why is grapefruit a good diet food?

Answer 1

It is not. That is a fad that had come and gone.

Answer 2

Actually grapefruit is a good diet food because the acids speed up the metabolism thereby burning off the calories of other foods you have eaten.

Answer 3

grapefruit diet appears to reduce insulin levels and thus, affects blood sugar regulation. Bear in mind that the pancreas secretes insulin in response to the amount of carbohydrate ingested (also affected by the glycemic index and glycemic load of a food or meal) and that grapefruit by itself is considered by some to be low glycemic.