Pollutants 'worsening obesity epidemic'

Chemical pollution in the environment is supersizing the global obesity epidemic, according to a major scientific review.

- Damian Carrington

The idea that "obesogen" toxins can affect how the body controls weight is not yet part of mainstream medicine. But the dozens of scientists behind the review say the evidence is now so strong that it should be. "This is critical because the current clinical management of obese patients is woefully inadequate," they said.

The most disturbing aspect of the evidence is that some chemical impacts that increase weight can be passed down through generations by changing how genes work.

Pollutants cited by the researchers as increasing obesity include bisphenol A (BPA), which is widely added to plastics, as well as some pesticides, flame retardants and air pollution.

Obesity has tripled since 1975, with more people now obese or overweight than underweight, and is increasing in every country studied. Almost 2 billion adults and 40 million under-fives are obese or overweight.

"The focus of the clinical people is on calories - if you eat more calories, you're going to be more fat," says Dr Jerrold Heindel, lead author of one of the three review papers, and formerly at the US National Institute of Environmental Health Sciences. "So they wait until you get obese, then they'll look at giving you diets, drugs, or surgery.

"If that really worked, we should see a decline in the rates of obesity," he said. "But we don't - obesity continues to rise, especially in children. The real question is, why do people eat more? The obesogenic paradigm focuses on that and provides data that indicate that these chemicals are what can do that."

The scientists say the approach offers the potential to prevent obesity by avoiding exposure to pollutants, especially in pregnant women and babies: "Prevention saves lives, while costing far less than any [treatment]."