Featured Research

from universities, journals, and other organizations

Overweight People May Not Know When They've Had Enough

Date:
January 14, 2008
Source:
DOE/Brookhaven National Laboratory
Summary:
Researchers have found new clues to why some people overeat and gain weight while others don't. Examining how the human brain responds to "satiety" messages delivered when the stomach is in various stages of fullness, the scientists have identified brain circuits that motivate the desire to overeat. Treatments that target these circuits may prove useful in controlling chronic overeating.

Gene-Jack Wang.
Credit: Image courtesy of DOE/Brookhaven National Laboratory

Researchers at the U.S. Department of Energy's Brookhaven National Laboratory have found new clues to why some people overeat and gain weight while others don't. Examining how the human brain responds to "satiety" messages delivered when the stomach is in various stages of fullness, the scientists have identified brain circuits that motivate the desire to overeat. Treatments that target these circuits may prove useful in controlling chronic overeating, according to the authors.

"By simulating feelings of fullness with an expandable balloon we saw the activation of different areas of the brain in normal weight and overweight people," said lead author Gene-Jack Wang of Brookhaven Lab's Center for Translational Neuroimaging. The overweight subjects had less activation in parts of the brain that signal satiety in normal weight subjects. The overweight subjects were also less likely than normal weight subjects to report satiety when their stomachs were moderately full. "These findings provide new evidence for why some people will continue to eat despite having eaten a moderate-size meal," said Wang.

Wang and colleagues studied the brain metabolism of 18 individuals with body mass indices (BMI) ranging from 20 (low/normal weight) to 29 (extremely overweight/borderline obese). Each study participant swallowed a balloon, which was then filled with water, emptied, and refilled again at volumes that varied between 50 and 70 percent. During this process, the researchers used functional magnetic resonance imaging (fMRI) to scan the subjects' brains. Subjects were also asked throughout the study to describe their feelings of fullness. The higher their BMI, the lower their likelihood of saying they felt "full" when the balloon was inflated 70 percent.

One notable region of the brain - the left posterior amygdala - was activated less in the high-BMI subjects, while it was activated more in their thinner counterparts. This activation was turned "on" when study subjects reported feeling full. Subjects who had the highest scores on self-reports of hunger had the least activation in the left posterior amygdala.

"This study provides the first evidence of the connection of the left amygdala and feelings of hunger during stomach fullness, demonstrating that activation of this brain region suppresses hunger," said Wang. "Our findings indicate a potential direction for treatment strategies - be they behavioral, medical or surgical -- targeting this brain region."

The scientists also looked at a range of hormones that regulate the digestive system, to see whether they played a role in responding to feelings of fullness. Ghrelin, a hormone known to stimulate the appetite and cause short-term satiety, showed the most relevance. Researchers found that individuals who had greater increases in ghrelin levels after their stomachs were moderately full also had greater activation of the left amygdala. "This indicates that ghrelin may control the reaction of the amygdala to satiety signals sent by the stomach," said Wang.

The study is published online and will appear in the February 15, 2008 issue of NeuroImage.

This study was funded by the Office of Biological and Environmental Research within the U.S. Department of Energy's Office of Science, the National Institute on Drug Abuse (NIDA), the National Institute of Diabetes and Digestive and Kidney Diseases, the Intramural Research Program of the National Institute on Alcohol Abuse and Alcoholism (NIAAA), and the General Clinical Research Center at University Hospital Stony Brook. DOE has a long-standing interest in research on brain chemistry gained through brain-imaging studies. Brain-imaging techniques such as MRI are a direct outgrowth of DOE's support of basic physics and chemistry research.


Story Source:

The above story is based on materials provided by DOE/Brookhaven National Laboratory. Note: Materials may be edited for content and length.


Cite This Page:

DOE/Brookhaven National Laboratory. "Overweight People May Not Know When They've Had Enough." ScienceDaily. ScienceDaily, 14 January 2008. <www.sciencedaily.com/releases/2008/01/080109112302.htm>.
DOE/Brookhaven National Laboratory. (2008, January 14). Overweight People May Not Know When They've Had Enough. ScienceDaily. Retrieved July 31, 2014 from www.sciencedaily.com/releases/2008/01/080109112302.htm
DOE/Brookhaven National Laboratory. "Overweight People May Not Know When They've Had Enough." ScienceDaily. www.sciencedaily.com/releases/2008/01/080109112302.htm (accessed July 31, 2014).

Share This




More Health & Medicine News

Thursday, July 31, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Health Insurers' Profits Slide

Health Insurers' Profits Slide

Reuters - Business Video Online (July 30, 2014) Obamacare-related costs were said to be behind the profit plunge at Wellpoint and Humana, but Wellpoint sees the new exchanges boosting its earnings for the full year. Fred Katayama reports. Video provided by Reuters
Powered by NewsLook.com
Concern Grows Over Worsening Ebola Crisis

Concern Grows Over Worsening Ebola Crisis

AFP (July 30, 2014) Pan-African airline ASKY has suspended all flights to and from the capitals of Liberia and Sierra Leone amid the worsening Ebola health crisis, which has so far caused 672 deaths in Guinea, Liberia and Sierra Leone. Duration: 00:43 Video provided by AFP
Powered by NewsLook.com
At Least 20 Chikungunya Cases in New Jersey

At Least 20 Chikungunya Cases in New Jersey

AP (July 30, 2014) At least 20 New Jersey residents have tested positive for chikungunya, a mosquito-borne virus that has spread through the Caribbean. (July 30) Video provided by AP
Powered by NewsLook.com
Xtreme Eating: Your Daily Caloric Intake All On One Plate

Xtreme Eating: Your Daily Caloric Intake All On One Plate

Newsy (July 30, 2014) The Center for Science in the Public Interest released its 2014 list of single meals with whopping calorie counts. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

    Environment News

    Technology News



    Save/Print:
    Share:

    Free Subscriptions


    Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

    Get Social & Mobile


    Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

    Have Feedback?


    Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
    Mobile: iPhone Android Web
    Follow: Facebook Twitter Google+
    Subscribe: RSS Feeds Email Newsletters
    Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins