To address these questions, we have used a previously validated rat model of IUGR for early catch up growth and later development of impaired glucose homeostasis and excess adiposity [22] to investigate the short term and long term consequences of milk protein type (casein vs. whey) for a few weeks during the post suckling period (referred to hereafter as the weaning period, which corresponds to the complementary feeding period in the infant) on markers of glucose and insulin metabolism and body composition. Here, INS is linked to fetal growth restriction.