July 11, 2003

WORCESTER, Mass.— As public health leaders grapple with the epidemic of obesity in the United States, researchers at the University of Massachusetts Medical School have found the more often people eat each day, the less likely they are to be obese; and people who skip breakfast altogether are 4.5 times more likely to be obese. The study also found that people who eat breakfast and dinner frequently away from home have an increased risk to be obese.

These and other findings are reported in a study published July 1 in the American Journal of Epidemiology. “Obesity in the United States is a tremendous problem. And what we found, observing these otherwise healthy people, is that it’s much better for people to spread their caloric intake out over multiple smaller meals throughout the day,” said Yunsheng Ma, PhD, assistant professor of medicine at UMMS, the lead author of the study. “And people shouldn’t skip breakfast, that is very important.”

Dr. Ma’s study analyzed data collected from 499 people in Worcester County from 1994 to 1998, as part of a National Institutes of Heath funded blood cholesterol study conducted by Ira S. Ockene, MD, the David J. and Barbara D. Milken Professor of Preventative Cardiology at UMMS. Each subject was followed for one year, with his or her eating patterns charted at five different times during the year.  Ma’s team also tracked the physical activity of the subjects, to control for the variables of exercise and energy consumption, thereby focusing the analysis solely on the connection between eating patterns and obesity. That analysis showed that people who ate four or more meals over the course of a day were 45 % less likely to be obese compared to people who ate three or fewer meals. People who ate more often tended to eat smaller portions at each meal, the study found, and even if they consumed the same total number of calories during a 24 hour period, they still were far less likely to be obese.

The probable reason for the differential, Ma said, is that spreading out the calories keeps a more stable level of insulin in the blood. Eating fewer, larger meals spikes insulin levels in the blood that in turn causes more blood sugars to be taken up and stored in the body’s fat cells. “We saw some people who ate only one full meal a day. They’d skip breakfast, have a couple of cups of coffee or soda during the day, and then eat a large dinner. That’s a real problem,” Ma said. “That creates a large insulin spike, and you get more fat deposited as a result.”

Ma also found a correlation between eating meals away from home and obesity.  People who ate more breakfasts and dinners away from home had approximately twice the risk of being obese than those who ate more meals at home. “Both breakfasts and dinners away from home were significantly higher in total calories, percentage of calories from total fat and percentage of calories from saturated fat,” the study reads.

In the study Ma used the generally accepted definition of obesity as having a body mass index of 30 (kg/m2) or more. Recent national studies have shown the number of Americans who are obese has jumped 61% since 1991. Today some two-thirds of Americans are overweight (BMI of 25 to 30), with nearly 30 percent of the country’s adult population now considered obese. The rise in obesity is believed to be a key factor in the dramatic increase in type 2 diabetes in the United States.  “With that kind of increase in obesity rates, over a relatively short period of time, it’s hard to see that as having a genetic cause,” Ma said. “I think it’s clear that our eating habits, our level of physical activity, and this environment where we super size our meals, is driving this obesity epidemic. So I hope this study will help people change their eating patterns in ways that will improve cut their risk of obesity, and thereby improve their health.”

The University of Massachusetts Medical School ( ) is one of the fastest growing medical schools in the country, attracting more than $143 million in research funding annually.  A perennial top finisher in the annual US News & World Report ranking of primary care medical schools, UMMS comprises a medical school, graduate school of nursing, graduate school of biomedical sciences and an active research enterprise, and is a leader in health sciences education, research and public service.

Contact: Michael Cohen, 508-856-2000