Definition. The urine creatinine test measures the amount of creatinine in urine. Creatinine is a breakdown product of creatine, which is an important part of muscle. Creatinine is removed from the body entirely by the kidneys. Creatinine can also be measured by a blood test.
Ketones are the byproduct of breaking fatty acids down to be burned. Okay, it's a water fast, but we can assume that after 3 days, ketosis is acheived. About 250 grams of fat is about the maximum amount of fat that will be burned daily. I say around 250-300 grams per day.
Example: If you would like to know how many calories you need to burn one pound of fat in our example, you simply subtract the 500 calories from your baseline of 1950 calories. 1950 - 500 = 1450 calories per day to lose 1 pound of fat per week.