Starting in 2010, researchers in Toronto, Canada, enrolled 121 patients with Type II diabetes and tested their blood sugar, blood pressure, cholesterol levels, and more. Roughly half of the study participants were randomly selected to add a cup of legumes per day to their diet. The other half were told to try to eat morewhole-wheat products.
While the study was funded by legume farmers, the results confirm previous findings that showed changes in diet can reduce diabetes symptoms and protect patients from more severe complications of the disease. In 2002, a large government trial found that overweight people on the verge of developing diabetes could dramatically lower their risk of the disease by changing their diet and exercising more. And in 2008, David Jenkins, one of the current study’s lead authors, published similar results that demonstrated the strong benefits of a diet high in vegetables, fruit, nuts, flaxseed, and, yes, legumes.
Others aren’t convinced about the power of GI, however. In an article accompanying Jenkins’ current paper, nutrition consultant Marion Franz argues that some recent studies actually find no impact of glycemic index on diabetics’ blood sugar — and, Franz says, the very definition of glycemic index is “confusing.”
The GI measures the relative area under the postprandial glucose curve of 50 g of digestible carbohydrates compared with 50 g of a standard food, either glucose or white bread. It does not measure how quickly foods are digested and absorbed into the blood stream as claimed by diet books (and many health professionals). […] Although there is a modest difference in the glucose peak from […] high- vs low-GI carbohydrates, the peak occurs at similar times. Furthermore, the mean glucose and insulin responses to a high-GI diet vs a low-GI diet are parallel. There is no quick or sharp glucose or insulin peak response to the high-GI meals.
That’s not to say that legumes shouldn’t be part of a healthy diet. Franz agrees that chick peas, lentils, and beans are all high in fiber and vegetable protein, and they’re not too calorie-dense. So whether or not legumes are the answer to controlling diabetes, at least on some level, the experts do agree on the big picture: eat a healthy diet; it matters.