Breakfast helps weight loss? Nutrition science is tricky

Cereal makers have happily encouraged the belief that eating breakfast can help keep us thin and bring other benefits, partly by paying for studies that seem to support the idea.

So, does that mean breakfast is bad for you? Not that either. What it does show is how difficult it can be to sort the hype from reliable dietary advice when studies are funded by the makers of Froot Loops, nutrition science is often inconclusive, and gray areas can be spun for marketing.

Take Special K. In the 1990s, Special K boxes featured findings that people who didn’t normally eat breakfast lost more weight after they started doing so.

“That was the little piece they put on the cereal box,” said David Schlundt, a co-author of the study of about 50 women. Not mentioned on those boxes: Regular breakfast eaters who started skipping the meal lost even more weight, compared to those who stuck with their routines.

That doesn’t mean particular breakfasts can’t help some people control their appetites, or bring other benefits like energy. Schlundt’s study was tiny. But it shows how easy it is to simplify the complexities and limitations of nutrition science and cherrypick the findings.

Our understanding of what’s healthy can evolve, which is why dietary guidelines are regularly updated to reflect the latest science. A recommendation that breakfast can help with weight control—inserted in 2010—is no longer in the guidelines. With its last update, the government says it looked at broader eating patterns.

To investigate the long-held idea that breakfast can prevent weight gain, researchers in 2013 reviewed dozens of studies examining the premise. Their conclusion: Popular opinion outweighed the scientific evidence.

A major issue they identified was that studies often misleadingly used language to indicate that breakfast influenced weight, even though the findings did not establish a cause-and-effect relationship. Like a lot of nutrition research, the studies drew links between physical traits and what people said they ate.

“It goes back to the idea that correlation doesn’t equal causation,” said Andrew Brown, one of the researchers who conducted the analysis. Brown, a nutrition scientist at the University of Alabama at Birmingham, noted that it could be that heavier people were skipping breakfast in hopes of losing weight.

When citing past studies, scientists also tended to mischaracterize inconclusive results in favor of breakfast. Brown chalked that up to “white hat” bias, since people are constantly told breakfast is “the most important meal of the day.”

Brown also noted that “breakfast” can consist of any number of possibilities, whether it’s cold pizza, yogurt or an egg sandwich.

It’s possible to question all sorts of dietary ideas. A study published last month, for instance, said the science behind recommendations to limit sugar was weak. That study drew criticism from health advocates because it was paid for by an industry group that includes Coke and Hershey—but it underscored the vulnerability of dietary recommendations.

Timothy Caulfield, an expert in health law and policy at the University of Alberta, said nutrition science often comes with uncertainties and shouldn’t be discarded just because it doesn’t provide slamdunk evidence. He said health experts give advice on the best available research, but there needs to be greater understanding about its limitations.

With breakfast and weight, Caulfield said there hasn’t been a pendulum swing in the data, just that the evidence doesn’t seem as powerful as once believed. / AP