Changing Our Minds About Nutrition and Obesity

We see a lot of stubborn opinions about nutrition and obesity research. People dig intellectual trenches and defend their positions about sugar, salt, and fat. Suppositions turn into convictions. Data becomes a tool for proving a point. Or inconvenient data leads a professor say we have to stomp it out. It’s depressing, really, if we care about genuine scientific inquiry. But on the other hand, we also see noteworthy examples of scientists changing their minds on important ideas about nutrition and obesity.

So we choose to believe that scientific inquiry, data, and rigor can indeed carry us forward.

A Reconsideration of Added Sugars

Seemingly endless recitations about the great harms of added sugars have left an impression. Hyperbolic claims that sugar is toxic are still fueling great angst about Americans consuming too much of it. It’s an article of faith for many. Thus it was refreshing to read a report of new research that led a serious scientist to change her mind on this subject.

Back in 2013, Lisa Te Morenga and colleagues published a systematic review and meta-analysis of dietary sugars and body weight. She concluded that sugar consumption is a determinant of body weight. Based on her findings, she wrote that advice to reduce free sugars could serve to reduce obesity in the population.

Now, she has published a new randomized controlled study comparing the consumption of sugar in fruit to added sugars in soft drinks. She found no difference in the effect on body weight in this carefully controlled study. From this she concluded:

“Public health interventions to prevent obesity and related diseases should focus on the quality of the whole diet rather than only focusing on reducing sugary drinks or sugar intakes.”

What’s impressive here is not this particular finding. It is that this scientist was open to new data on a subject where dissent from orthodoxy is quite unpopular.

The Great Protein Fiasco

Based on a description of kwashiorkor in 1932, nutrition scientists concluded that protein deficiency was a huge worldwide problem of malnutrition for children. This turned out to be wrong, but for decades it shaped global nutrition policy. Cicely Williams was the person who first advanced this idea and then later said, “For the last 20 years, I’ve been spending my time trying to debunk kwashiorkor.”

Williams was a distinguished pioneer in maternal and child health. She was also the first female graduate of Oxford University. Though she is most known for her discovery and research on this condition, she was not shy about correcting mistaken ideas that came from her work.

Some have described “The Great Protein Fiasco” as nutrition science’s biggest error.

The Scientific Attitude

Scientists being open to changing their minds based on new data is essential. Dean David Allison of the Indiana University School of Public Health explains:

“When I observe that a scientist changes their view about an important topic, it impresses me. In my view, it is most important for scientists to be open to new findings and such open and unabashed changes of opinion in the light of new data bespeak of the scientific attitude as described by Lee McIntyre in his insightful writings.”

This is what distinguishes science from quackery and evangelistic pseudoscience.

Click here for more on The Scientific Attitude by McIntyre.

States of Mind, Those Who Stay; sketch and study by Umberto Boccioni / WikiArt

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August 2, 2021