Having high body fat does not necessarily cause a change in the actual chemical shape, or structure, of your hormones. But it can have negative effects on the levels of hormones circulating in your blood; it also alters the characteristics of target cells specially designed to receive them. According to University of New Mexico, excess fat produces hormone-like inflammatory proteins called cytokines; these may play a role in the development of diabetes, obesity and heart problems. Your doctor can help you develop a diet and exercise plan to maintain a healthy weight and reduce your risk of serious disease.
Endocrine System
Your endocrine system -- made up of hormones and the glands that produce and secrete them -- regulates a vast array of body functions, including behavior, mood, appetite, sexual function and growth. The pituitary gland, often called the system's "master gland," produces and secretes a variety of key hormones, including growth hormone, thyroid hormones and endorphins. Many of the workings of the pituitary are orchestrated and controlled by the hypothalamus, an area of specialized cells in your brain. Other hormones include melatonin, which controls the sleep cycle, the sex hormones estrogen and progesterone, and insulin and glucagon, which stabilize blood sugar levels. Excessive or insufficient levels of hormones can cause a variety of health problems, among them Cushing's syndrome and diabetes. In addition to having excessive body fat, other factors that affect hormone levels are stress, disease and changes in fluid and mineral levels.
High Body Fat and Insulin Target Cells
According to a scientific review published in 2008 in "Diabetes Care," obese subjects have high levels of free fatty acids, which stimulate the release of insulin. Hyperinsulemia, or excessive levels of insulin in the blood, is closely linked with high body fat. Hyperinsulinemia can lead to insulin resistance, in turn increasing your risk of type 2 diabetes. In an early clinical study of seven obese patients conducted by the National Institutes of Health in 1976, researchers found that high levels of insulin in the blood caused fewer specialized insulin receptors to appear on cell surfaces. More than three decades later, the review published in "Diabetes Care" supported this study, with the authors reporting that rats given increasing doses of insulin had fewer receptors on their target cells.
Adiponectin and Leptin
Excess fat tissue, or adipose tissue, actually functions as an additional endocrine organ, sending signals to the brain and promoting the release of hormones and chemicals in a manner similar to that of endocrine glands. In addition to producing inflammatory cytokines, excess fat also affects levels of hormones that control appetite and weight. People with high body fat and insulin resistance tend to have lower levels of adiponectin, a beneficial hormone that breaks down fat and promotes insulin sensitivity. Excess fat also affects your body's production of leptin, a hormone that controls appetite. When fat cells get smaller in size, leptin levels decrease, triggering an increase in appetite. When fat cells get bigger, leptin levels increase, signaling the body to eat less. Research is currently being conducted on leptin's possible use for weight control.
Metabolic Syndrome
High body fat, particularly around the waist, is associated with metabolic syndrome, a condition with a constellation of symptoms that include insulin resistance, glucose intolerance, high blood pressure, abnormal cholesterol levels and high blood triglycerides. According to MayoClinic.com, metabolic syndrome increases your risk of serious health problems such as diabetes, heart disease and stroke. A waist circumference of over 40 inches for men and 35 inches for women is one of the diagnostic criteria for metabolic syndrome.
References
- Diabetes Care; Insulin Resistance and Hyperinsulinemia: Is Hyperinsulinemia the Cart or the Horse?
- Canadian Medical Association Journal; Pathophysiologic Changes in Obesity, 1978
- National Institutes of Health: Fluctuations in the Affinity and Concentration of Insulin Receptors
- KidsHealth: Endocrine System
- MayoClinic.com: Metabolic Syndrome: Symptoms
- University of New Mexico: Growing Problem of Obesity
- Arizona State University: Department of Chemistry and Biochemistry
