Aha! I have struggled with understanding this since I was diagnosed, I felt that as I'm overweight, people would just think I snacked too much in the evenings, But then, after my GP retired, my new doctor told me that my general levels were just generally too high for my body to cope with over night.
The solution for me was an additional tablet in the morning (I now take gliclacide) Whereas I know that some people want to avoid medication and go for a more natural healthy approach, this has really helped me get my levels to under 7 - when for over a year I was struggling to get under 12.