Individuals exhibit higher blood glucose levels in the evening or late night compared to the morning after a glucose challenge.

“In fact, this has been experimentally shown almost half a century ago. In '70s and '80s, there was this talk about evening diabetics. So that means go in the morning to a clinic and get a bolus of glucose, and then after 90 minutes, you measure your blood sugar level, it may come down to normal level. But the same person, if he or she goes to the clinic in the evening or late night, gets the same bolus of glucose, and after 90 minutes the blood glucose may remain at a high level which would qualify him or her to be diabetic.”