The research, published in the American Journal of Clinical Nutrition, challenges the idea that weight loss is necessarily a crucial factor for reducing risk of type-2 diabetes.
The researchers, from the University of Alabama at Birmingham (UAB) provided 69 healthy overweight individuals with one of two calorically identical diets for eight weeks – either a reduced carbohydrate, higher fat diet (43 percent carbohydrate, 39 percent fat), or a standard diet of 55 percent carbohydrate and 27 percent fat.
They found that after 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,” said UAB department of nutrition professor and lead author of the study Barbara Gower.
Quality not quantity
The researchers took into account any minor fluctuations in weight during the study, and provided participants with the amount of food necessary to maintain weight, they said.
Gower said: “People find it hard to lose weight. What is important about our study is that the results suggest that attention to diet quality, not quantity, can make a difference in risk for type 2 diabetes.”
The proportion of the population diagnosed as diabetic has been rising rapidly in recent years. According to the International Diabetes Federation, 8.5 percent of the European population now has diabetes, and that figure is expected to rise to 10 percent by 2030. In North America and the Caribbean, the figure is even higher – 11.7 percent of the population in the region is diabetic, expected to rise to 13.6 percent by 2030.
Particular significance for blacks
The risk of developing type-2 diabetes is higher for black people, and this latest research found that results for African-American study participants on the lower fat diet were more significant that for European-Americans. Gower said that a stronger difference in insulin secretion for blacks on the lower fat diet, compared to the lower carb group, could indicate that diet composition is an important factor for mitigating diabetes risk in this population in particular.
Study co-author and UAB dietician Laura Lee Goree said that the 39 percent fat or 27 percent fat proportions of the diets used in the study “were actually fairly moderate.”
Current dietary advice in the US recommends an ideal proportion of fat intake to be 20 to 35 percent of daily calories, with less than 7 percent of total calories from saturated fat.
“Individuals at risk for diabetes easily could adopt the lower fat diet we employed,” said Goree. “Our findings indicate that the lower-fat diet might reduce the risk of diabetes or slow the progression of the disease.”
Source: American Journal of Clinical Nutrition
Published online May 18 ahead of print
“Dietary macronutrient composition affects β cell responsiveness but not insulin sensitivity”
Authors: Laura Lee Goree, Paula Chandler-Laney, Amy C Ellis, Krista Casazza, Wesley M Granger, and Barbara A Gower