Junk food could be addictive 'like heroin' - Health News - Health & Families - The Independent

Junk food could be addictive 'like heroin'

Rats became 'hooked' on sausage and cheesecake in same way as drug abusers

Junk food may be addictive in the same way as heroin or cocaine, according to a study showing that laboratory rats will endure painful electric shocks to satisfy their craving for high-calorie snacks made from sausages, bacon and cheesecake.

Scientists have found that a "café-style" diet of fatty, sugary food results in compulsive overeating among rats and causes neuro-chemical changes to the brain that mimic the sort of alterations in the human brain brought about by addiction to heroin and cocaine.

The findings lend support to the idea that certain types of energy-intensive foods can trigger compulsive overeating and obesity in humans, leading to a form of food addiction that is almost impossible to overcome by dieting.

The researchers found that rats offered junk food quickly became so attached to it that they would endure painful but harmless electric shocks to their feet in order to eat it. They would even prefer to starve themselves rather than eat the "salad bar option" of the typical rodent food eaten by rats that had never had junk food.

When the scientists analysed the brains of the junk-food rats they found that a key pleasure-reward system known to be involved in triggering drug addiction in humans was overstimulated, causing the animals to eat more and more food in order to enjoy the same chemical "high" felt in their brains.

"It presents the most thorough and compelling evidence that drug addiction and obesity are based on the same underlying neurobiological mechanisms," said Professor Paul Kenny at the Scripps Research Institute in Jupiter, Florida.

"The animals completely lost control over their eating behaviour, the primary hallmark of addiction. They continued to overeat even when they anticipated receiving electric shocks, highlighting just how motivated they were to consume the palatable food."

The three-year study, published in the journal Nature Neuroscience, tried to reproduce a diet for rats based on the sort of high-calorie, high-fat food known to contribute to human obesity. The scientists found that it was easy to accustom the rats to eating such delicacies as sausages and cheesecake.

"They always went for the worst types of food and, as a result, they took in twice the calories as the control rats. When we removed the junk food and tried to put them on a nutritious diet – what we call the 'salad bar option' – they simply refused to eat," Professor Kenny said.

"The change in their diet was so great that they basically starved themselves for two weeks after they were cut off from their junk food."

Rats showing an addiction-like behaviour towards junk food also had fewer dopamine D2 receptors in a part of the brain called the striatum compared to ordinary rats. These receptors are responsible for triggering a response to dopamine, a neurochemical that transmits signals between certain brain cells involved in the feeling of pleasure towards things like food, sex and drugs.

Fewer D2 receptors in the striatum of the human brain are associated with drug addiction, as well as a genetic predisposition towards obesity. In the case of the rats, they compensated for the fall in receptors by eating more junk food in order to stimulate the less-sensitive pleasure-reward pathway in the brain, Professor Kenny said.

"It was the animals that showed the 'crash' in brain reward circuitries that had the most profound shift in food preference to the palatable, unhealthy diet. These same rats were also those that kept on eating even when they anticipated being shocked," he said.

"When the animal overstimulates its brain pleasure centres with highly palatable food, the systems adapt by decreasing their activity. However, now the animal requires constant stimulation from palatable food to avoid entering a persistent state of negative reward.

Professor Kenny added: "These findings confirm what we and many others have suspected, that overconsumption of highly pleasurable food triggers addiction-like neuroadaptive responses in brain reward circuitries, driving the development of compulsive eating."

When normal rats had their dopamine D2 receptors thinned out by a virus, they immediately showed the same kind of addiction-like behaviour seen in rats given junk food. "Common mechanisms may therefore underlie obesity and drug addiction. [It is] as far as we know the strongest support for the idea that overeating palatable food can become habitual in the same manner and through the same mechanisms as consumption of drugs of abuse," Professor Kenny said.

Suggested Topics
Life and Style
tech
Arts and Entertainment
Robin Thicke's video for 'Blurred Lines' has been criticised for condoning rape
music
News
Paper trail: the wedding photograph found in the rubble after 9/11 – it took Elizabeth Keefe 13 years to find the people in it
newsWho are the people in this photo? It took Elizabeth Stringer Keefe 13 years to find out
Arts and Entertainment
Matt Damon as Jason Bourne in The Bourne Ultimatum (2007)
filmMatt Damon in talks to return
PROMOTED VIDEO
Life and Style
ebooksA superb mix of recipes serving up the freshest of local produce in a delicious range of styles
Life and Style
ebooksFrom the lifespan of a slug to the distance to the Sun: answers to 500 questions from readers
News
peopleThe report and photo dedicated to the actress’s decolletage has, unsurprisingly, provoked anger
Arts and Entertainment
Evil eye: Douglas Adams in 'mad genius' pose
booksNew biography sheds light on comic genius of Douglas Adams
Life and Style
tech... and together they're worth at least £100 million
Arts and Entertainment
While many films were released, few managed to match the success of James Bond blockbuster 'Skyfall'
filmsDaniel Craig is believed to be donning skies as 007 for the first time
Arts and Entertainment
Fringe show: 'Cilla', with Sheridan Smith in the title role and Aneurin Barnard as her future husband Bobby Willis
tvEllen E Jones on ITV's 'Cilla'
Life and Style
Bono and Apple CEO Tim Cook announced U2's surprise new album at the iPhone 6 launch
tech(but you can't escape: Bono is always on your iPhone)
Sport
Tim Wiese
sport
Life and Style
Kim Kardashian drawn backlash over her sexy swimsuit selfie, called 'disgusting' and 'nasty'
fashionCritics say magazine only pays attention to fashion trends among rich, white women
Arts and Entertainment
TVShows like Agents of S.H.I.E.L.D are little more than marketing tools
Arts and Entertainment
Hit the roof: hot-tub cinema east London
architectureFrom pools to football pitches, rooftop living is looking up
Latest stories from i100
Have you tried new the Independent Digital Edition apps?

ES Rentals

    Independent Dating
    and  

    By clicking 'Search' you
    are agreeing to our
    Terms of Use.

    iJobs Job Widget
    iJobs General

    Programme Test Manager

    £400 Per Day: Clearwater People Solutions Ltd: Our client are currently seekin...

    Secondary supply teachers needed in Peterborough

    £21000 - £35000 per annum: Randstad Education Cambridge: Secondary supply teac...

    Modern Foreign Languages Teacher

    £100 - £110 per day: Randstad Education Group: Full time German Supply Teacher...

    Project Manager with some Agile experience

    £45000 Per Annum: Clearwater People Solutions Ltd: Our client based in Chelmsf...

    Day In a Page

    Mystery of the Ground Zero wedding photo

    A shot in the dark

    Mystery of the wedding photo from Ground Zero
    His life, the universe and everything

    His life, the universe and everything

    New biography sheds light on comic genius of Douglas Adams
    Save us from small screen superheroes

    Save us from small screen superheroes

    Shows like Agents of S.H.I.E.L.D are little more than marketing tools
    Reach for the skies

    Reach for the skies

    From pools to football pitches, rooftop living is looking up
    These are the 12 best hotel spas in the UK

    12 best hotel spas in the UK

    Some hotels go all out on facilities; others stand out for the sheer quality of treatments
    These Iranian-controlled Shia militias used to specialise in killing American soldiers. Now they are fighting Isis, backed up by US airstrikes

    Widespread fear of Isis is producing strange bedfellows

    Iranian-controlled Shia militias that used to kill American soldiers are now fighting Isis, helped by US airstrikes
    Topshop goes part Athena poster, part last spring Prada

    Topshop goes part Athena poster, part last spring Prada

    Shoppers don't come to Topshop for the unique
    How to make a Lego masterpiece

    How to make a Lego masterpiece

    Toy breaks out of the nursery and heads for the gallery
    Meet the ‘Endies’ – city dwellers who are too poor to have fun

    Meet the ‘Endies’ – city dwellers who are too poor to have fun

    Urbanites are cursed with an acronym pointing to Employed but No Disposable Income or Savings
    Paisley’s decision to make peace with IRA enemies might remind the Arabs of Sadat

    Ian Paisley’s decision to make peace with his IRA enemies

    His Save Ulster from Sodomy campaign would surely have been supported by many a Sunni imam
    'She was a singer, a superstar, an addict, but to me, her mother, she is simply Amy'

    'She was a singer, a superstar, an addict, but to me, her mother, she is simply Amy'

    Exclusive extract from Janis Winehouse's poignant new memoir
    Is this the role to win Cumberbatch an Oscar?

    Is this the role to win Cumberbatch an Oscar?

    The Imitation Game, film review
    England and Roy Hodgson take a joint step towards redemption in Basel

    England and Hodgson take a joint step towards redemption

    Welbeck double puts England on the road to Euro 2016
    Relatives fight over Vivian Maier’s rare photos

    Relatives fight over Vivian Maier’s rare photos

    Pictures removed from public view as courts decide ownership
    ‘Fashion has to be fun. It’s a big business, not a cure for cancer’

    ‘Fashion has to be fun. It’s a big business, not a cure for cancer’

    Donatella Versace at New York Fashion Week