Making metabolism more inefficient can reduce obesity

Oct 03, 2008

In a discovery that counters prevailing thought, a study in mice has found that inactivating a pair of key genes involved in "fat-burning" can actually increase energy expenditure and help lower diet-induced obesity. These unusual findings, appearing this week in the JBC, might lead to some new roads in weight-loss therapy.

Humans and other warm-blooded animals need to continually "burn fat" in order to maintain body temperature, and it's currently believed that an individual's fat-burning capacity, or thermogenic potential, is connected with obesity risk; that is, people with more thermogenic potential are less likely to become obese. In fact, bodybuilders and dieters looking to burn fat commonly use thermogenic supplements like ephedra.

In theory, lowering thermogenesis should increase the chances of obesity, but Leslie Kozak and colleagues at Pennington Biomedical Research Center found that this may not be the case. They knocked-out two thermogenic genes in mice, Ucp1 (mitochondrial uncoupling protein) and Gdm (glycerol 3-phosphate dehydrogenase) and then fed the mice a high-fat diet while rearing them at a cool 20 °C (68 °F).

Surprisingly, these mice were actually quite resistant to obesity, which resulted from the mice turning on backup heat generators, so to speak. Lacking Ucp1 and Gdm, genes that have been designed for the efficient production of heat, mouse white fat cells activated alternate, and more inefficient, fat burning pathways. In this case, though, inefficiency is beneficial, as the mice had to burn more fat than normal to stay warm (by analogy you burn more wood by warming your house with an open fire then with a well designed wood stove).

Importantly, after spending 10 weeks at 20 °C the mice retained these alternate pathways even after transferring to 28 °C (82 °F), suggesting their bodies had adapted to the change. Thus, Kozak and colleagues note, fat burning does not necessarily require making thermogenesis easier; by making it harder and forcing the body to use inefficient methods to stay warm, the same goals can be reached.

Source: American Society for Biochemistry and Molecular Biology

Explore further: Unprecedented germ diversity found in remote Amazonian tribe

Related Stories

US govt sued over sea turtles snared in shrimp nets

7 hours ago

Tens of thousands of endangered sea turtles die every year in the United States when they are inadvertently snared in shrimp nets, an environmental group alleges, filing a lawsuit Wednesday against the government.

EU alleges Google's abuses hurt consumers, innovation

7 hours ago

The European Union's escalating legal attack on Google is likely to ignite a debate about whether the Internet search leader makes life more convenient for consumers or abuses its power to squeeze out rivals ...

Space open for business, says Electron launch system CEO

8 hours ago

Space, like business, is all about time and money, said Peter Beck, CEO of Rocket Lab, a US company with a New Zealand subsidiary. The problem, he added, is that, in cost and time, space has remained an incredibly ...

EU action on Google marks divergence with Washington

8 hours ago

The EU antitrust complaint filed Wednesday against Google represents a sharp divergence with Washington, which dropped a similar investigation two years ago, citing a lack of evidence against the Internet ...

Recommended for you

Bacteria play only a minor role stomach ulcers in cattle

Apr 17, 2015

Scientists at the University of Veterinary Medicine Vienna investigated whether stomach ulcers in cattle are related to the presence of certain bacteria. For their study, they analysed bacteria present in ...

New research reveals how our skeleton is a lot like our brain

Apr 17, 2015

Researchers from Monash University and St Vincent's Institute of Medical Research in Melbourne have used mathematical modelling combined with advanced imaging technology to calculate, for the first time, the number and connectivity ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.