Weight Regain, Microbes, and Yo-Yo Reporting

How does a mouse study about the role of gut microbes in weight regulation become a study of “yo-yo dieting?” The answer, unfortunately, is heavy-handed academic public relations and sloppy health reporting. The case in point is a perfectly good mouse study published yesterday in the journal Nature. The authors found evidence in mice that obesity changes the microbes in mice. Those changes persist even after the mice lose weight. And the microbes seem to contribute to the weight regain in those mice.

No humans and no human dieting played any role in this study.

Weizmann InfographicBut that didn’t stop the academic PR machine from promoting this as a story about yo-yo dieting. The Weizmann institute even prepared a cute little cartoon infographic. It showed people with obesity turning into balloons that inflated and deflated.

But we’re not amused.

With the encouragement of that PR blitz, health reporters generated a blizzard of misleading headlines about the microbiome and yo-yo dieting. The LA Times told its readers that this research explains “why yo-yo dieters often can’t keep the weight off.”

This mouse study has value. But it’s just one piece of a much bigger puzzle about the physiology of weight regulation and how it malfunctions in obesity. Complex neuroscience, psychology, and endocrinology is at work in this disease process. Even if the mouse study proves to be relevant in humans – a big if – bugs in the gut can explain only part of what causes weight regain. Playing a role is not the same as controlling the whole process.

More than just scientific exaggeration is in play here. The yo-yo metaphor is a disparaging and misleading description for a chronic disease. When cancer relapses, no one describes it as yo-yo cancer. Yo-yo hypertension and yo-yo diabetes would be absurd labels for those conditions. But yo-yo dieting is a great metaphor for suggesting that weight regain is somehow the fault of someone with obesity trying to lose weight through diet and exercise. The implication is that they’re doing it wrong.

That implication and thus the yo-yo metaphor is flawed. The bias that people with obesity ought to be able to cure themselves through diet and exercise perpetuates that flawed thinking.

Obesity is a chronic disease. Like any chronic disease, without effective chronic care, obesity relapses and progresses. It’s time to ditch the yo-yo’s and get serious about building the evidence for better obesity care.

Click here for the study and here for more from Reuters.

Yo-Yo, photograph © Robert Bradley / flickr

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


November 25, 2016