Glycemic Index Better Than Carbs for Blood Sugar?

If you're living with diabetes, you know that keeping track of how many grams of carbohydrates you eat—and deciding how much insulin to take to "cover" those carbs—is an important part of managing your blood sugar.  But a new study is questioning whether a more effective way to regulate blood sugar would be to focus on a food's glycemic load instead.

"The glycemic load refers to the speed in which what you eat becomes sugar in the body," explains Spyros Mezitis, MD, of Lenox Hill Hospital in New York City. "It can be important for blood sugar control because if you can't control the sugar surge in the body, cardiovascular problems can occur over time."

Foods are rated on a glycemic index, with those that are lower on the index causing blood sugar to rise more slowly and those higher on the index causing a more rapid rise of blood sugar.

For the new study that challenges carb counting as the best method for keeping blood sugar close to normal, Jiansong Bao and his colleagues at the University of Sydney in Australia looked at finger-prick blood samples of 10 healthy volunteers. The study participants consumed 120 different varieties of food, each with the same number of calories. The study researchers also asked two groups of volunteers to consume meals that contained assorted staples from the typical Western diet. Thus they ate eggs, steak, bread, and cereal. The result? The glycemic load consistently won out over carb counting as a predictor of both blood sugar and insulin rise.

"It suggests that the methods used to assess carbs in persons with type 1 diabetes might benefit from some rethinking," University of Washington diabetes expert Edward J. Boyko, MD, MPH, told Reuters. Boyko, who was not involved with the University of Sydney study, also commented that so far, it's unclear if the study findings mean the same thing for people who aren't necessarily healthy.

But for diabetics, carb counting is still key for maintaining good blood sugar control,  says Robyn Webb, MS, LN, food editor at Diabetes Forecast magazine. It's important to record both the type and the amount of carbohydrates you consume, she says. "You'll be able to see how best to manage your diet when you see how the carbs affect your body," she says. "I see carb counting as a good clue as to what is working and what's not working."

Choosing foods that are low on the glycemic index can certainly make a difference, says Caroline Bohl, MS, RD, CDE, of the Naomi Berrie Diabetes Center at Columbia University Medical Center in New York City. "But you still need to count carbs and factor them in," she says. Also, Bohl points out, foods affect each individual's blood sugar differently.

"How the blood sugar is affected depends on a person's metabolism," Bohl explains. "I tell people to look at the glycemic index, but then see how a food affects their own blood sugar." Generally, Bohl, says, counting carbs and choosing high-quality, high-fiber food is essential.

Familiarizing yourself with the glycemic index of various foods can be very helpful, says Mezitis. "But it's not only how much of a carbohydrate you eat, but also the type of carbohydrate you eat that's important," he says.



Joelving, Frederik. "Study challenges 'carb counting' in diabetes." 11 March 2011. Reuters.