|MadSci Network: Anatomy|
This question sounds a lot like a homework question. Can you find the answer in your own text? If not, here's what Guyton's Textbook of Medical Physiology will tell you: starvation causes the body's fat cells to release lipids into the circulation. They are degraded into small molecules of acetate in the liver; the liver forms acetoacetate from them and releases them into the bloodstream as nutrients for tissues. Since acetoacetate is a keto acid, this condition results in "ketosis" high levels of ketones in the blood and urine. A high sugar diet would not normally affect the urine unless you are diabetic, and cannot metabolize sugar. In diabetes, glucose levels are elevated in the blood and urine; also, since glucose cannot be used as a nutrient by muscles, fat is converted to acetoacetate once again, leading to ketone bodies in the urine.
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