NEWS

Study: weekends chief culprit for overeating by Americans

By DAVID WILLIAMSON
UNC News Services

CHAPEL HILL – As a group, young and old, Americans overeat, and a new University of North Carolina at Chapel Hill national study shows much of that overindulgence occurs on weekends.

UNC School of Public Health and Carolina Population Center researchers found that the average American, age 2 and above, consumes 82 kilocalories more on Fridays, Saturdays and Sundays than he or she does Monday through Thursday.

That difference is important, scientists say, and needs to be considered in clinical treatment and research trying to figure out how to combat the current U.S. obesity epidemic. An average 10-kilocalorie positive energy imbalance per day increases a person’s weight by a pound a year.

"There are two key results from this study," said Dr. Barry M. Popkin, professor of nutrition at the School of Public Health. "First, consumption on Friday, Saturday and Sunday are all similar so the ‘weekend’ encompasses all three of these days. Second, the overall increases in dietary intake are significant for the overall sample and are largest for the 19- to 50-year-old age group.

"In that age group, the weekend increase is 115 kilocalories per day. The increased proportions of energy from fat and alcohol consumed on weekends are greater for that age group and account for most of the increase in energy intake," Popkin said. "Out of the 115 kilocalorie per day on weekends, 42 come from alcohol and 50 from fat."

A report on the study appears in the August issue of Obesity Research, a professional journal. Besides Popkin, authors are Drs. Pamela S. Haines, associate professor of nutrition; Dr. Mary K. Hama of the U.S. Department of Agriculture’s Agricultural Research Service and Dr. David K. Guilkey, professor of economics at the UNC College of Arts and Sciences’ economics department.

The study involved analyzing data from the nationally representative, federally funded 1994 to 1996 Continuing Survey of Food Intakes by Individuals. Researchers looked specifically for differences between energy, fat and alcohol intake by days of the week. Their analysis of various age groups combined included caloric intake during roughly 28,000 days.

"Because the 19-to 50-year-old group consumes 115 kilocalories more each weekend day than weekdays in a given year, the weekend impact to this group would total 17,940 additional kilocalories or almost five pounds," Popkin said. "The dietary intake differences are particularly important for that group and for people between 51 and 70 because younger and older people have less of an imbalance on average, and their weight gain would be about three quarters of a pound a year."

In the sample they analyzed, fall seemed to be the peak season for energy intake, he said, possibly because people’s eating tends to increase as colder weather returns.

Among younger adults -- those under age 50, the greatest weekend increase in kilocalories came from alcohol. Among adults between ages 51 and 70, the largest increase came from higher fat consumption.

A grant from the USDA’s Beltsville Human Nutrition Research Center’s Food Survey Research Group funded the research.

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Note:  Popkin can be reached at (919) 966-1732, Haines at (919) 966-7233.

UNC School of Public Health Contact: Lisa Katz, (919) 966-7467
UNC News Services Contact: David Williamson, (919) 962-8596