Question

An average daily intake of energy for humans is around 2000 kcal/day. However, this varies and is dependent upon many factors such as health, age, sex, and activity level. But we will use the 2000 kcal/day for our sample problems that follow. Let's say we have a healthy 70kg male. A 70kg male contains about 480g of glycogen We have the same 70kg healthy male and he contains around 6000g of protein. The 70kg male contains 12,000g of fat. Theoretical Question: How many days could this man survive without food on each type of fuel? Please show your work!​

Answer 1

The theoretical survival time for a 70kg male on different energy reserves is approximately 0.984 days on glycogen, 12.3 days on protein, and 55.8 days on fat, assuming an average daily energy requirement of 2000 kcal/day.

Step-by-step explanation:

The question asks how long a healthy 70kg male with specific amounts of carbohydrates (glycogen), protein, and fat could survive without food, using each of these reserves as fuel. To calculate this, we need to know the caloric content of each type of fuel and the average daily intake of energy by humans.

Firstly, 1 gram of glycogen stores approximately 4.1 kcal, 1 gram of protein contains 4.1 kcal, and 1 gram of fat contains 9.3 kcal.

To calculate the number of days he can survive on each type of fuel, follow these steps:

1. Calculate the total available energy from each type of fuel by multiplying the total grams by the kcal per gram (glycogen: 480g * 4.1 kcal/g = 1968 kcal, protein: 6000g * 4.1 kcal/g = 24600 kcal, and fat: 12000g * 9.3 kcal/g = 111600 kcal).
2. Divide the total energy for each type by the average daily requirement of 2000 kcal/day. This gives us the number of days he could survive on each nutrient reserve without food (glycogen: 1968 kcal / 2000 kcal/day = 0.984 days, protein: 24600 kcal / 2000 kcal/day = 12.3 days, fat: 111600 kcal / 2000 kcal/day = 55.8 days).Note that these numbers are theoretical and do not take into account that the body's metabolism would slow down in a starvation situation, that the body requires a mix of nutrients, and that burning protein for energy would also consume muscle tissue, which could be detrimental to health.