Doc: Glucose tolerance test best for diabetes diagnosis

Keith Roach
To Your Health

Dear Dr. Roach: I am a 67-year-old man, in excellent health, who takes no medications and is very proactive about maintaining good health: I do fitness three days a week, yoga three days a week and I fast on Saturdays. On Sundays, I take weight, blood pressure and blood sugar readings.

I am writing to you about my blood sugar readings. My fasting blood sugar readings are uniformly in the 90s, probably averaging 93. A friend suggested that I also should check my blood sugar reading one hour after eating. I did that, and it was a shocking 173. I have no symptoms or complaints concerning anything that might be related to blood sugar.

Is this normal? Should I be checking into something, like diet, as a result of this?


Dear L.A.: This is not normal. If confirmed by a second test, you meet the diagnosis of diabetes, almost certainly Type 2. In early diabetes, the only defect is the inability to respond to a sugar load. That’s the reason a glucose tolerance test remains the best test to make the diagnosis of diabetes, even though it can be diagnosed by high fasting blood sugars (eventually), or by the A1c level (a measurement of overall blood glucose level in the past several weeks). You need to see your regular doctor or a diabetes specialist.

I am not yet a proponent of intermittent fasting (I am conservative, and won’t recommend a drastic change in lifestyle without good evidence).

In people with diabetes, I think this idea is particularly bad. Regular meals are important, and their composition is critical. In early diabetes, it’s the sugar load that the body has a hard time with. Since processed carbohydrates (such as white bread) are rapidly converted to sugar, the key is to have meals with protein and healthy fat, and to make the carbohydrates you eat come more from vegetables.

I recommend you also see a registered dietitian nutritionist, who can help you with personalized information.

While you may need medication, at this point a very careful diet may be all that is needed to lower your blood sugars after eating and to prevent progression.

In most people, weight loss also can reverse the resistance to insulin that is the hallmark of Type 2 diabetes.

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