= Full article availableAnybody who regularly reads this newsletter knows that we’re big believers in breakfast. Not only is it an easy meal for consuming things people tend not to consume enough of: calcium (in milk, yogurt, or cheese), fruit (on top of cereal or mixed into yogurt), and whole grains (in the cereal itself or a slice of whole-wheat toast). But it can also provide a psychological boost to anyone trying to lose weight: start the day off with the right foods, and you’ll be less inclined to mess up your pound-shedding effort later in the day. Now, a researcher has discovered that there might be a biological basis to controlling calories by eating breakfast.
In an analysis of 7-day diet diaries kept by almost 900 men and women, John M. de Castro, PhD, a scientific investigator at the University of Texas at El Paso, found that a given number of calories eaten earlier in the day proves more satiating than the same number of calories consumed later on and blunts overall calorie consumption. Calories eaten late in the day, on the other hand, tend not to be as satiating, so that the more eating saved for evening, the more eaten in general.
For example, if you consume 300 calories at breakfast, say, half a large bagel with an ounce of cream cheese and a cup of coffee with sugar and milk, you might end up eating 2,000 calories for the day. But if you eat 400 to 500 calories at breakfast—perhaps a serving of whole-grain cereal with a sliced banana and cup of skim milk, along with a hard-boiled egg or a small container of low- or nonfat yogurt and the coffee—you might eat only 1,800 calories by the time the day is over. The numbers are going to be different for different people, “but that’s the gist of it,” Dr. de Castro comments.
Why do people apparently feel more sated by a particular amount of food eaten earlier in the day? “There is no understanding of exactly what’s happening,” Dr. de Castro comments, “but it may be that our physiology is set to certain diurnal rhythms” that are out of whack with the way humans currently live. For instance, he postulates, maybe our mechanism for feeling sated is in full swing in the morning, when we need calories to get through the activities of the day, but shuts off when the sun goes down, which didn’t used to matter because people went to bed when there was no more light. Up until 100 years ago, he points out, “the advent of night greatly restricted activity.” But now, with artificial light created by electricity, people remain active long into the evening, with a lot of opportunities to eat yet not feel sated. Indeed, Dr. de Castro found in his research that as the day wears on into evening, the time intervals between eating episodes get shorter and shorter—an average of 4 1/2 hours between breakfast and the next meal, for instance, as opposed to 2 hours between mid-afternoon eating and dinner time eating, and 90 minutes between dinner time eating and nighttime eating. In other words, eating later in the day is much more likely to be followed up soon after by more eating than eating in the morning—even if you eat a lot of calories during dinner and after-dinner snacking.
Dr. de Castro notes that it’s a “small effect” he has found with regard to time of day. There’s “lots of noise going on,” he says, with “social factors, schedules, proximity of food” while television watching and “all kinds of other things affecting your eating patterns.” Still, he says, his results do suggest that the satiety effects of eating a substantial breakfast may carry over into the Law and Order hours. Eat a hearty morning repast, and you may be less inclined to reach into the cupboard later in the day.
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