Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

The more you have on your plate, the more you overeat

04.10.2004


A study by Cornell University researchers finds that when young adults are served larger portions from one week to the next they overeat by almost 40 percent. Eating larger portions over time could account for the growth of the American girth over the past 20 years, the researchers say.



"The more food we served to the college-student volunteers in our eating study, the more they ate," says David Levitsky, professor of nutritional sciences and of psychology at Cornell. "Since we know that restaurants are serving larger and larger food portions, we think that larger portions could be a major factor responsible for the increase in overweight and obesity that is so evident today."

Levitsky and former Cornell undergraduate student Trisha Youn ’01, now a student at New York University School of Medicine, asked 13 volunteers to eat a buffet lunch three times during a week. The volunteers were not told that their portions had been weighed. During the following week, the students ate three meals: Some were served portions of the same weight as the previous week, others were served portions weighing 125 percent or 150 percent more.


Volunteers who consumed the largest portions -- 150 percent larger than the week before -- ate an average of 39 percent more food, in weight, during the week than they did the previous week, an average of 273 more calories per person.

The researchers’ paper, "The More Food Young Adults Are Served, the More They Overeat," is published in the October issue of the Journal of Nutrition (134: 2546--2549).

Studies by other researchers have shown that while Americans, on average, are not using up as many calories through activities such as exercise today compared with 20 years ago, they are taking in, on average, about 200 more calories a day than they did in the 1970s. Researchers report that almost half of Americans’ meals are now consumed outside the home, and that restaurant portion sizes have jumped by between 20 percent and 60 percent over the past 20 years. Another study found that 35 percent of 181 food products reviewed jumped in size between the 1970s and 1999.Meanwhile, the prevalence of adult obesity in the United States jumped to almost 31 percent of the population in 1999 from 14 percent in 1971. Although researchers suspect that the prevalence of larger portions plays an important role in that trend, few papers have tested the relationship.

"This data supports the powerful role that environment plays in determining food intake and possible increases in body weight," says Levitsky. The study also showed 500 grams (about 18 ounces) above normal portions is the average amount that can be consumed before a person feels uncomfortable.

Levitsky says that while the student volunteers might have eaten less later in the day after overeating at lunch during the second week of the study, his studies have shown that the size of breakfast or between-meal snacks does not affect the amount consumed at subsequent meals. "Likewise, if you don’t eat for a day, you rate yourself more hungry, but you don’t eat more food the next day. We’ve also shown that when you are fed and eat 33 percent [above normal portions] per day for two weeks, the day after you stop overeating, you rate yourself as full, but again, you eat the same amount of food as you did prior to the overfeeding."

Levitsky also recently showed that the "freshman 15" is a real phenomenon: College freshmen gain an average of 4.2 pounds during their first 12 weeks on campus and that breakfast and lunch at all-you-can-eat dining facilities account for 20 percent of the weight gain.

"From a public health perspective, the results of this study are extremely encouraging," Levitsky concludes. "If it’s correct that the increase in portion size is a major cause of the epidemic of obesity, then it should be possible to stop and possibly reverse this trend toward increased body weight by taking control of size of portions served to the American people." David Levitsky

Susan S. Lang | EurekAlert!
Further information:
http://www.cornell.edu

More articles from Studies and Analyses:

nachricht Rutgers-led innovation could spur faster, cheaper, nano-based manufacturing
14.02.2018 | Rutgers University

nachricht New study from the University of Halle: How climate change alters plant growth
12.01.2018 | Martin-Luther-Universität Halle-Wittenberg

All articles from Studies and Analyses >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: In best circles: First integrated circuit from self-assembled polymer

For the first time, a team of researchers at the Max-Planck Institute (MPI) for Polymer Research in Mainz, Germany, has succeeded in making an integrated circuit (IC) from just a monolayer of a semiconducting polymer via a bottom-up, self-assembly approach.

In the self-assembly process, the semiconducting polymer arranges itself into an ordered monolayer in a transistor. The transistors are binary switches used...

Im Focus: Demonstration of a single molecule piezoelectric effect

Breakthrough provides a new concept of the design of molecular motors, sensors and electricity generators at nanoscale

Researchers from the Institute of Organic Chemistry and Biochemistry of the CAS (IOCB Prague), Institute of Physics of the CAS (IP CAS) and Palacký University...

Im Focus: Hybrid optics bring color imaging using ultrathin metalenses into focus

For photographers and scientists, lenses are lifesavers. They reflect and refract light, making possible the imaging systems that drive discovery through the microscope and preserve history through cameras.

But today's glass-based lenses are bulky and resist miniaturization. Next-generation technologies, such as ultrathin cameras or tiny microscopes, require...

Im Focus: Stem cell divisions in the adult brain seen for the first time

Scientists from the University of Zurich have succeeded for the first time in tracking individual stem cells and their neuronal progeny over months within the intact adult brain. This study sheds light on how new neurons are produced throughout life.

The generation of new nerve cells was once thought to taper off at the end of embryonic development. However, recent research has shown that the adult brain...

Im Focus: Interference as a new method for cooling quantum devices

Theoretical physicists propose to use negative interference to control heat flow in quantum devices. Study published in Physical Review Letters

Quantum computer parts are sensitive and need to be cooled to very low temperatures. Their tiny size makes them particularly susceptible to a temperature...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

2nd International Conference on High Temperature Shape Memory Alloys (HTSMAs)

15.02.2018 | Event News

Aachen DC Grid Summit 2018

13.02.2018 | Event News

How Global Climate Policy Can Learn from the Energy Transition

12.02.2018 | Event News

 
Latest News

'Lipid asymmetry' plays key role in activating immune cells

20.02.2018 | Life Sciences

MRI technique differentiates benign breast lesions from malignancies

20.02.2018 | Medical Engineering

Major discovery in controlling quantum states of single atoms

20.02.2018 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>