Cravings for sweet foods could soon be stopped by essentially flicking a switch in the brain, scientists claim.
Researchers found the brain can be manipulated to remove emotional attachment to foods, meaning cake-lovers could suddenly feel no pleasure when they eat it.
If a specific connection between two parts of the brain which are linked to the tongue is switched off, the ability to taste is not lost, but the brain stops enjoying specific tastes.
When the same sweet receptors are turned on the brain reacts to plain water with the same pleasure as if it were sugar, the study on mice found.
The scientists at Columbia University in New York say the findings could help them treat eating disorders such as obesity and anorexia by altering people’s relationship with food.
Many people feel guilty about craving sweet food and the new research by the Zuckerman Institute suggests it could be possible to turn off enjoyment of sugary snacks
The study examined how sweet and bitter tastes affect the brain and how they could be controlled.
The brain naturally prefers sweet tastes to bitter ones, but that could be changed by manipulating the amygdala – part of the brain which judges signals from the senses.
Possible to stop food producing memories or emotions
The paper’s senior author Dr Charles Zuker said: ‘When our brain senses a taste it not only identifies its quality.
‘It choreographs a wonderful symphony of neuronal signals that link that experience to its context, hedonic value, memories, emotions and the other senses, to produce a coherent response.’
Memories, thoughts and emotions produced when tasting food could be controlled individually or removed altogether, the study found.
Other findings published today claim obese people do not get as much satisfaction from eating, so they overeat to compensate.
Using the team from Columbia’s findings it could one day be possible to make people feel satisfied sooner, or to reduce cravings.
One of the paper’s authors Li Wang, PhD said: ‘It would be like taking a bite of your favorite chocolate cake but not deriving any enjoyment from doing so.
WHAT IS THE GENE THAT CAUSES A SWEET TOOTH?
Scientists have known since 2013 that a version of the gene FGF21 makes people consume more carbohydrates.
This has been assumed to trigger people to pile on weight as they consumed more calories than their counterparts without the gene.
The FGF21 hormone, which is made mostly in the liver, has multiple functions.
It acts on the hypothalamus in the brain to suppress sugar and alcohol intake, stimulates glucose update by fat cells, and acts as an insulin sensitizer.
‘After a few bites, you may stop eating, whereas otherwise you would have scarfed it down.’
How the research was carried out
It was already known that sweet and bitter are divided the in the taste cortex – the part of the brain which understands tastes.
Previous research has also shown the taste cortex is directly linked to the amygdala, which produces the emotional reactions depending on what a taste is.
The new findings show scientists can even reverse the way tastes are perceived, making bitter food more enjoyable than sweet.
They studied the effects of using various methods – including using drugs or lights – to manipulate different areas of the amygdala in mice when they consumed water.
Scientists were able to change whether the animals tasted sweetness or bitterness in the water, and also to leave the taste unchanged but make the brain react as if the water was sweet or bitter.
The researchers in the university’s Zuckerman Institute think they can now completely rewire or turn off the links between taste and emotion.
Understanding links could improve eating disorder treatment
They say understanding how the amygdala controls the link between food and emotion could inform treatments for eating disorders.
Their findings were published in the journal Nature today.
Doctors Zuker and Wang are now investigating additional brain regions that serve critical roles in the taste system.
For example, the taste cortex also links directly to regions involved in motor actions, learning and memory.