Featured Research

from universities, journals, and other organizations

Eating Less May Not Extend Human Life: Caloric Restriction May Benefit Only Obese Mice

Date:
January 26, 2009
Source:
University of Southern California
Summary:
Caloric restriction only benefits obese mice, according to a new study in the Journal of Nutrition. The results suggest that caloric restriction may not be a universally beneficial anti-aging strategy, as commonly believed.

If you are a mouse on the chubby side, then eating less may help you live longer.
Credit: iStockphoto/Brandon Laufenberg

If you are a mouse on the chubby side, then eating less may help you live longer.

Related Articles


For lean mice – and possibly for lean humans, the authors of a new study predict – the anti-aging strategy known as caloric restriction may be a pointless, frustrating and even dangerous exercise.

"Today there are a lot of very healthy people who look like skeletons because they bought into this," said Raj Sohal, professor at the University of Southern California's School of Pharmacy.

He and Michael Forster, of the University of North Texas Health Science Center, compared the life span and caloric intake of two genetically engineered strains of mice.

The "fat" strain, known as C57BL/6, roughly doubles in weight over its adult life. That strain benefited from caloric restriction, Sohal said.

The "lean" strain, DBA/2, does not become obese. Caloric restriction did not extend the life of these mice, confirming previous work by Forster and Sohal.

"Our study questions the paradigm that caloric restriction is universally beneficial," Sohal said. "Contrary to what is widely believed, caloric restriction does not extend (the) life span of all strains of mice."

By measuring the animals' metabolic rate, Sohal and his colleagues came to a deceptively simple conclusion: Caloric restriction is only useful when, as in the case of the obese mice, an animal eats more than it can burn off.

"Your energy expenditure and your energy intake should be in balance," Sohal said. "It's as simple as that. And how do you know that? By gain or loss of weight.

"The whole thing is very commonsensical."

For humans of normal weight, Sohal strongly cautions against caloric restriction. In a 2003 study, he and Forster found that caloric restriction begun in older mice – both in DBA and leaner C57 individuals – actually shortened life span.

However, Sohal said that obese individuals are probably better off cutting calories than increasing their exercise to make up for overeating. Overly vigorous exercise can lead to injuries and long-term wear and tear.

In other words, it is better to skip the double cheeseburger than to turn up the treadmill after binging at Carl's Jr.

Sohal's study is not the first to question the allegedly universal benefits of caloric restriction. A study by Ross et al. published in Nature in 1976 ("Dietary practices and growth responses as predictors of longevity") found that caloric restriction works best in mice that gain weight rapidly in early adulthood, Sohal said.

Studies of caloric restriction in wild types of mouse strains have shown minimal life span extension, he added.

Next, the researchers want to understand why the obese mice have a lower metabolic rate that promotes weight gain.

The other members of the research team were Melissa Ferguson and Barbara Sohal of the USC School of Pharmacy.

Funding for the study came from the National Institute on Aging, part of the National Institutes of Health.


Story Source:

The above story is based on materials provided by University of Southern California. Note: Materials may be edited for content and length.


Journal Reference:

  1. Sohal et al. Life Span Extension in Mice by Food Restriction Depends on an Energy Imbalance. Journal of Nutrition, Jan 2009; DOI: 10.3945/jn.108.100313

Cite This Page:

University of Southern California. "Eating Less May Not Extend Human Life: Caloric Restriction May Benefit Only Obese Mice." ScienceDaily. ScienceDaily, 26 January 2009. <www.sciencedaily.com/releases/2009/01/090123101224.htm>.
University of Southern California. (2009, January 26). Eating Less May Not Extend Human Life: Caloric Restriction May Benefit Only Obese Mice. ScienceDaily. Retrieved November 28, 2014 from www.sciencedaily.com/releases/2009/01/090123101224.htm
University of Southern California. "Eating Less May Not Extend Human Life: Caloric Restriction May Benefit Only Obese Mice." ScienceDaily. www.sciencedaily.com/releases/2009/01/090123101224.htm (accessed November 28, 2014).

Share This


More From ScienceDaily



More Plants & Animals News

Friday, November 28, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Research on Bats Could Help Develop Drugs Against Ebola

Research on Bats Could Help Develop Drugs Against Ebola

AFP (Nov. 28, 2014) In Africa's only biosafety level 4 laboratory, scientists have been carrying out experiments on bats to understand how virus like Ebola are being transmitted, and how some of them resist to it. Duration: 01:18 Video provided by AFP
Powered by NewsLook.com
New Dinosaur Species Found in Museum Collection

New Dinosaur Species Found in Museum Collection

Reuters - Innovations Video Online (Nov. 27, 2014) A British palaeontologist has discovered a new species of dinosaur while studying fossils in a Canadian museum. Pentaceratops aquilonius was related to Triceratops and lived at the end of the Cretaceous Period, around 75 million years ago. Jim Drury has more. Video provided by Reuters
Powered by NewsLook.com
Tryptophan Isn't Making You Sleepy On Thanksgiving

Tryptophan Isn't Making You Sleepy On Thanksgiving

Newsy (Nov. 27, 2014) Tryptophan, a chemical found naturally in turkey meat, gets blamed for sleepiness after Thanksgiving meals. But science points to other culprits. Video provided by Newsy
Powered by NewsLook.com
Classic Hollywood Memorabilia Goes Under the Hammer

Classic Hollywood Memorabilia Goes Under the Hammer

Reuters - Entertainment Video Online (Nov. 26, 2014) The iconic piano from "Casablanca" and the Cowardly Lion suit from "The Wizard of Oz" fetch millions at auction. Sara Hemrajani reports. Video provided by Reuters
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:

Strange & Offbeat Stories


Plants & Animals

Earth & Climate

Fossils & Ruins

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