"Carbohydrates are the body's preferred fuel and should make up at least half of your daily calories."

I get so tired of hearing this. It is misleading, inaccurate, and full of predudice and bias. Which is what dieticians specialize in. Especially those who push high-starch, high-sugar diets.

1. First, NO ONE can use 'carbohydrates' as fuel. You can use glucose, and perhaps some fructose. Period.

2. Why do they say glucose is the 'preferred' fuel? The body doesn't 'prefer' glucose, it simply uses it BEFORE other available fuels -- mainly because glucose is a troublesome, volatile and potentially harmful substance. The body can't tolerate high blood glucose -- so it quickly burns it off, OR stores it as glycogen or fat. So sure, if you eat HALF your calories as sugar (or starch, or whole grains) your body will be FORCED to burn up that glucose or suffer dangerously high blood sugars. It's not that your body PREFERS glucose. It has to get RID of it.

3. Actually, your body will burn alcohol BEFORE even glucose. Does this mean alcohol is the 'preferred' fuel? No. It's just means blood alcohol is troublesome. Better metabolize it fast and get rid of it.

4. If glucose is the 'PREFERRED" fuel, why does the body store MOST of its excess energy as fat? (Which is about 45% saturated fat, by the way.) Seems to me that the body 'prefers' to run on fat.

5. If glucose is the 'PREFERRED' fuel, how did humans survive for a half million years before they 'invented' corn or wheat?