Explain what blood sugar is all about and its implications?

Fuel: Blood sugar is the fuel your body runs on. Too low (which is vanishingly rare unless you have diabetes and are on medication) is harmful quickly. High sugar can lead to diabetes and if uncontrolled for a longer period of time, can decrease your lifespan by 1/3 and cause horrible complications. Luckily, unless you have diabetes, your body controls your glucose quite efficiently.