NCPA - National Center for Policy Analysis

Are Plastics Making Us Fat?

August 16, 2010

Health gurus claim chemicals -- not calories -- are the cause of obesity.  They are wrong, says Allysia Finley, assistant editor of 

Antichemical crusaders argue that the rise in obesity has coincided with the increase in use of the ubiquitous chemicals phthalates and bisphenol A (BPA): 

  • Phthalates can be found in medical tubing, make-up and PVC piping.
  • BPA is often present in baby bottles and food containers. These chemicals have been widespread for over 50 years and obesity did not start surging until about 1980. 

The crusaders also point to some rodent and in vitro studies that suggest exposure to plastics during infancy and gestation can signal the body to turn precursor cells into fat cells, which may predispose people to pile on the pounds later in life. 

However, biologist Randy Seeley at the Endrocrinology Department of the University Of Cincinnati College Of Medicine is skeptical.   He says the current data have "a lot of weaknesses" and that "the work has not been done very well." 

  • After reviewing the studies, he performed a more rigorous experiment exposing female mice to low doses of BPA.
  • While their pups were born bigger and grew faster at an early age, the effect faded over time such that as adults they were no fatter than the controls.  

Still, he says, it's "very hard to prove something is safe" since there are countless doses and responses that could be tested.   And studies on rodents can't necessarily be extrapolated to humans. 

There is no doubt obesity is a public health problem, but its causes are myriad and complex.   By ringing the alarm bells based on insufficient and inconclusive evidence, environmentalists have subverted serious discussion of the issue and are on track to create another green scare, says Finley. 

Source: Allysia Finley, "Are Plastics Making Us Fat?" Wall Street Journal, August 13, 2010. 

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