WashPost: An emerging view among scientists is that one major overlooked component in obesity is almost certainly our environment — in particular, the pervasive presence within it of chemicals which, even at very low doses, act to disturb the normal functioning of human metabolism, upsetting the body’s ability to regulate its intake and expenditure of energy.
Some of these chemicals, known as “obesogens,” directly boost the production of specific cell types and fatty tissues associated with obesity. Unfortunately, these chemicals are used in many of the most basic products of modern life including plastic packaging, clothes and furniture, cosmetics, food additives, herbicides and pesticides.
Ten years ago the idea of chemically induced obesity was something of a fringe hypothesis, but not anymore.
“Obesogens are certainly a contributing factor to the obesity epidemic,” is what Bruce Blumberg, an expert on obesity and endocrine-disrupting chemicals from the University of California, Irvine, told me by email. “The difficulty is determining what fraction of obesity is related to chemical exposure.”
An important piece of evidence is something I pointed to in my post The Animals are Also Getting Fat namely, cats and dogs are getting fatter and so are rats and so (very importantly) are control mice fed a very standard diet. I hadn’t realized there is also some experimental evidence.
In particular, consequences of chemical exposure may not appear during the lifetime of an exposed organism but can be passed down through so-called epigenetic mechanisms to offspring even several generations away. A typical example is tributyltin or TBT, a chemical used in wood preservatives, among other things. In experiments exposing mice to low and supposedly safe levels of TBT, Blumberg and his colleagues found significantly increased fat accumulation in the next three generations.
Overall, I find the chemical story plausible–people in the past, even rich people, just didn’t get fat so easily–but my skepticism rises whenever I hear the word epigenetics.