The warring of the diet factions continues today in a slightly more scientific fashion. A 2003 paper published in the Journal of the American College of Nutrition claimed that individuals who consumed ready-to-eat cereal, cooked cereal, or, oddly, “quick breads”—waffles, pancakes, pastries, and the like—had lower BMIs than those who ate meat and eggs or abstained from breakfast entirely. But a 2007 study found the opposite: Obese women who ate two eggs for breakfast daily for eight weeks lost 65 percent more weight than their bagel-fed counterparts. Like most prescriptive studies, however, these two must be taken with a grain of salt (or, in the case of the cereal study, a few granules of sugar): Kellogg funded the former; the American Egg Board funded the latter. Among those in the field of nutrition research, it is widely acknowledged that, for a variety of reasons ranging from flawed study design to buried negative results, industry-funded studies tend to find industry-favorable results. For instance: The Tufts study that found that Quaker instant oatmeal (and, to a lesser degree, Cap’n Crunch) improved cognitive performance was funded by Quaker, the maker of both products.
The studies and advice grow ever more specific and contradictory: If your aim is to optimize attention span and memory—especially in children—then, according to one study, the best breakfast is ham and hard cheese on whole-grain bread. If you want to prevent heart disease (and who doesn’t?), try whole-grain cereal; one bowl per day is associated with a 28 percent lower risk of heart failure. If you’re a woman hoping to conceive a boy, then, according to a recent study from the University of Exeter, you should increase your breakfast consumption by approximately 400 calories daily. (Women with the highest caloric intake had boys 56 percent of the time, compared with 45 percent with the lowest caloric intake.) It’s enough to make one feel inclined to take refuge in Vonnegut’s breakfast of champions: a morning martini.
And yet, even as they disagree on the specifics, the majority of researchers seem to agree that what we put into our bodies in the morning is a critical decision. Because it occurs after eight, ten, or even twelve hours of sleep, the breakfasting moment is physiologically unique. “The nature of the food we eat affects hormones in profound ways for many hours after a meal, and that’s more important after breakfast,” said Dr. David Ludwig, associate professor of pediatrics at Harvard Medical School and author of Ending the Food Fight. “We’ve been fasting and stress hormones are elevated and we’re insulin-resistant, so we can use the properties of food at this time to our benefit or our detriment.” A fasting body is particularly sensitive to, say, a sugary, refined-starch, low-fiber muffin; blood sugar will soar and then plummet, leaving you famished once again.
What’s preferable, according to Ludwig, is to choose breakfast foods with a low glycemic index (GI). The term refers to the rate at which glucose is absorbed from carbohydrates—or, put another way, how rapidly carbohydrates affect blood sugar. This is important because controlling insulin and blood-glucose levels in turn controls appetite and, ultimately, weight. In a 1999 study led by Ludwig, twelve obese teenage boys were fed at various occasions high-GI (“instant oatmeal”), medium-GI (“steel-cut oats”), and low-GI (“a vegetable omelette and fruit”) breakfasts and lunches, and then were allowed to consume all the food they wanted for the rest of the day. The high-GI cohort, in a state of crashing blood sugar and surging adrenaline induced by the instant oatmeal, devoured 500 to 600 extra calories. (This phenomenon likely explains that postprandial ravenousness I often experience—my morning mainstays, toaster waffles and quick-cooking oats, rank fairly high on the GI list.) Low-glycemic foods may even help breakfasters achieve that dietary holy grail: speeding up metabolism. In another study, subjects kept on such a diet saw their metabolic rate shift slightly to burn approximately 80 more calories per day—not a lot, but every little bit helps.
How to tell if a food has a low glycemic index? A quick rule of thumb: The more processed the food, the higher its GI; the higher a food’s fiber content, the lower its GI. Breakfast, in other words, should be a high-fiber affair. This means vegetables and fruits (but not juices—the fiber is in the pulp and skin) and whole grains. For the record, a whole grain is an intact, unrefined grain that retains the bran and germ, its nutrient- and fiber-rich components.
Eggs too may help to control blood sugar (protein stimulates the release of glucagon, a hormone that counterbalances insulin), but don’t defect to the Atkins camp just yet. Eggs are also high in cholesterol. Many doctors, noting that sensitivity to dietary cholesterol varies, advise limiting eggs to several per week.
So what, then, to eat? The path of bread crumbs—or cereal flakes—through the thicket of breakfast suggestions is this: Breakfast is not dessert. Most muffins and bagels are out, as are those breakfast bars with the creepy strip of ersatz milk, and the many cereals that claim to be “whole grain” but are in fact sugary and fiberless. Out too are my beloved toaster waffles, unless I find a version containing the recommended five grams of fiber per serving. What remains are the foods that we probably should have been eating all along: unprocessed, low-GI, fiber-rich foods like fruits, vegetables (in omelettes if nowhere else), oatmeal (slow-cooking or steel-cut rather than instant), whole-grain breads and cereals (that are also high in fiber and low in sugar), protein in the form of low-fat dairy, and eggs in moderation. Nothing too exciting, but then, breakfast is all business. If you’re looking for thrills, try dinner.