You are likely already well aware that the obesity rate is sky high—two-thirds of Americans are overweight or obese. That’s over 65 percent. It is becoming clear that there is to more to the equation than simply calories in/calories out. There are a number of factors that are contributing to the expanding waistline of this country, one of which is our exposure to toxins known as obesogens.

Obesogens—a term coined by Bruce Blumberg, a biology professor at the University of California, Irvine in 2006—are dietary, pharmaceutical, or industrial compounds that alter metabolic processes and predispose some people to gain weight.

Many scientists are concerned about the estrogenic effects of these toxins. Certain obesogens are known as xenoestrogens—they exhibit estrogen function in the body, which interferes with normal hormone function. In a recent study published in the Public Library of Sciences One journal, researchers proposed the estrogen hypothesis of obesity, in which they suggest that obesity, particularly among men, is linked to the increase of xenoestrogen exposure from two main sources—soy food products and polyvinyl chloride (PVC) piping.

Maciej Henneberg, PhD, DSc, one of the authors, states, “Exposure to estrogen is known to cause weight gain, primarily through thyroid inhibition and modulation of the hypothalamus. Soy products contain xenoestrogens, and we are concerned that in societies with a high dietary saturation of soy, such as the United States, this could be working to ‘feminize’ the males.”

Usually, women gain weight more readily than men, but in Western countries men gain weight at an almost equal rate as women. The researchers believe this excess estrogen exposure is to blame.

“Another well-established source of xenoestrogen is polyvinyl chloride, known as PVC. This product is in prominent use in most wealthy countries, from plastic medical devices to piping for our water supplies.”

Did you ever think the soybean or vegetable oil you cook with, the plastic containers you eat from, or the PVC pipe carrying your tap water could be making you fat? Probably not. You won’t need to eliminate soy foods completely, but if you eat a lot of soy, you might want to limit your intake. In addition, avoid plastic containers with the number 3 inside the recycle symbol and use high-quality water filters on your tap water. (Reverse osmosis water filters remove the most toxins.)