Insulin is a hormone produced in the pancreas, and blood glucose is the source of energy for body cells. The role of insulin is to help in the uptake of glucose by body cells. Insulin resistance is a condition in which the insulin produced in the body is not utilized efficiently. Hence the uptake of glucose by the body cells is hampered leading to increased levels of glucose in the blood.
Carbohydrates in our food are broken down into glucose by our body cells. Hence, glucose levels in blood increase after meals. In response, pancreas produces more insulin to keep up with this increased demand. In people with insulin resistance, the body cells fail to respond to insulin. As blood glucose levels remain high, the beta cells in pancreas produce more and more insulin. These overworked beta cells eventually fail to keep up with the constant need for insulin, leading to diabetes.