# People eating and gaining energy

Let's say we have 100 grams of chocolate which has 571 kilocalories (so it's about 2.4 megajoules) and we have barbell which weights 100 kilograms and need to lift it to 0.5 meters height.

So how many times you can lift it eating only 100 grams of chocolate? Let's use potential formula $$E=mgh$$ n – how many times you lift $$E=nmgh$$ $$n=\frac{E}{mgh}$$ $$n=\frac{2.4\cdot 10^6J}{100kg\cdot10\frac{m}{s^2}\cdot0.5m}=4800$$ So I get 4800 times, but I doubt it's true. So where and how many (approximately) our gained energy disappears, I mean becomes other kind of energy?

-
You are ignoring the energy exchanges of the body.The cells in the muscles have to eat energy and keep the temperature at 37C and there is infrared radiation in addition to chemical losses and lifting themselves up along with the barbell. This question is for a biology/physiology forum. –  anna v Jul 12 '11 at 15:38