Still Life, Vegetables

Amazing Hype for a Vegan Diet Study

Step right up and hear all about an amazing vegan diet study. The Physicians Committee for Responsible Medicine (PCRM) churned out quite a PR masterpiece of hype recently. They randomized 244 people to either go on a diet or not. The diet was a ad libitum vegan diet and people cut 355 calories from their daily diet compared to the people told to do nothing different with their diet. Not so amazingly, cutting 355 calories from their diet led those people to lose weight. All of this is fuel for amazing vegan diet hype from PCRM. So they issued a press release with a predictable headline:

Plant-Based Diet Better at Reducing Inflammatory Dietary Compounds
Than Diet With Animal Products

The claim about inflammation comes from a secondary outcome measures in this study – advanced glycation end-products (AGEs). These are compounds associated with inflammation that tend to go down when people lose weight. The authors plucked AGEs from a dozen secondary outcome measures specified for this study and made it the whole focus of their paper.

A Trial of Calorie Restriction

At the end of the day, this study is all about calorie restriction by limiting the kinds of food a person can eat. It is not – despite the PCRM hype – a study of the superiority of a vegan diet for reducing inflammation. Inflammation was not even a primary endpoint for the study. The AGEs are associated with inflammation, but they are not a measure of inflammation themselves. Furthermore, plucking one of a dozen secondary outcome measures and trumpeting it as the primary finding is not really an example of good scientific rigor. In fact, it’s a bit of the opposite.

A Bountiful Collection of Primary and Secondary Outcome Measures

In total, the protocol for this study listed seven primary outcome measures and a dozen secondary measures. So these folks had a lot to choose from in building their PR masterpiece.

However, scientific merit in this study is hard to find and any merit it might have surely doesn’t come from proving something new about vegan diets. For the most part it offers redundant evidence that if you ask people to restrict what they eat, they lose weight. Losing weight in this way can provide metabolic benefits, but those benefits are only meaningful over the long term – if a person can enjoy and maintain that new pattern for eating.

There are many healthful patterns for eating. A plant-based diet or even a vegan diet can certainly be good examples. But hype such as PCRM is offering doesn’t do much for the health of people who swallow it.

Click here for the study, here for the press release, and here for an example of the misleading reporting it generated. For more about AGEs and weight loss, click here and here.

Still Life, Vegetables; painting by Pyotr Konchalovsky / WikiArt

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November 26, 2022