June 30, 2011
Americans Are Snacking Themselves To Obesity
New research suggests that snacking and super-sizing are two of the worst enemies for dieters, as Americans consume an average of 570 calories more per day than they did in the 1970s, reaching a whopping 2.374 kilocalories.
The influence of bigger portion sizes and excessive snacking outweighs the shift towards high-calorie foods. While super-size portions are part of the problem, steady snacking is a bigger culprit, experts say.
The study, published in the journal PLoS Medicine, was carried out in the United States, where researchers found that nearly a third of all adults -- more than 72 million people -- are now categorized as obese.
"We're a generation of constant eaters," Barry Popkin, distinguished professor of nutrition at the University of North Carolina at Chapel Hill, told ABC's Good Morning America (GMA). For the study, Popkin used surveys to investigate the diet of American adults since 1977. Americans increased their eating habits in the "Ë80s and "Ë90s, but more recently, have begun eating and drinking more often.
"It used to be you'd have three meals a day. And if you snacked, it was unsweetened tea or coffee," said Popkin. "Nowadays, everywhere you turn there's food. If you're driving, you have a big bag of Doritos next to you while you drive."
The proportion of obesity in the United States has grown steadily over the past 30 years as Americans tend to "eat more and do less," Dr. David Katz, director of the Yale University Prevention Research Center, told GMA.
The research team at UNC analyzed data from food surveys carried out in the "Ë70s, "Ë80s, "Ë90s and the 2000s. The surveys recorded all food and drink a person consumes in a 24-hour period. They found the daily average energy intake increased from 1,803 kilocalories in 1977 to 2,374 kilocalories in 2006. In the last decade of the study, the average daily calorie intake increased by 229 kilocalories.
Several factors are involved in energy intake -- number of calories in a specific amount of food, portion size and how many meals and snacks are eaten in a day.
The study results showed that in the top 10 percent of those surveyed, the number of daily meals and snacks rose from five to seven. The study also found that although the size of meal portions have stabilized in recent years, the total number of calories consumed is rising.
Furthermore, Americans now consume 220 more calories per day from sugary soft drinks than they did in the 1960s, the study found.
"The real reason we seem to be eating more (calories) is we're eating often," Popkin told Health.com. "The frequency of eating is probably, for the average overweight adult, becoming a huge issue."
Advertising is one of the biggest reasons why today's American adults are overweight, Popkin noted.
"It's all about making people think they want to have something in their hands all the time," he told Health.com. "Why are we snacking all the time and munching all the time? (Food) is there, it's available all the time, it's tasty. It's not very healthy, but it's tasty. It's sweet, it's salty, it's fatty -- it's all the things we love."
Lisa Young, Ph.D., an adjunct professor of nutrition at New York University, agrees that the ever-presence of snack foods has helped to drive the overeating and obesity epidemic.
"You never used to see food staring you in the face when you went to...a drugstore," Young, who was not involved in the study, told Health.com. "It's in your face and it's cheap. You go get a magazine, you can get a candy bar."
Kiyah Duffey, a postdoctoral fellow at the UNC Interdisciplinary Obesity Center and one of the co-author of the study, told Reuters that large portion sizes were the main driver of caloric intake in the early part of the study period.
But as time progressed, people moved away from portion sizes and more toward snacking. "It really seems that in the last couple of decades, it is the number of eating occasions that is driving this change," Duffey told Reuters.
An explosion of the availability of food and a decline in regular mealtimes may fuel the pattern, Duffey said. "People aren't sitting down to three meals anymore. We sort of think about eating all through the day," she added.
Some diet sources and health advice experts say frequent eating in small amounts revs up the metabolism and controls hunger, and is healthier than eating three big meals a day. But Duffey said what really matters is what you eat and how much of it is eaten throughout the day rather than how often you eat.
"We joke about the 'see food' diet. We see food and we eat it," Katz told GMA. "People panic at the thought of spending a couple of hours somewhere where there might not be refreshments on hand."
And Americans are "no longer eating at a table with a knife and fork," Keith Ayoob, director of the Rose R. Kennedy Center Nutrition Clinic at Albert Einstein College in New York City, told GMA. "As a society, we think it takes too long to eat a bowl of cereal. We want a breakfast you can hold in one hand."
As a result, Americans choose foods that are quick, easy and tasty, but are also high in calories, only to feel hungry again in a few hours or less.
But it's not just salty food that is contributing to the obesity epidemic. Sugary-sweetened drinks also pack on those pounds.
"We're drinking ourselves to death," Popkin told GMA. "Several hundred of these extra calories are coming just from drinks."
Popkin said he hopes the study, which was funded by the National Institutes of Health, will be an eye-opener for people who might not realize how many calories they are consuming on a daily basis.
"We have to focus a lot more attention on cutting down how often we eat if we're truly going to do something about this as a society," he said.
"We don't need to have food every couple hours, so we need to change the environment so that we don't encounter food everywhere we go," Katz added. "We kind of just have to grow up. We weigh too much and our health is on the line."
The study findings suggest "a new focus for efforts to reduce energy imbalances in US adults," wrote Duffey and Popkin.
Christopher Gardner, Ph.D., the director of nutrition studies at Stanford University's Prevention Research Center, in Palo Alto, California, said that although the new findings ring true, the survey-based approach has some intrinsic limitations.
Despite being nationally representative, the surveys didn't follow the same individuals over time, and in some cases also used different questions and methods, Gardner noted. Also, they relied on the participants' memory of what they had eaten in the previous 24 hours, which is often unreliable.
"When people try to describe the portion sizes they are consuming, they are often inaccurate," Gardner told Health.com, adding that similar inaccuracies may crop up when recalling and calculating the energy density of specific foods.
In our food-filled environment, said Young, "We need to be conscious of when we eat, how much we eat, and what we eat."
Young recommends sticking with three meals a day and choosing healthy snacks (such as fruits and vegetables) rather than processed foods. "And keep your portions in check," she said.
On the Net:
- PLoS Medicine Study
- University of North Carolina at Chapel Hill
- Yale University Prevention Research Center
- New York University
- Stanford University