A person fasts for 30 days During this time they lose 16 kg

A person fasts for 30 days. During this time, they lose 16 kg of body mass – 13 kg of fat and 3 kg of protein and carbohydrates combined. They have a constant surface area of 1.7 m², and they sleep (35 Cal/hr m²) for 8 hr per day. Assume that the fat had no water content and that the protein and carbohydrate mass lost were 75% water. What was their average metabolic rate for the waking part of their day?

Solution

1 gram fat gives 9 calories

1 gram proteins and carbohydrate gives 4 calories

Lost body mass or energy= 13000*9 + 3000*4

=117000+12000

=129000 calories

Water = 75% of 12000

=75/100 *12000

=9000

So total Loss of energy= 129000-9000= 120000 cal or 120 Kcal

Loss per day = 120/30 = 4 Kcal or 4000 cal

Average metabolic rate for waking part of the day= ?

[ 8 hours * 35 cal +16 hours * x cal ] * 1.7 = 4000

x = 159.457 cal per hour m² (This is the metabolic rate in waking part of the day.