Thomas Sergeant Perry Reading a Newspaper

Headlines vs Science on Obesity and Nutrition at OW2018

It’s a recurring frustration. Science is a difficult process of stepwise efforts to uncover the truth. We never get it all at once. And then – especially when the subject is obesity and nutrition – a battle of headlines vs science emerges. Yesterday, this frustration was on vivid display in a packed lecture hall at ObesityWeek.

On top of all of that, we received the latest chapter in an ongoing scientific debate about the carbohydrate-insulin model for obesity. The occasion was the George Blackburn Symposium, chaired by Caroline Apovian.

New Data in the BMJ

David Ludwig and Cara Ebbeling presented their latest work on the carbohydrate-insulin model of obesity. In a nutshell, they contend that refined carbs are causing metabolic dysfunction and obesity in many people. This happens because a diet with a high glycemic load stimulates fat storage, they say.

In line with this theory, they have a new peer-reviewed paper in the BMJ. They studied people following three different diets with different levels of carbs. Their endpoint was the energy burned by subjects on those different diets. And they found the answer they wanted:

Consistent with the carbohydrate-insulin model, lowering dietary carbohydrate increased energy expenditure during weight loss maintenance. This metabolic effect may improve the success of obesity treatment, especially among those with high insulin secretion.

Even though this study was all about metabolism, the headlines were not. Reporters made it all about losing weight and keeping it off. Voilà! Data turns into speculation.

Looking for Differences, Coming Up Dry

Chris Gardner presented a very entertaining review of his exhaustive study of low-fat versus low-carb diets. He lamented how various headlines has twisted his simple conclusion. He found very similar outcomes – regardless of diet, genotypes, and insulin metabolism. But health reporters tried to make it into a study that knocks genetic testing. Or calorie counting.

Unfortunately, simple sound bites often don’t work for a complex subject like nutrition. In a battle of headlines vs science everyone loses.

Commentary and Controversy

In case you doubted that this is a difficult subject, Kevin Hall was there to present some questions about methodology. It’s a bit technical. But his bottom line is that the methods for measuring energy use might not work right for low-carb diets. It’s not that the methods are completely inadequate. But they need further refinement, he says.

Ludwig and Hall have debated the carbohydrate insulin model before. Ludwig believes in it. Hall is skeptical. So it wasn’t terribly surprising when Ludwig took issue with Hall’s concerns about methodology. He thanked Hall for acknowledging his careful and very transparent work. But then he said:

I disagree with everything else that Kevin said. So I’ll make six brief points to explain why.

Maybe this debate will end someday. However, we’re not counting on it. Nor are we counting on health reporters to provide much clarity. They benefit more by stirring up controversy.

Click here for the study in BMJ and here for a paper (not yet peer-reviewed) explaining Hall’s questions about the methods. For a sample of reporting on the Ludwig’s paper, click here.

Thomas Sergeant Perry Reading a Newspaper, painting by Lilla Cabot Perry / WikiArt

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November 15, 2018

One Response to “Headlines vs Science on Obesity and Nutrition at OW2018”

  1. November 15, 2018 at 2:06 pm, Cathy Arsenault said:

    Thank you for always putting it all out there. That is what matters. We will learn and grow from hearing all sides.
    Having suffered with Obesity my entire life ~I am not finding it as cut and dry as I see in any of these “diets” but I am one person. So I will continue to read, listen,learn and hear what the experts are saying. Thank you for always telling us what is being published. Thank you everyone for working on Obesity.