Diet Soda Is Probably Not What’s Causing Childhood Obesity

Diet soda is definitely not fashionable these days. Millennials regards it as “chemicals in a can” and opt instead for artisanal soda with real cane sugar. Fine. But does fashion, plus a an observational study, add up to a sound basis for recommending what to drink in pregnancy? A pair of publications in JAMA Pediatrics suggest that the journal’s editors think it’s a reasonable proposition.

Meghan Azad and colleagues analyzed data from 3,033 pairs of mothers and infants to find an association between a mother’s self-reported consumption of artificially sweetened beverages (ASBs) and her child’s risk of obesity at one year of age. Notably, the investigators found no association between a mother’s sugar-sweetened beverage consumption and obesity risk for her child.

In a companion commentary, Mark Pereira and Matthew Gillman note that mothers who report consuming ASBs have higher BMIs before preganacy. Correction for this and other confounding factors eliminates much, but not all, of the observed risk linked to ASBs. They also note the possibility that residual confounding would render these findings meaningless. Despite this and other caveats, they go on to advise against ASBs in pregnancy, saying: “ASBs yield uncertain benefits for the mother and raise the prospect of risk for her child.”

On a lighter note, John Oliver devoted his latest commentary to this very sort of scientific sensationalism. It should not be so, but apparently we need a comedian to tell us:

In science, you don’t just get to cherry-pick the parts that justify what you were going to do anyway. That’s religion. You’re thinking of religion.

Science is by its nature imperfect, but it is hugely important. And it deserves better than to be twisted out of proportion and turned into morning show gossip.

It’s worth remembering that a link, no matter how strong, does not equal a cause and effect relationship. So no, diet soda is probably not what’s causing childhood obesity.

Click here for a sample from the LA Times of how this story was covered. Click here for the study and here for the commentary.

Linked, photograph © Patrick McConahay / flickr

Subscribe by email to follow the accumulating evidence and observations that shape our view of health, obesity, and policy.

May 11, 2016