Thursday, August 28, 2014

Soda taxes won't stop obesity now, but they will in the future?

If a study neatly conforms to a popular political agenda, the study is probably garbage. This rule has served me well as a writer and voracious consumer of science news. Of course, there are exceptions to every rule, but when you see Mother Jones or the Huffington Post promoting a study that condemns GMOs as dangerous, snubbing the consensus of experts on the issue, your bullshit detector should go off.

So when you see a study, rather a review in this case, extolling the virtues of a soda tax over any other anti-obesity measure, you'd be among the wise to question the results before accepting the paper's conclusion.

A critical look at this study easily reveals that the authors are ignoring actual data and using statistics to push a political agenda.

Finding flaws in a statistical analysis is an arduous task (and it makes for boring blog posts, I might add), but there's a simple way to determine if researchers are lying to you with statistics: look at the data that went into their models. Even if their work was mathematically sound, they got the wrong answer if they started with bad information. The soda industry's lobby is also guilty of this, by the way.

The authors of the current study found that, compared to after school physical education programs and restrictions on junk food advertising, soda taxes are a slightly more effective way to reduce obesity--at least they will be 20 years from now.

                                                          photo: wikimedia commons

We could ruin the researchers' predictions any number of ways, but the simplest method is to point out contradictory studies -- "long-term, randomized, controlled trials," according to scientists writing in the New England Journal of Medicine -- which show that soda taxes don't work. We also have interesting data from the states with the highest obesity rates: they're still the fattest people in the country despite having to pay higher prices for sugary drinks. This is a hotly contested point, but it's probably accurate since the majority of added sugar Americans consume comes from food, according to the CDC. At minimum, then, the health mullahs are blaming obesity on the wrong part of the American diet.

 The obesity epidemic is a much more complicated beast, however. Here's one of many ways we know that. There are populations around the world who are very poor; they struggle every day just to feed and shelter themselves, and they can't stroll into 7-Eleven and buy a 12-pack of soda. They're also some of the fattest people around. Clearly something else is driving the obesity epidemic.

Soda in large enough quantities is terrible for your health. Nobody doubts this. But we need to think a little deeper about how we treat obesity, and that may require more than condescending to fat people and sticking our hands in their pockets. The factors that drive weight gain are varied, and many of them can't be addressed by telling people to cut back on calories from soda. Our bodies are far more complicated than that, unfortunately. If you're like many overweight people who have earnestly tried to lose weight, then you know what I'm talking about. Your metabolism is literally fighting your weight loss efforts.

Research confirms this point, though we know it individually as well. There are plenty of people who seemingly can't lose weight, or they lose it and can't maintain the loss. Sometimes, fortunately enough, they tweak their lifestyle in just the right and begin to see the results they want, because they addressed the underlying metabolic issue that was at the root of the problem. Rarely is that adjustment as simple as cutting out soda; everybody knows to do that first thing when they start a diet.

The public health establishment needs to get over their obsession with soda, and maybe open a biochemistry textbook.

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