According to a study in the American Journal of Clinical Nutrition, small differences in diet—even without weight loss—may affect risk for diabetes.
In the study, 69 healthy, overweight people who did not have diabetes—but were at risk for it—were placed on diets with modest reductions in either fat or carbohydrate for eight weeks. Study participants in the lower fat group received a diet comprising 27% fat and 55% carbohydrate. The lower carb group’s diet was 39% fat and 43% carbohydrate. All food for the trial was provided by the study.
At eight weeks, the group on the lower fat diet had significantly higher insulin secretion and better glucose tolerance and tended to have higher insulin sensitivity. These improvements indicate a decreased risk for diabetes. According to the researchers, the results were independent of weight loss.
The study participants were fed exactly the amount of food required to maintain their body weight, and the researchers took into account any minor fluctuations in body weight during analyses. Thus, results from this study suggest that those trying to minimize risk for diabetes over the long term might consider limiting their daily consumption of fat at around 27% of their diet.
The findings were even stronger in African Americans, a population with an elevated risk for diabetes. African Americans on the lower fat diet showed a stronger difference in insulin secretion compared to the lower carb group, indicating that diet might be an important variable for controlling diabetes risk in that population.
The researchers concluded that further research is needed to determine if the difference between diets in carbohydrate or fat was responsible for the differences in the measures of glucose metabolism and probe the potential cause-and-effect relationship between insulin and glucose responses to the diets.