Researchers are interested in breakfast because they are interested in obesity, and they suspect that skipping the former plays a role in fostering the latter. “The frequency of eating breakfast has declined over the past several decades, during which time the obesity epidemic has also unfolded,” write researchers Maureen T. Timlin and Mark A. Pereira in an excellent meta-analysis of all the scientific literature on breakfast to date, published in the June 2007 issue of Nutrition Reviews. Timlin and Pereira—the pair appear to be the Boswells of breakfast—also conducted the study about breakfast and body-mass index (BMI) published in Pediatrics in March. They tracked 2,216 Minnesota adolescents for five years, and found that subjects who skipped breakfast were consistently heavier than those who did not.
The relationship appears to hold for adults as well. A 2003 study published in the American Journal of Epidemiology concluded that subjects who habitually skipped breakfast (at least 75 percent of the time) had a four and a half times higher risk of obesity than those who habitually consumed it. (Those who missed breakfast even once during the study had an increased risk of obesity.) And of the 5,000-plus members of the National Weight Control Registry—registrants have lost an average of 66 pounds and have kept it off for more than five years—78 percent claim to be regular breakfast eaters.
But breakfast-eating and weight-management may not be connected in the way that we think: Despite what women’s magazines, and pop health magazines, and legions of mothers say, the mere act of consuming breakfast does not miraculously speed up one’s metabolism. In fact, it’s hard to pinpoint exactly why eating breakfast tends to coincide with healthier weight. It may be that eating breakfast simply creates a feeling of satiety, which prevents trips to the vending machine or the drive-through in the afternoon or evening. (Eating at regular intervals maintains insulin and blood-sugar levels, preventing the peaks and valleys that cause voracity.) The American Journal of Epidemiology study found that adults consumed more calories on the days they eschewed a morning meal.
Are we making ourselves hungrier, dumber, shorter-lived, slow metabolizers by not eating a proper breakfast?
The real problem, from a researcher’s point of view, is that breakfast consumption is a habit that tends to occur along with a constellation of other healthy behaviors—like exercising, not smoking, and maintaining a healthy diet—that may confound or influence the effect of breakfast on obesity. (Unhealthy behaviors, too, tend to stick together: Fewer than 5 percent of smokers eat breakfast daily.) In at least one study, when confounding variables were accounted for, the relationship between breakfast and body-mass index was not significant. The eating of breakfast was only an ancillary factor, one salubrious practice among several that contributed to slimness. Breakfasting and forgoing the gym will probably do little to reduce or control one’s weight. In the Pediatrics study, for example, it seemed surprising that the breakfast eaters often had a higher daily caloric intake and yet also a lower BMI than their breakfast-skipping peers, but when I asked Pereira what explained this finding—had eating a morning meal somehow increased the subjects’ metabolism?—he emphasized that the eaters were exercisers as well.
This is all to say that it is not yet clear to researchers whether the relationship between breakfast and obesity is causal (i.e., breakfast consumption directly influences weight) or merely associational. Breakfast may play a supporting role in weight management, rather than a starring one. Few prospective studies (in which breakfast-eating subjects are followed over a period of time) or clinical trials (in which breakfast eating is tested as an interventional therapy, as a drug might be) have been done. This is why the Pediatrics study, conducted prospectively over the course of five years, was a significant contribution to the field of breakfast studies: We can observe the correlation between breakfast consumption and BMI over time, which approximates cause and effect.
If mere consumption is not itself transformative, the question remains: What are we to eat? People have been fretting about what constitutes an ideal breakfast since at least the 1800s. Sylvester Graham, of cracker fame, promoted his high-fiber, additive-free wheat flour as a remedy for the dyspepsia epidemic of the time, which he felt was caused by the meat-centric, multicourse American breakfast: an extravaganza of pancakes, biscuits, eggs, bacon, fried ham, salt pork, and potatoes. (Such hearty fare had been fuel for the farmer but was fattening to the more sedentary industrialist.) As Scott Bruce and Bill Crawford write in Cerealizing America, the ascetic Graham believed that “meat eating inflamed the ‘baser properties,’ ” leading to masturbation—what he called “the vice”—and that “tea drinking led to delirium tremens.” Sixty years later, John Harvey Kellogg, who breakfasted on graham crackers and apples himself, also peddled grains, in the form of the first flake cereal, as a vegetarian cure for digestive trouble. You might say that breakfast has a long history of having the fun drained out of it.