The aim of the work was to determine the effect of body fat change on risk of diabetes in normal glucose tolerance (NGT) population. A total of 1,857 NGT subjects were included and followed up for an average period of 44.57 months. Body fat percentage (BF%) was measured by bioelectrical impedance analysis. Subjects were grouped based on the BF% and/or body mass index (BMI) state. Among all subjects, 28 developed diabetes after follow-up. Compared with subjects with stable normal BF% (control), subjects who became obesity at follow-up were defects in insulin secretion and had a higher risk of developing diabetes (7.102, 95% confidence intervals [CI] 1.740-28.993), while no difference in diabetic risk could be viewed between subjects with abnormal BF% at baseline but normal at the end of follow-up and control subjects after adjustment of confounding factors. Moreover, compared with those keeping normal BF% and BMI both at baseline and follow-up, subjects who had normal BMI at baseline and follow-up, but abnormal BF% at baseline or/and follow-up still had a higher risk to develop diabetes (4.790, 95% CI 1.061-21.621), while those with normal BF% at baseline and follow-up, but abnormal BMI at baseline or/and follow-up had not. Subjects from normal BF% at baseline to obese at follow-up are associated with an increased risk of diabetes. Maintaining normal body fat is more relevant than BMI in preventing diabetes. © 2017 IUBMB Life, 69(12):947-955, 2017.