Comparing the Charlie's Angels physiques of yesteryear with the corpulent masses of today, scientists have done the math.
The average American eats 570 more calories a day than in 1977, Reuters reports.
Snacking, not portion size, accounts for expanding waistlines in the past 30 years, according to a study funded by the National Institutes of Health in the United States.
Researchers found the number of meals and snacks consumed each day rose from 3.8 in 1977 to 4.8 in 2006.
Dietitians such as Leslie Beck recommend eating every three to four hours (no more snacking after dinner). But diet gurus such as Dr. Clay insist people should graze every two hours to stoke metabolism and keep hunger at bay.
The strategy can backfire without careful planning of nutritious meals and snacks, notes study co-author Kiyah Duffey, a postdoctoral fellow at the University of North Carolina Interdisciplinary Obesity Center.
People have gotten in the habit of eating all through the day, she told Reuters, adding, "don't eat seven times a day if what you're eating is a salty snack or a pizza."
Anyone who has watched anti-junk-food films such as Super Size Me might argue that portion sizes are the true culprit behind soaring obesity rates. But according to the study, that's only partly true. While portion sizes have increased by about 12 per cent, the average number of calories per one-gram serving of food has actually declined slightly in the past 30 years.
"The real reason we seem to be eating more [calories]is we're eating often," Barry Popkin, a professor of nutrition at the University of North Carolina at Chapel Hill, told CNN.
The findings may not be license to skip a midday banana and then lunch on a Triple Whopper with Cheese - which tips the scale at 1,230 calories - but it's definitely food for thought.
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