My doctor set me these limits:
- don't drop below 4, don't raise above 9. Above 9 is bad, because it means increased risk of complications.
- try to keep BG before meals below 6 and 2 hours after below 8.
- try not to have big 'jumps' between readings - no more than 2.5 between before and after meal readings, or between days. Big differences = big risk of complications.
It took me one month after I was diagnosed to get there - with help of insulin. I now privately try to reach below 5.5 before meals and below 7 2 hours later, but I still have problems with that, especially in the morning.
With 8 before meals, you probably have more than 9 after, so it's necessary to decrease it.
And while most people here will immediately say 'low carb diet', I'm a living proof it can be done with carbs, too. I eat 150 grams of carbs every day, which is three times more than most people here. >.> It also depends on what you eat - what GI and GL it has, how you combine it with veggies, how much you drink during the day (that is in fact the hardest part of the whole diet for me - to drink 2.5-3 litres per day), how much exercise you have, your overall health and stress level... It's not a simple math, and food is just one part of it (though very important).
I eat 40 grams of carbs for three main meals, and 10 grams of carbs for snacks (though I often skip morning snack and 'second dinner'). I also try to strictly follow the drinking regime, and always drink at least 2.5 litres per day. Due to other health issues I can't go to gym, do aerobics or things like that, so for now, I at least take long walks
For example, if I eat my 40 grams of carbs for lunch in potateos (it makes 260 grams of potatoes) l get better readings after the meal if I eat a bowl of salad with it (especially leafy vegetable), drink enough, and have 15 minutes walk after it. The difference can be as much as 1 mmol.