Consistent with these observations, WD-fed rats showed an overall impaired glucose tolerance at 14 and 20 weeks of age (P = 0.000), as compared with the LF-fed rats (Fig. 6C–E), and at 8, 14 and 20 weeks of age, their rise in insulin levels during the first 30 minutes of OGTTs was higher (P = 0.000) (Fig. 6F–H). Here, INS is linked to Impaired glucose tolerance.