A little at a time: Eating and exercising in bits and pieces
It's hard to ignore advice from experts. For years, nutritionists (and mothers) have made three square meals the gold standard for healthy eating. Likewise, physiologists (and coaches) have advocated regular exercise for optimal fitness. But in today's busy world, it can be hard for someone to sit down for three meals or to stay moving for 30 straight minutes. Is there another way?
Possibly. New research suggests that frequent small meals can be nutritionally sound and that frequent short periods of exercise can add up to fitness and health. It may not be better, but it is different.
First, eating — or grazing, as the pattern is called. Over the years, scientists have observed that when animals are allowed to nibble, they have lower cholesterol levels than when they are encouraged to gorge, even though their total food consumption is the same. A study from Great Britain suggests that people in the real world may get similar results. More than 14,500 individuals between the ages of 45 and 75 volunteered for this study. When the scientists tallied the results, they found that the people who ate more frequently took in more calories. Surprisingly, though, they also had lower cholesterol levels. The difference was relatively slight, about 5%, but it was consistent and significant. In all, the researchers found that people who eat six or more times a day have cholesterol levels that should reduce their cardiac risk by 10%–20% compared with people who eat once or twice a day. And male (but not female) "grazers" were also leaner than "gorgers," even though they took in more calories.
A 2002 study of 330 French men found that those who eat more frequently have less body fat than those who eat less frequently. And a more recent study of 499 Massachusetts residents suggests that grazing has similar effects on both sides of the Atlantic. People who ate four or more times a day were 45% less likely to be obese than those who ate three or fewer times a day.
You may be able to divide your meals into snacks, but should you split your walk into segments? To answer the question, the Harvard Alumni Study investigated 7,307 men with an average age of 66. As in many earlier studies, the men who were most active enjoyed the lowest incidence of heart trouble, even after other risk factors were taken into account. But the frequency of exercise didn't influence protection one way or the other. The men who got their exercise in small chunks did just as well as those who exercised in a few longer workouts, as long as they ended up burning the same number of calories in the course of a week.
The same appears to be true for women. A study of young female college students in Wisconsin found that daily exercise was equally beneficial whether it occurred in a single 30-minute session, two 15-minute sessions, or three 10-minute sessions.
In addition, researchers in both the United States and England have found that bouts of exercise throughout the day helped clear the fatty substances that enter the blood after eating as well as 30 minutes of continuous exercise.
What does it all mean for you? To be healthy, you still have to eat right and exercise regularly. But the research shows that what you eat is more important than when you eat it, and what you do is more important than how you do it.
December 2006 Update