Certain industrial, pharmaceutical and dietary compounds can function as obesogens – substances that can alter metabolism and predispose people to gain weight. These compounds increase the number of fat cells, or adipocytes, in the body while increasing the capacity for fat storage in cells that already exist. Obesogens also are capable of changing metabolic rate, affecting the hormonal control of appetite and satiety (the sensation of fullness) and shifting the energy balance to promote storage of calories. Most obesogens are also endocrine disruptors – substances which interfere with the endocrine system and cause unwanted developmental, neurological and immune effects. Endocrine disruptors can cause problems by mimicking natural hormones in the body, binding to cell receptors and blocking the way natural hormones are made or controlled.
The term “obesogens” was originally coined by Bruce Blumberg, a biology professor at the University of California, who in 2006 discovered that tin-based compounds known as organotins predisposed laboratory animals to gain weight.
The list of known obesogens includes specific pharmaceutical medications, pesticides, PCBs (polychlorinated biphenyls) and plasticizers. Such chemicals are found in everyday items, such as food packaging, detergents, cosmetics and in food we eat.
Examples are atrazine, a common weed-killer, and DDE (a breakdown product of DDT) both linked to insulin resistance in animals and increased body mass in children. The diabetes drug Avandia (rosiglitazone) has been linked to weight gain in humans and animals. Common plasticizers such as BPA (bisphenol A) and PVC plastic products contain endocrine disruptors known as phalates, which are linked to obesity in humans. BPA found in plastic water bottles has been shown in animal studies to increase the size of fat cells, worsen glucose intolerance and increase abdominal fat.