Why brown fat is 'good' in the fight against obesity

A large waistline White fat is the 'bad' stuff which stores energy rather than burning off calories

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What produces 300 times more heat than any other organ in the body? What stops a baby from freezing to death if left in the cold? The answer to both questions is "brown fat".

Scientists have discovered that this type of fat is a good thing because it produces lots of heat by burning calories.

Unlike white fat, which clings to our hips and expands our ageing waistlines, brown fat keeps the weight off.

And that's why the race is on to find out more about brown adipose tissue, also known as brown fat, and how humans could use it to our advantage.

Start Quote

If we activate brown fat, we can eat more and not gain weight”

End Quote Prof Sir Stephen Bloom Imperial College London

When we're born we have lots of brown fat in our bodies, wrapped round the central organs to keep us warm, to help us adapt to life outside the womb.

As we grow, however, the brown fat content of our bodies decreases.

Researchers at the University of Nottingham have been using heat-seeking technology to find out if brown fat is still present in children and adults.

In the neck

Professor Michael Symonds and Dr Helen Budge from the University's School of Clinical Sciences say their research, published in the Journal of Pediatrics, shows that the neck region in healthy children produces heat.

"There is only about 50g of brown fat in the neck region and it switches on and off throughout the day as it's exposed to different temperatures or if you exercise or eat," says Prof Symonds.

Images showing brown fat in a child Thermal imaging shows brown fat on a child's neck (in red) when their hand is put in cold water

But this capacity is much greater in young children compared with adolescents and adults.

He says that the challenge is now to use this knowledge to find out what factors might switch on brown fat, and therefore prevent excess weight gain.

"The more we know about what switches on brown fat the better. It may have an immediate effect which can be retained as you get older.

"This may provide new insights into the role of brown fat in how we balance energy from the food we eat, with the energy our bodies use up."

But could it have a role to play in fighting obesity too?

It's well-known that the UK has a weight problem. Just over a quarter of adults were classified as obese in 2010, a report from the NHS Health and Social Care Information Centre said earlier this year.

Start Quote

We could add a thermogenic index to food labels to show whether that product would increase or decrease heat production...”

End Quote Prof Michael Symonds University of Nottingham
Sweaty bodies

If the power of brown fat can be harnessed then white fat's days could be numbered.

It's a nice theory, says Prof Sir Stephen Bloom, head of division for diabetes, endocrinology and metabolism at Imperial College London.

"If we activate brown fat, we can eat more and not gain weight. But we would waste energy unnecessarily, we would sweat a lot and forever be opening windows.

"We'd be hot and thin."

Anything that could mean calories are burned rather than being stored as fat sounds like a good idea - but there are dangers in using agents to activate body tissue.

"Agents have potential for toxicity. It's great if it works and it's safe, but everyone is nervous of the side effects of obesity therapies," Prof Bloom says.

Previous research on rodents and small mammals shows that they, like babies, rely on brown fat to keep warm.

"But this might not be so applicable in humans, particularly adults. That much brown fat is not natural in humans.

Baby thermogram image which senses heat The baby's back is very warm (coloured red) due to the presence of large amounts of brown fat protecting its organs

"It would be hard work to stimulate everything that way."

Burn rate

Prof Symonds is more positive, believing that his team's research using thermal imaging could lead to more useful information on what we eat.

"Potentially we could add a thermogenic index to food labels to show whether that product would increase or decrease heat production within brown fat.

"In other words whether it would speed up or slow down the amount of calories we burn."

So fat is not as simple as it seems. There are different types and the brown stuff is much better than the white.

But we have no control over the quantities of each kind in our bodies, nor how it is managed.

In the future, Nottingham researchers will look at how nutrition, exercise, and environmental and therapeutic interventions could have an impact on brown fat and its unique heat-generating properties.

In the meantime, Prof Bloom says it's a very promising area to work on.

"It could be a help in the fight against obesity, diabetes and heart problems."

Are we nearly there yet? "There's a long way to go. A decade at least."

The war against white fat is only just beginning.


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  • rate this

    Comment number 134.

    Robert Fiore

    mmmm brown fat.."


  • rate this

    Comment number 133.

    mmmm brown fat..

  • rate this

    Comment number 132.

    "Scientists have discovered...."

    This is fast become the phrase of the century. Simply because scientists discover something doesn't make it true, it only makes it a possibility that it's true.
    Think about the scientific discovery that smoking is linked to cancer/heart disease and how much action our govt. has taken to ban such a killer.

    Scientific discoveries do not bring about common sense.

  • rate this

    Comment number 131.

    All this has been known for at least 30 years and many articles have commented upon it. How come this was not known to the BBC Health reporter? Can I have her job please as she is obviously not learned enough.
    BTW there are only 1.4b TVs in the World. They cannot all have been tuned into the Olympics. I am getting fed up with the news management here.

  • rate this

    Comment number 130.

    There is a saying that the older you get the more you feel the cold, now I know why, its a lack of BROWN fat, that's why I see some people walking about in hot weather with jumpers and jackets or coats on. I'm 65, so I should be feeling the cold, no I don't, I don't even wear jumpers in winter, I go out in trousers and a short sleeved top under my coat because if I wear a jumper I sweat buckets.

  • rate this

    Comment number 129.

    *switching on brown fat now*
    *opening window*

    ...End: Brown fat

  • rate this

    Comment number 128.

    Heat production in the liver could damage it. That's what alcohol does.

  • rate this

    Comment number 127.

    Funny how people look at things and interpret them differently.
    If that baby's back was a house it would be a bad thing because it is losing heat through the walls ( or skin in this case) and the other end it is being insulated ( nappy) to keep the heat in.

  • rate this

    Comment number 126.

    As a professional scientist, I absolutely hate it when the BBC encourages the readers to rant their opinions about scientific issues when virtually none of them (usually including the journalist) have any background knowledge of the subject at all. It's not that i care what your opinion is either way, just your lack of an informed or intellectually supported argument. Sorry :o\

  • rate this

    Comment number 125.

    The thing is, I'm 20 and classified as Obese and I have less then 10% body fat, Work that one out.

  • rate this

    Comment number 124.

    I remember seeing a BBC Horizon program on this over 30 years ago, featuring shivering vs snugly warm little rodents. I expect there were infra-red photos of babies too. You'd thing that for such a crucial issue as obesity research would progress at a faster rate, or is it that Nottingham Uni is behind the times in terms of research quality but ahead in terms of self-publicity?

  • rate this

    Comment number 123.

    4 Minutes ago
    Meanwhile in the World,Mitt Romney is drumming up support for the War that will be the war of Wars
    That can't be right. There is nothing of interest happening anywhere in the world just now. I know this because the BBC News programme is being devoted to the Olympics as well as its scheduled coverage on 2 other channels. Peace reigns!

  • rate this

    Comment number 122.

    Anything above 25 deg c, I sweat like mad, if it's dry atmosphere then it just evaporates. In colder times my body generates heat, immense heat to the state where sitting in a room with someone who has the heating on makes me sweat, I walked around Austria in a short sleeve shirt at minus 17 C and in Chicago in a jumper at minus 28 deg C and never felt cold, much to the amazement of passers by.

  • rate this

    Comment number 121.

    Meanwhile in the World,Mitt Romney is drumming up support for the War that will be the war of Wars.Yes WW3,This man is even more deranged than the BUSHES and he is gaining ground on Obama.Are Americans really that stupid?Sadly I would have to say YES.

  • Comment number 120.

    All this user's posts have been removed.Why?

  • rate this

    Comment number 119.

    For anyone lecturing on obesity/exercise/diet issues, the article clearly states that brown fat is something we have a more plentiful supply of as babies/in childhood but naturally appear to deplete as we reach adulthood. Doesn't that make lack of brown fat more to do with a natural consequence of aging, rather than 'all connected with 'obesity epidemic' etc?

  • rate this

    Comment number 118.

    60. Athame57 asks "Why are people critical of this being a HYS topic? Flab is a very real problem that killing people like never before!"

    Perhaps because it's only a "real problem" for fat people who eat too much, and even they understand the problem and know the solution.

    So, really, obesity is not a problem but simply a lifestyle choice.

  • rate this

    Comment number 117.

    Due to medical reasons I gained four to five stones. It was a tragedy unfolding infront of my own eyes. Whatever the scientists say the fact remains that the majority of us want to lose weight. It is torture to do exercise at the gym for people like me, I suffer from blisters and backache. I know there is no magic formula, I must carry on with the battle against the bulge being brown or white fat!

  • rate this

    Comment number 116.

    It will be really thrilling if brown fat content of our body can be increased by any means,so that, friendly fat's concept will help people to live in a better way in the future.

  • rate this

    Comment number 115.

    yeah, why did they dig up this old news ? Probably cos usually no subject gives people more opportunity to moralize, lecture and indulge in narcissism than obesity and diet etc. If the beeb encouraged people to go out and protest more about the things that really matter, everyone would be a lot more active and healthy..


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