Question 17.5: People living in affluent societies generally know very litt...
People living in affluent societies generally know very little about starvation. Most feel that death is imminent if food is withheld for only a week. However, we know that 1.00 kg of human body fat contains about 33.1 MJ of metabolizable energy, and it would be useful to know:
a. The mass of body fat consumed per day if one uses 10.5 MJ of energy in normal activities.
b. How many days of total fasting are required to lose 10.0 kg of body fat.
a. A fasting person requiring 10.5 \text{MJ} of metabolizable energy per day consumes about
\dot{m}_\text{fat} = \frac{10.5 \text{MJ/d}}{33.1 \text{MJ/kg body fat}} = 0.317 \text{kg of body fat/d}
b. The number of fasting days required to lose (consume) 10.0 \text{kg} of body fat is
t = \frac{m_\text{fat}}{\dot{m}_\text{fat}} = \frac{10.0 \text{kg of body fat}}{0.317 \text{kg of body fat/d}} = 31.3 \text{d}