Here's a scenario I get all the time with (type II) patients:

- So, how does your sugar run at home?

- Good

- What's good?

- Sometimes 130, sometimes 100...

- Wow, that is good- what time do you check it?

- First thing in the morning

- Why do you check it then?

- My doc told me too

(sigh)

What's wrong with this picture?  Well, hopefully nothing, but the fact is that there are plenty of diabetic patients out there who do not have good blood sugar control, even though their fasting sugar is ok.  Why is this?

Well, common sense would say that of course sugar control will be best when you haven't eaten anything.   But the real answer has to do with the progression of diabetes.  Type II diabetes progresses from insulin resistance.  And insulin resistance simply means that when you eat a meal, your insulin doesn't clear all the nutrients/sugar out of your blood.  So with insulin resistance, blood sugar will be high after a meal, but normal when fasting.

Indeed, if a diabetic has a normal fasting glucose, this is a good sign- it means that the diabetes is in an early stage, and that treatment to lower the after-meal glucose can slow its progression.  Unfortunately, diabetics with high fasting glucose will likely need insulin sooner rather than later.

So the point is, even with great fasting control, after-meal glucose needs to be controlled to maintain a healthy body.  And you need to know when you are running high in order to effect healthy changes (when you should eat less carbs, exercise, take medicine, etc.). 

So then why do docs say to check sugar 'first thing in the morning'?.  Well, type Is and diabetics on insulin may check fasting sugar to make sure it's not too low, or to calibrate an optimal insulin dose.  But for type IIs, who check diligently every morning and have good control, I say- get some more sleep, and check your sugar 2 hours after you eat your largest meal of the day.  Then you'll see how good your glucose control is.