Insulin is a hormone secreted by the pancreas, a gland located behind the stomach that controls blood sugar. Carbohydrates are broken down during digestion to the simplest sugar, glucose. Insulin regulates how much glucose stays in the blood and how much goes into the cells. If insulin levels are too high or too low, blood sugar levels shift erratically. High blood sugar levels (hperglycemia) lead to diabetes. Low blood sugar (hypoglycemia) causes muscle weakness, headaches, sweating, tremors, and mental confusion. The brain is especially sensitive to sudden drops in glucose. If hypoglycemia is severe, seizures and even death can occur.
Many people develop a condition where insulin is blocked from carrying glucose into the cells. We say that the cells have become “insulin resistant”. This occurs mainly in the liver, muscle and fat cells. The pancreas responds by producing more and more insulin to overcome this resistance. Abnormally high insulin levels lead to abdominal weight gain, problems with cholesterol and triglycerides, fatty liver, high blood pressure, gout and polycystic ovaries. As insulin resistance worsens, the pancreas cannot keep up the demand. Blood glucose levels creep up and diabetes develops.
At least 75 percent of overweight Americans have some degree of insulin resistance. As you become more overweight, insulin resistance worsens. By the same token, the more weight you lose the less insulin resistant you become.