Measuring fasting blood glucose on waking in the morning

[Cetus]

I want to measure my fasting blood glucose and figured that taking a reading after getting (but before food or medication) is a good time.

However I have read that various overnight effects can cause a "dawn phenomenon" in which blood glucose is artificially raised.

How long should I wait after waking and getting up to get a decent fasting reading?

[Cetus]

I didn't realise food eaten the day before would still have an effect on morning glucose levels. I must eat less at night and see if it makes a difference.