Yep, I know how it is. You don't have diabetes, so you're going to blow off thinking about blood sugar faster than a flight attendant blows off a flirty coach passenger. And that would be a mistake. You may think your blood sugar—which is a substance that can damage your arteries if levels are too high—is normal, but most blood sugar levels are recorded when you've fasted. Having "normal" levels (under 100 mg/dl) for fasting and for after meals (under 140 mg/dl) are important. Why? Because there's a good chance that even with normal blood sugar levels, your blood sugar may rise significantly throughout the day as you eat.