> Roger Thorpe wrote:
>

>> So here's another back of envelope calculation.
>>
>> Embedded energy in manufacture and distribution of confectionery =
>> 43MJ/kg. [1]
>> Nutritional energy in chocolate 22MJ/kg [2]
>> cycling 1km to shop at 20km/hr = 100 watts for 3 minutes = 1.8 kJ.

>
>
> 100 * 3 * 60 / 1000 = 18, and muscles are about 25%% efficient.
>

>> Total energy used = 1.8 *43/22 = 3.5 kJ per km
>> Driving = 2700kJ per km [3]
>>
>> so cycling seems to be in the range of 100 to 1,000 times more energy
>> efficient than motoring. I think that you'd have to find some pretty
>> exotic food (or an arithmetical error in my analysis) to make that
>> bit of hyperbole from Chris Goodall stand up.

>
>
> Cycling is a lot more efficient than walking.