I eat breakfast every morning -- usually a bowl of Grape-Nuts with fruit, pecans and a splash of goat's-milk yogurt. See how virtuous I am? My dietary habits have been endorsed by the nation's leading gurus of good health: The Mayo Clinic says morning meals reduce hunger and stave off obesity; so do Dr. Oz and WebMD, and the editorial page of the New York Times.
Cheerleading for Cheerios has even made its way into the United States' highest kitchen -- in the Obama household, skipping breakfast is not allowed.
The pro-breakfast lobby has only got stronger in the past few months. In June, researchers at the University of Minnesota published an analysis of 18 years of survey data from 3,600 young adults and showed people who had breakfast every day gained four pounds fewer, on average, than habitual breakfast-skippers. The eaters were also at lower risk for obesity, hypertension and diabetes.
The same effect has been studied in Asia and in Europe, in children and in grown-ups, and the answer always seems to be the same: The more regularly you eat breakfast, the slimmer you'll be.
The mere fact of this association doesn't tell us very much about what breakfast really does, of course, and it's possible that the case for eggs and toast has been overblown. A study published last week in the American Journal of Clinical Nutrition starts with this simple fact -- that in spite of all these association studies, no one knows exactly what skipping breakfast might be doing to our bodies. The study goes on to make a disturbing claim: Scholars in this field of inquiry -- breakfast science -- have been fudging facts and misinterpreting the science. The literature shows signs of research bias.
That doesn't mean any of these studies is fraudulent or dubious. There certainly is a link between skipping meals and getting fat, but Andrew Brown, a nutritionist at the University of Alabama at Birmingham and lead author of the new critique, points out large surveys of people's diets and their health are, at most, suggestive. Lining up several dozen of them in a row doesn't add much more value to their claims. It could be that my yuppie morning ritual really keeps my BMI in check, perhaps by changing my metabolism or helping to control my appetite. But it's also possible my breakfast habits do nothing for me on their own, and they only correspond to some deeper determinants of health.
As a breakfast-eater, for example, I'm more likely to work out than other people. At least that was the finding of a breakfast study from 2008, which also found breakfasters tend to be rich and white, and less likely to indulge in cigarettes and alcohol. Any of these factors might protect someone from obesity and diabetes, so it's hard to know what role might be left to eating breakfast. There are other confounds, too: People with lousy sleeping schedules may have less time for making pancakes. So what makes them fat -- missing breakfast or not getting a good night's rest?
Such questions will never get a thorough answer if we're stuck with the sorts of studies that have been done so far, in which large groups of people are surveyed about their eating habits, then weighed and measured over time. For many years, scientists have known the association between breakfast and body weight. Yet they've continued to replicate the finding instead of doing followup work -- in the form of randomized, controlled trials -- that might extend our knowledge further.
Mark Pereira, a University of Minnesota researcher who published the most recent association study on breakfast and obesity in June, would like to follow up his work with a randomized experiment in which subjects are assigned to breakfast and no-breakfast groups, then followed for two months. That would give a better sense of whether breakfast really prevents weight gain, but Pereira would need a $2-million or $3-million grant to make it happen and several years of research time.
Meanwhile, the National Institutes of Health may be unwilling to invest that much money when the value of a healthy breakfast has already been established as a principle of common sense.
Why should anyone try to thumb the scale for eating breakfast? Are these scientists taking money from Big Granola? For other tricky issues in nutrition -- such as whether drinking diet soda makes you fat, or whether breastfeeding keeps your children thin -- it's hard to keep the science free of interest groups and ideology. When it comes to eating breakfast, though, there shouldn't be much controversy.
Still, it might not be such a good idea to wait around for better evidence. Eating breakfast may not really help to keep you thin, but there isn't any evidence that it makes you fat. It's also possible breakfast improves cognitive abilities and mood in kids and teenagers. So what's the harm in trying, just in case it works?