The Environmental Health Policy Institute, a division of the non-profit organization, Physicians for Social Responsibility (PSR) recently issued a report, "The Rise of Obesogens: Chemical Exposures and the Obesity Epidemic," in which the author states:
"Life habits, such as sedentary habits and consumption of high calorie foods, are frequently pointed to as drivers of the increase. The environment’s interaction with an individual’s genetic makeup is another potential driver—and an increasing body of evidence supports this hypothesis. One view is that the interaction between genetics and the modern environment work to intensify an individual’s propensity towards developing obesity, acting via early metabolic programming that occurs in the womb. Another is that the environment plays a different role in obesity—via exposure to chemicals in the environment, whether due to exposure in the womb, or a lifetime of exposure."
One of the principal links of toxins to obesity is from a group of chemicals classified as Endocrine Disruptors. The widely used BPA in certain hard plastic containers and canned foods as well as certain fungicides are implicated as causing obesity. This is a new area of research and remains controversial as low doses of BPA are shown to be harmless to humans. Apart from BPA, there are a list of Endocrine Disruptors identified by National Institutes of Health. These include Dioxins, PCBs, Arsenic and widely used pesticides, which can contaminate your drinking water sources.
It is always prudent to err on the side of preventing obesity by minimizing exposure to BPA by avoiding canned foods and by using stainless steel water containers rather than plastic ones.
For Endocrine Disruptors in your tap-water, there is no substitute for testing the water samples from your kitchen and shower by a certified laboratory and filter them out, if necessary. Dieting, exercise, and lifestyle changes are important in dealing with obesity and weight loss, but it is important to eliminate endocrine disrupting chemicals first.