Body fat is metabolized, supplying 9.30 kcal/g, when dietary intake is less than
ID: 2115143 • Letter: B
Question
Body fat is metabolized, supplying 9.30 kcal/g, when dietary intake is less than needed to fuel metabolism. The manufacturers of an exercise bicycle claim that you can lose 0.500 kg of fat per day by vigorously exercising for 2.00 h per day on their machine. (a) How many kcal are supplied by the metabolization of 0.500 kg of fat? (b) Calculate the kcal/ min that you would have to utilize to metabolize fat at the rate of 0.500 kg in 2.00 h. (c) What is unreasonable about the results? (d) Which premise is unreasonable, or which premises are inconsistent?
Explanation / Answer
(a) 4.65 x 10^3 kcal
(b) 38.8 kcal/min
(c) This power output is higher than the highest value on Reference, which is about 35 kcal/min (corresponding to 2415 watts) for sprinting.
(d) It would be impossible to maintain this power output for 2 hours (imagine sprinting for 2 hours!).