According to two new studies, eating foods with high glycemic index may be associated with the risk for developing type 2 diabetes in Chinese and in African-American women. While more cereal fiber in African-American women may reverse the said association.

Foods high on the glycemic index, such as rice and other simple carbohydrates, cause a rapid spike and then a drop in blood glucose, whereas high-fiber foods tend to be lower on the glycemic index and have a more gradual effect. Some evidence has linked high-glycemic index foods with the risk of developing type 2 diabetes.

Study 1: Supriya Krishnan, D.Sc. of Boston University School of Public Health, and colleagues examined data from 40,078 U.S. black women who filled out a food questionnaire in 1995.

The glycemic index and glycemic load-a measure of the amount of carbohydrates from glucose-were calculated. Every two years through 2003, the women answered follow-up questionnaires about their weight, health and other factors.

During eight years of follow-up, 1,938 participants developed type 2 diabetes. Women who ate high-glycemic index foods or a diet with a high glycemic load had a higher risk for diabetes.

However, women who ate more fiber from grains (cereal fiber) had a reduced risk; for women with a body mass index (BMI) of less than 25, women who ate about 1.5 grams of fiber per day were 59 percent less likely to develop diabetes than women who ate about 8.3 grams per day.

Study 2: Raquel Villegas, Ph.D., of Vanderbilt University Medical Center, Nashville, Tenn., and colleagues followed a group of 64,227 Chinese women for an average of five years.

During in-person interviews conducted every two years between 2000 and 2004, the researchers collected data on dietary habits, physical activity and other health-related information.

During the study, 1,608 of the women developed diabetes. Women who consumed more carbohydrates overall were more likely to develop diabetes-when they were split into five groups based on carbohydrate intake, those in the group consuming the most (about 337.6 grams per day) had a 28 percent higher risk than those in the group consuming the least (about 263.5 grams per day).

Women who ate diets with a higher glycemic index and who ate more staples such as bread, noodles and rice specifically also had an increased risk. Women who ate 300 grams or more of rice per day were 78 percent more likely to develop diabetes than those who ate less than 200 grams per day.

Find more details from the JAMA and Archives Journal.