Prior to the development of whole body insulin resistance, downregulation of key insulin signalling proteins such as insulin receptor substrate-1 (IRS1), glucose transporter type 4 (GLUT4), and the p110β catalytic subunit and p85α regulatory subunit of phosphatidylinositol 3-kinase (PI3K) have been observed in skeletal muscle and WAT of both LBW men and LP offspring rats [2, 4–6]. This evidence concerns the gene IRS1 and Insulin resistance.