There is no debate that most obesity comes from poor diet and insufficient exercise.
But a third cause may exist. The effects on humans are yet unclear, though it has a compelling draw.
The third group of causes is known as obesogens. They are chemical compounds that disrupt normal lipid and endocrine systems. Many of these suspect chemicals are pesticides and plasticizers (chemicals added to rubbers and resins to impart flexibility, workability, or stretchability).
More than 30% of adults are obese. Scientists increasingly think that exposure to some environmental chemicals may be another, yet under-recognized factor, in the obesity epidemic.
In 2006, Grün and Blumberg coined the term obesogen, and other authors suggested that obesogens make it hard to lose weight. A flurry of ideas followed – for example, that the fungicide tolylfluanid interfered with normal insulin signaling, which in mice were found to cause weight gain. Other research suggests plasticizers, like phthalates, induce fat-cell production. Estrogen mimicking endocrine disruptors, such as BPA (bisphenol A, used in plastics and resins, may leach into food from containers coated with BPA) given to pregnant mice will cause obese offspring. Other research work implicates that obesogens activates the fatty acid receptor PPARy – this is one of the master regulators of fat-cell development. The list is long, and the chemistry is quite complex.
What we need to know is if, and how much, do obesogens effect human health? Trasande from NYU reports that white children, but not black or Hispanic children, exposed to BPA had double the incidence of obesity. Li did a study in China which produced similar results – but both studies raise the question of if these were completely true-positive observations – might there be another variable yet unknown?
One bureaucratic challenge is the EPA’s current inability to ban chemicals and do research on such matters. Efforts to change so to be able to more aggressively initiate these activities is underway.
But even as the scientific debate continues, and the continuing strong intellectual draw towards that the possibility that obesogens may contribute to obesity in humans, it’s critical that we insist that hard research be done, that there isn’t an over-simplification or over-extension of some evidence into “truths”, and that we try to reduce our exposure to chemicals that could be problematic.
But in a society inundated with processed, treated, or modified products, that will not be easy.