ColinJ said:Hang on a second, there's something not right there...
Okay, first thing - a Joule is equivalent to a force of 1 Newton acting over a distance of 1 metre. The force on 1 kg due to gravity is approximately 9.81 Newtons so you are out by a factor of about 9.81 there.
Secondly, 4.18 Joules are equivalent to about 1 calorie, not 1 kcal which is what food energy is usually measured in.
Thirdly, we haven't been taking into account my body mass which was about 80 kg at the time.
Fourthly (?), the body isn't 100% efficient. In fact it is pretty inefficient. I had a quick hunt around and saw figures in the range 15%-25% so let's call it 20%.
Let's do the calculations again.
Work done = (50 + 80) * 9.81 * 750 Joules = 956,475 J. Converting that to calories ~= 228,822 cals ~= 229 kcals.
But taking a 20% efficiency figure, I'd actually have burned about 5 times that or approximately 1,150 kcals. That sounds more like it! I was eating 3 good meals a day, but not going over the top. The extra kcals required were coming from my nightly trips to the pub!
Yes, I had a long think about this on my commute home and am sorry to say my post was in haste, maketh waste, with errors.... BIG errors.
A five star embassasment.
I checked my spreadsheets when I got home and you are correct to point out my errors.
1/10 Jimbo.