Figure 1: Insulin resistance – imbalanced usage of glucose and free fatty acid. Upon diet, glucose level increase in the blood, which sensitize pancreatic β cells to secret insulin. Insulin promotes glucose absorption for energy production and storage as glycogen in liver and skeletal muscle. In the situation of overweight and obesity, larger amount of free fatty acid is released from adipocytes into circulation. They replace glucose to be uptaken by liver and skeletal muscle for energy production and stored as triglyceride. Moreover, free fatty acid interferes with insulin action on liver and skeletal muscle for glucose usage. The sustained high level of glucose continues to stimulate β cells for insulin production to compensate insulin resistance. As insulin resistance progresses, β cells fail in insulin production due to exhaustion and dysfunction.