Most adult onset diabetes or type 2 can be cotrolled wiht diet as long as the BG and teh A1c are not that high. Slightly elevated in the 120-130 fasting to about 180 can be regulated with a very adjusted diet.
However in some cases AOD has to be helped in later stages with some sort of oral medication. IN later stages when these fail insulin will ahve to be given. So when these people proved well into their diabetes with diet alone, this is nto the norm. But the first stages of AOD.