Question

A person who is starving, that is not having food, and is surviving only on the water will have
A. More urea in his blood
B. Less urea in his urine
C. Fewer fats in his urine
D. More glucose in his blood

Answer 1

Hint: During fasting there is no intake of food and levels of energy decreases. Humans are ureotelic which means they excrete urea.

Complete answer:The concentration of urea in the renal medulla plays a key role in the countercurrent mechanism or urine concentration.
Reduced quantity of urea produced as a consequence of decreased dietary protein consumption is of sufficient magnitude to deplete renal medullary urea.
Formation of urine with decreased specific gravity values will occur even though the kidneys are normal.
Fasting plays an important role in adaptive cellular responses that reduce oxidative damage and inflammation, optimize energy metabolism, and bolster cellular protection.

Additional information: 1. Some studies suggest that it helps to reduce obesity, helps in delaying aging, and helps to reduce some diseases.
2. In humans, depending upon the level of physical activity, fasting typically results in a greater decrease in serum glucose and depletion of the hepatic glycogen, accompanied by a switch to a metabolic mode in which non-hepatic glucose, fat-derived ketone bodies, and free fatty acids are used as energy sources.
3. Most tissues can utilize fatty acids for energy, during prolonged periods of fasting, the brain relies on the ketone bodies β-hydroxybutyrate and acetoacetate in addition to glucose for energy consumption.

So, the answer is B. Less urea in his urine.

Note: Ornithine cycle helps in the production of urea.
In the ornithine cycle, ammonia is converted to urea, and urea is excreted out from the body.