据北卡罗来纳大学教堂山校区（University of North Carolina at Chapel Hill）的研究人员调查，近三十年来美国的胖人越来越多，其主要原因是人们在日常生活中吃得太多，后者表现为不仅每一顿的份量较上个世纪6或70年代明显增多，且进餐的频率亦见增加。例如，与1977年比较美国成人每天进餐和点心的数次，至2006年平均已由3.8次增加至4.8次，其中10%的被调查者平均每天进餐和点心的次数已由5次增加至7次，由此可见一斑。进一步测算表明，2006年美国成人每天摄入的热量较上世纪70年代增加了570卡，随着摄入的热量不断增加，其结果当然是体重亦随之增加和肥胖的人儿成群。

该研究进一步支持“控制体重或减肥关键是吃得合理”这一观点，请大家注意啊！

Study finds Americans are eating more - and more often

By Ned Barnett

RALEIGH, North Carolina (Reuters) - Americans may be cutting back on super-sized meals, but waistlines continue to expand from more frequent eating, according to a study released on Wednesday.

The number of daily meals and snacks consumed by U.S. adults rose to 4.8 in 2006 from 3.8 in 1977, according to University of North Carolina at Chapel Hill researchers who examined surveys of daily eating habits over a 30-year period.

In the top 10 percent of those surveyed, the number of daily meals and snacks rose to seven from five.

The analysis also found that although the size of meal portions has stabilized in recent years, but the number of total calories consumed is rising.

By 2006, the end of the period studied, Americans were consuming 570 more calories per day than they did in the late 1970s.

A chief culprit behind the calorie gain: Americans now consume 220 more calories daily from sugar-sweetened soft drinks than they did in the 1960s, the study found.

The study is thought to be the first to examine the combined contribution of changes in portion sizes, the caloric level of foods, and eating frequency on people's total calorie consumption.

The study was funded by the National Institutes of Health, and the findings appear in the June 2011 issue of the journal PLoS Medicine.

Kiyah Duffey, a postdoctoral fellow at the UNC Interdisciplinary Obesity Center and one of the study's authors, said large portion sizes drove the rise in calories during the early part of the study period.

"Around the time people became aware of the portion sizes, we see a decline in the portion sizes they are consuming," Duffey told Reuters.

"It really seems that in the last couple of decades, it is the number of eating occasions that is driving this change."

A proliferation of food availability and a decline in regular mealtimes may be fueling the pattern, Duffey said.

"People aren't sitting down to three meals anymore," she said. "We sort of think about eating all through the day."

Some sources of dieting and health advice say frequent eating in small doses revs up the metabolism and controls hunger, and is a healthier way of eating than three big meals.

Duffey said what matters is what and how much you eat over the course of the day rather than how often you eat.

"Don't eat seven times a day if what you're eating is a salty snack or a pizza," she said. "If you're going to do that, reach for an apple instead."