TNF and Insulin resistance: This phenomenon may be caused by direct influx, via the portal vein, of long-chain FFAs, glycerol, and proinflammatory cytokines (e.g., tumor necrosis factor [TNF], interleukin [IL]-6, and IL-1) from the visceral and upper body fat depots, which exhibit insulin resistance and activation of hormone-sensitive lipase and adipose tissue triacylglycerol lipase [26–28].