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.

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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 14.

    "It would be hard work to stimulate everything that way". No it wouldn't. Have a quick readup of Dinitrophenol, used in the 30s as a dieting pill. It's not hard work- it's just dangerous. Can we please stop looking for short cuts and just eat less and exercise more (or even take a look at the BBC article published recently, and just eat less)

  • rate this

    Comment number 13.

    Here we go again. About turn on another health topic. We will have gone full circle when they report that its good or bad to take Aspirin every day again.

  • rate this

    Comment number 12.

    Dear Beeb - I can't be the only one that's fed back regarding the paucity of meaningful relevant threads - can you not run these pointless distractions in tandem with real news threads?
    It's become very noticeable over the last few months just how managed HYS has become....stop stifling it!

  • rate this

    Comment number 11.

    7.Ex Tory Voter
    You are correct, indeed.

    Event he empty seats are getting more coverage by media than Syria, and all the other global news.
    Perhaps it is just a sign of the times that NOTHING is happening in the world.

    The many channels BBC has on FreeSat to cover these auspicious events is not the point, but that BBC News24 is ALSO taken over completely by their reportage.

    BBC unbiased news?

  • rate this

    Comment number 10.

    The decline in smoking may be contributing to the wider picture. I've given up for periods of 2 months to two years and pile it on if I don't keep my eye on the ball!

  • rate this

    Comment number 9.

    Well, I`ll go to the foot of our gate, fat is good for you after all, but only if it`s brown. A strange little article and no mistake, still, it does break up the wall to wall olympic articles.

  • rate this

    Comment number 8.

    Irrespective of White Brown or yellow fat, it appears to me lots of people are wasting away to nothing.

    Look at all the empty seats in the Olympic Events.
    Nothing left on them at at but a bit of dust.

  • rate this

    Comment number 7.

    Well, what d' ya know - there is news out there other than the flaming Olympics. Not sure this is the top story exactly though.

  • rate this

    Comment number 6.

    Some fat is essential to keep your organs insulated - the rest is the body's fuel tank. Some people are genetically better at storing any excess calories in their fuel tanks than others - a normal evolutionary adaption to the 'feast and famine' diets of humans for most of history. Luckily it's simple to guarantee weight loss - use MORE calories than you consume-thank the 2nd law of thermodynamics.

  • rate this

    Comment number 5.

    If people are genuinely considering artificially altering the way their body produces fat, perhaps they should just consider eating less and exercising more? Obesity is a problem, but in nearly all cases it has a very simple cure, this just seems like a quick fix for those that lack responsibility, abused by minor celebrities that will be emblazoned on the cover of Heat* magazine.

    *Bad pun alert.

  • rate this

    Comment number 4.

    My fat will be brown when I come back from Greece in two weeks.

  • rate this

    Comment number 3.

    I have psycho active white fat. I just have to look at a bar of chocolate and I put on weight. How come no one's doing research into that.

  • rate this

    Comment number 2.

    I must have brown fat too! I'm thin and sweat more than some obese people in hot weather, and I'm 44.

  • rate this

    Comment number 1.

    i have brown fat!!!
    i am always boiling hot and still thin even though i am in my late 30's!!


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