Three square meals a day: For years we’ve been told they are essential to health. But popular dieting advice suggests that eating more meals — albeit smaller ones — may be a better approach, especially for those looking to shed extra pounds. Some new diets advocate going the other way: consuming only one small meal a couple of days a week followed by days of unrestricted eating.
These diets claim to help people manage the tricky business of taking in fewer calories. What does science say about their effectiveness?
Let’s start with the idea that lots of little meals is better than three squares. While numerous studies have indicated a link between a snacking diet (four to six small meals or adding healthful snacks to the three squares) and maintaining a healthy weight, the research remains inconclusive.
A classic study published in the New England Journal of Medicine in 1989 compared “nibbling” — 17 snacks a day — to a traditional three meals that were equivalent in calories. Seven men ate each way for two weeks, and researchers found lower cholesterol and insulin levels with the nibbling diet — factors that lower risk for heart disease and metabolic diseases such as diabetes. And in large surveys of how people eat, researchers have found lower body weights in people who report eating more often than three times a day.
While this might suggest that nibbling (within reason) is good, surveys can find only associations, not cause and effect. In addition, though a recent review of clinical studies found that frequent meals make people feel less hungry, this eating pattern does not necessarily correlate with weight loss. That may seem confusing, but it’s the current thinking, according to Heather Leidy, an assistant professor of nutrition and exercise physiology at the University of Missouri in Columbia who co-authored the review.
At the Johns Hopkins Weight Management Center in Baltimore, overweight people seeking to shed pounds are generally advised to spread out small meals over the course of a day while keeping an eye on calories. The act of eating and digesting increases the resting metabolic rate — the calories your body burns to keep up physiologic functions without any physical exercise — so eating more frequently should favor weight loss, according to the center’s director, Lawrence Cheskin. Also, he says, “it keeps people satisfied — they’re less likely to do a big overeat.”
Unless — and this is a big unless — eating more frequently leads people to consume more calories. You can guess what happens then.
How about skipping breakfast? We’ve long been told to eat breakfast for health and attentiveness. For dieters, breakfast is thought to keep hunger at bay and prevent overeating the rest of the day.
A small study published last month pokes holes in this conventional wisdom. Researchers at Cornell University either fed breakfast to or withheld breakfast from 18 student volunteers. Those who skipped breakfast reported being hungrier than those who ate breakfast; they also ate more at lunch. Still, they did not eat enough to fully compensate for the missed meal. In fact, those who had skipped breakfast took in 408 fewer calories over the course of the day than those who ate breakfast.
Study author David Levitsky, a professor of nutritional sciences at Cornell, says his work adds to a growing body of evidence that overturns a long-held belief: that people will compensate for missed calories. Rather, skipping a meal is “one small weapon” people can use to fight the battle of weight, he says. “If you skip two to three meals per week, you can decrease” your caloric intake, he says.