I have struggled to understand all these numbers, as mine go up at the drop of a hat. I have purchased the book diabetics 101, which when you get thru all of the stats, states that readings can also depend on whether you have emptied your tummy recently, as well as your diet. So that's why I couldn't understand why even if I ate the same food etc, the readings would be higher or lower. Also if I have a really upset tummy, readings go right down, obvious really. I went shopping the other day for 4 hour's without food or drink, started feeling a bit rough, so when I got home tested the lowest for years- 7.0. To sum up I've found as well as low carb's etc, fasting a few hours and going to loo work's wonder's, for me anyway.