Insulin is a hormone produced in your pancreas. Its best known effect is to lower blood sugar by driving sugar and other nutrients into cells, especially muscle cells. Your muscles need insulin to help them produce energy and recover from the effects of exercise. Inflammation interferes with the effect of insulin on your muscles. Just as inflammation causes leptin resistance, it is a major cause of INSULIN RESISTANCE. With insulin resistance, your muscles are not fully responsive to insulin, so they don’t efficiently burn the sugar that circulates in your blood. As a result, your blood sugar starts to rise. Your pancreas responds by releasing more insulin. When the degree of insulin resistance outpaces the ability of your pancreas to produce more insulin, diabetes occurs. Whether or not you actually develop diabetes, high levels of circulating insulin can have seriously negative effects. There are some actions of insulin that occur outside of muscle and are not impaired during insulin resistance. As insulin levels increase, these effects of insulin are felt. High insulin levels make your kidneys retain fluid, raising your blood pressure and creating that feeling of being bloated and swollen. High insulin levels prevent cells from breaking down fat, making it harder to lose weight through dieting. Insulin also turns on genes that produce a number of mediators of inflammation, so with high insulin, as with high leptin, the level of inflammation in your body increases.
Your brain and your adrenal glands are attuned to the level of inflammation in your body. As inflammation increases, your brain sends a signal to your adrenal glands to produce more of a hormone called cortisol. You may be familiar with cortisone, a drug used to relieve symptoms of inflammation like itching, redness or pain. Cortisol is the natural equivalent of the drug, made in your own adrenal glands in response to stress. Cortisol naturally combats inflammation, but at a high price. Cortisol increases the amount of belly fat. It also causes fluid retention, muscle weakness, memory loss, high blood pressure, and further raises your blood sugar. The increase in blood sugar then stimulates a further increase in insulin.