"We found that exposure to a high-fat diet before birth modifies gene expression in the livers of offspring so they are more likely to overproduce glucose, which can cause early insulin resistance and diabetes," said Yuan-Xiang Pan, a professor of nutrition. The high-fat diet that caused these changes was a typical Western diet that contained 45 percent fat, which is not at all unusual, he said.

     In the study, Pan and doctoral student Rita Strakovsky fed obesity-resistant rats either a high-fat or a control diet from the first day of gestation. Because the animals were not obese before the study began, the scientists were able to determine that diet alone had produced these effects.

     "At birth, offspring in the high-fat group had blood sugar levels that were twice as high as those in the control group, even though their mothers had normal levels," Strakovsky said.