The global obesity epidemic is getting worse, especially among children, with rates of obesity rising over the past decade and shifting to earlier ages. In the US, roughly 40% of today’s high school students were overweight by the time they started high school. Globally, the incidence of obesity has tripled since the 1970s, with fully one billion people expected to be obese by 2030. The consequences are grave, as obesity correlates closely with high blood pressure, diabetes, heart disease and other serious health problems. Despite the magnitude of the problem, there is still no consensus on the cause, although scientists do recognize many contributing factors, including genetics, stress, viruses and changes in sleeping habits. Of course, the popularity of heavily processed foods — high in sugar, salt and fat — has also played a role, especially in Western nations, where people on average consume more calories per day now than 50 years ago. Even so, recent reviews of the science conclude that much of the huge rise in obesity globally over the past four decades remains unexplained.
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.