Question

An individual is consuming 10g of nitrogen per day and losing 12g of nitrogen per day. What total amount of lean body mass would they lose over the course of 8 days? Give a numerical value only (without units). Assume the majority of the nitrogen loss originated from skeletal muscle proteins and that muscle is about 75 % water and 25% protein. Also recognize that tissue atrophy results in the loss of all components of tissue, including water. Lastly, about 16% of the mass of body proteins is nitrogen, or there is 1g of N for every 6.25g of body proteins

Answer 1

Taken nitrogen 10g per day

Lost nitrogen 12g per day

Muscle has 25% protein.

Nitrogen of body protein mass is 16%

Daily loss is 2 g , which refers 20% loss of Nitrogen from the consumed nitrogen.

10 g accounts for 16% of protein

Loss of 20% consumed nitrogen accounts for loss of 0.2g of protein on day 1 from 6.25 g of body mass.

Remaining is 6.05 g of body protein in which 16% protein is 0.97 g (0.968 is rounded off to 0.97)

On day 2 again 20% loss results in loss of 0.194 g of loss that makes a 5.856 g of remaining body protein , in which 16% is 0.94 g.

On day 3 from 0.94 g 20% loss gives 0.19 g loss that results in total protein weight 5.67 g.

In 5.67 g 16 % gives 0.9.

On day 4, 20% loss causes to lose 0.18 g of protein

This results in the total protein weight of 5.49 g.

In 5.49g 16% is 0.88g

On day 5, from 0.88 g, 20% loss results in 0.18 g

Remaining total protein is 5.31g

In 5.31 g, 16 % of protein is 0.85 g

On day 6, 20% loss of protein from 0.85 g of protein is 0.17 g.

Remaining total protein is 5.14 g

In 5.14 g 16% is 0.82

On day 7 from 0.82 g 20% loss is 0.16g

Remaining total protein is 4.98g

In 4.98 g 16% is 0.8

On day 8, from 0.8 g 20% loss is 0.16

Remaining protein after day 8 is 4.82g

So, finally after 8 days from 6.25 g to 4.82 g of protein is left, which has resulted in a total loss of 1.43 g of protein.