After nine weeks of intervention, participants in the first group lost, on average, about 2.3 kilograms (5.1 pounds), decreased their waist circumference by 2.9 centimeters (1.1 inches), reduced their body mass index, a ratio of weight to height, by almost a point and lowered their blood glucose concentration after eating by almost 18 milligrams per deciliter. Experts suggest blood glucose after eating should remain below 180 milligrams per deciliter in people with diabetes.

Another nine weeks later, even with no additional intervention, these participants had maintained those health benefits, with the exception of an average slight gain in waist circumference among women.

The participants who waited nine weeks for the intervention recorded similar health improvements after they attended the education sessions.

But Miller noted that while they waited, this group also gained weight and recorded expansions of their waists - yet another sign that education can't start soon enough for many patients with diabetes.

"They had a trajectory of change that was getting worse," she said. "People with diabetes do need continued support to sustain optimal glycemic control because the disease progresses as they live longer."

Based on self-reports of food choices, the study showed that participants' fiber intake improved and they ate less fat. And they did not restrict carbohydrates, but instead made different carbohydrate choices.

"We were not putting people on a strict diet. They consumed the same amount of carbohydrate that they normally would, but selected lower glycemic-index foods within that carbohydrate allotment," Miller said. "That addresses another controversy in nutrition. People with diabetes do not have to go on a low-carb diet, which typically is accompanied by a high intake of fat.

"What these participants ate was closer to the dietary guidelines generally recommend for Americans, with less than 30 percent of calories coming from fat. The quantity of carbohydrate does matter to some extent, but the type of carbohydrate makes a big difference."

Source: Ohio State University