 50,000 calories – the equivalent of 22kg of brown bread.

Here’s how they worked it out…

A kilo of brown bread has a carbon footprint of 1.1kg, so if you fuelled up exclusively on brown bread (can you spot the slight flaw in their calculation?) your commute’s carbon footprint would be 26.4Kg as opposed to a bus for the same distance which has a footprint of 164Kg of carbon per commuter. Phew! And you thought science was boring. 

And there’s more, riding a bike for an hour produces enough energy to power a low energy light bulb for eight hours. A strong rider should be able to power a conventional 100watt bulb for two hours – on an hour’s riding. Buy yourself a Pedal-A-Watt and you could do just that or you could power the television or store the energy in a battery for later which sounds a bit boringly sensible. You can even build your own Pedal-A-Watt using a turbo trainer and some bits and pieces from an electrical store. That’s this weekend sorted then…