Differential Effect of High Fat Diet on Male Mice on Energy Intake, Hormones, Cellularity and Morphology of Tissue

High fat diet contributes to obesity. Long term exposure to very high fat diet (VHFD) leads to changes, not only on body weight, hormones, food intake and metabolism but also at the cellular level affecting beta cell mass of pancreas and adipocyte cell size. Male mice fed with VHFD for 2 weeks, 3 months and 6 months showed significant increase in body weight which was proportional to saturated fat than mice fed on normal diet (ND). Food intake was lower for VHFD than ND animals indicating that it was the quality of food not the quantity that caused the increase in body weight. Male mice on VHFD showed increased plasma glucose, leptin and insulin levels within 2 weeks. Animals were hyperglycemic and developed leptin and insulin resistance within 3 months. Morphological and morphometric analysis of pancreatic and adipocytes showed increased islet size within 2 weeks and significant increase within 6 months. Parameters like changes in the hormonal level, food intake, pancreatic and adipocyte size were visible within 2 weeks but changes associated at the cellular levels like significant increase in the area were only observed after 6 months in VHFD animals. Our data therefore suggests that in diet induced obesity changes in hormonal levels and metabolism sets in much earlier than visible changes at the cellular level. All mechanism per se leptin and insulin resistance, increases in adiposity and islets size are probably a mechanism to overt diabetes. Long term studies are required to understand the cellular changes and the underlying mechanism associated with it.