April 2001

From University of North Carolina at Chapel Hill

Like USA children, young adults snacking more now than they did two decades ago

CHAPEL HILL - Today, young adults in the United States eat more snacks than they did in the 1970s, a new University of North Carolina at Chapel Hill study concludes. A large increase in total energy from snacks, coupled with increased energy contained in those foods, undoubtedly contributes to the nation's obesity epidemic, researchers say.

The study, which involved responses to detailed surveys of 8,493 U.S. residents, appears in the April issue of the journal Preventive Medicine. Authors of the paper, all at the UNC schools of public health and medicine, are dietitian Claire Zizza, a doctoral student in nutrition; Dr. Anna Maria Siega-Riz, assistant professor of nutrition and of maternal and child health; and Dr. Barry M. Popkin, professor of nutrition.

The two professors, also fellows at the UNC Carolina Population Center, released a different study in the Journal of Pediatrics April 6 showing U.S. adolescents also are eating between meals more often than in the past.

Information analyzed for the investigation came from the U.S. Department of Agriculture's 1977-78 Nationwide Food Consumption Survey and both the 1989-91 and 1994-96 Continuing Survey of Food Intake by Individuals. "In this study, we looked at 19- to 29-year-olds because people in that age group are going through transition -- leaving their parents' homes and becoming much more independent in choosing what and how they eat," Zizza said. "Studies of children and adolescents suggest a large increase in the role of snacking, but little was known before now about this behavior in young adults."

Researchers found that snacking prevalence -- the percentage of people who ate snacks during the survey -- increased in the young adult age group from 77 percent to 84 percent between 1977-78 and 1994. The nutritional contribution of that food to total daily energy intake climbed from 20 percent to 23 percent, chiefly because energy consumed per snacking occasion increased by 26 percent, and the number of snacks per day rose 14 percent overall.

"Snacks going from a fifth of people's total daily caloric intake to almost a quarter might not sound like a lot, but when you look at how many calories that is and how they accumulate over weeks and months, it really is quite a bit," Zizza said. "You only need 3,500 extra calories to gain a pound."

The energy contribution of high-fat desserts to total calories from snacking decreased from 22 percent to 14 percent, but those foods remained the largest single source of energy, she said. The energy contribution of salty, high-fat foods doubled, and both sweetened drinks and alcohol -- mainly beer -- remained important contributors of empty calories.

"It's clear that the nation is in the midst of an obesity epidemic, but why is not so evident," said Zizza, who worked for the U.S. Department of Agriculture as a dietician for seven years before returning to school. "Some people say Americans eat too much, while others say lack of exercise is the problem. Even genetics might play an important role."

Obesity is increasing in all age groups, she said. Being overweight chiefly results from an imbalance between the amount of energy taken in as food and the amount of energy expended in daily life activities. "Snacking in and of itself is not bad, but the choice of foods we make often are," Zizza said. "We can choose healthy snack foods, and if we do, they can become a really important part of a well-balanced diet."

Note: Zizza can be reached at 919-966-1734 (w) or 919-932-2825 (h). Siega-Riz's work numbers are 919-962-8410 and 919-966-5984.

School of Public Health











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