Years ago, John Bantle, MD, gave brownies to people with diabetes. Brownies made with real sugar. And their blood glucose levels…did not skyrocket.

Bantle and his colleagues were comparing two meal plans. Both plans had the same amount of carbohydrate. In one, much of the carb was from sugar. In the other, the carb came mainly from starches. Participants ate one meal plan for 28 days and then switched to the other.

Participants’ blood glucose levels were essentially the same when they ate the high-sugar meals as when they ate the high-starch meals. Conclusion: Sugar is just another carbohydrate. It’s the amount of carb, not the source, that determines blood glucose levels.

That was 15 years ago. Yet today, people who have diabetes still hear, “You can’t eat that. It has sugar.”

Will the myth ever die?

“Old ideas that are wrong do die,” says Bantle, a professor of medicine at the University of Minnesota, Minneapolis. “It just takes them a long time. People spent 60 years drumming it into people with diabetes. It was in all the textbooks. And if your blood sugar is high, intuitively it makes sense that you shouldn’t eat sugar.”

But starch is a string of glucose molecules. When people know that, they can see that starches will raise blood glucose levels just as sugar will.

“A lot of people who are up-to-date in diabetes consider this old news,” says Bantle. “But if you go to the primary care arena, I think they’re much less aware. I was talking to some medical students last week, and they thought sugar was a bad thing. But they’re just a product of their culture. As I talk to patients, some people seem to know it, and for others it comes as a surprise.”

For years, the American Diabetes Association’s Nutrition Recommendations have included their version of  “Sugar is just another carb.” In the 2008 position statement, the wording is: “Sucrose-containing foods can be substituted for other carbohydrates in the meal plan or, if added to the meal plan, covered with insulin or other glucose-lowering medications. Care should be taken to avoid excess energy intake.”

Bantle puts it in real-world terms: “Foods that contain sugar don’t produce a greater rise in blood glucose than bread, rice, and potatoes, if the calories are the same. If you add dessert to a meal, increasing the amount of carbohydrate, your blood sugar will be higher. But you’d have the same effect if you had a double helping of mashed potatoes or an extra roll.”

Readers, what has been your experience with sugars versus starches? Does your meter tell you that a dinner roll is the same as a piece of cake?

Marie McCarren is the author of A Field Guide to Type 2 Diabetes and ADA Guide to Insulin & Type 2 Diabetes.