What is a healthy blood sugar level?

Having a high blood sugar level can mean you have diabetes. Watch as Dr. Oz explains what a healthy reading is in this video.

You should keep your blood-sugar levels to less than 100 mg/dL.

The excess sugar in the blood that's caused by diabetes damages the arteries by inactivating a specific substance (phosphokinase, to get technical) that makes it possible for your arteries to smoothly dilate and contract. Without that substance, the risk of holes or cracks appearing at junctions in the arterial walls increases dramatically.

So all of us, not just diabetics, really want to avoid foods that are high in simple sugars and saturated and trans fats like jelly doughnuts. Also steer clear of foods and drinks with high fructose corn syrup.

A healthy blood sugar level is between 70 and 130 milligrams per deciliter (mg/dL) before meals and less than 180 mg/dL one to two hours after the start of a meal, according to the American Diabetes Association. Three tests are commonly used to measure blood sugar levels. A random plasma glucose test is a blood test that is done at any time of day. It may indicate you have diabetes if your blood glucose level is 200 mg/dL or higher. A fasting plasma glucose (FPG) test is often done first thing in the morning, after you have not eaten for at least eight hours. You may be diagnosed with prediabetes (at risk for diabetes) if your blood glucose level is 100 to 125 mg/dL on the FPG test, and you may have diabetes if your level is 126 mg/dL or higher.

The third test, called the oral glucose tolerance test, (OGTT) is also done after you have fasted for eight hours. You'll consume a glucose-containing beverage, and your blood will be taken two hours later. If your blood glucose level measures 200 mg/dL or higher on two different OGTTs, you may be diagnosed with diabetes. If it measures 140 to 199 on an OGTT, you may have prediabetes.