It’s nothing new that diet drinks and artificial sweeteners aren’t great for us, past research has found that they contribute to an increased appetite and can actually cause us to gain weight, despite what their name might suggest.
Now researchers from Sydney University’s Charles Perkins Centre and the Garvan Institute of Medical Research have taken the study of artificial sweeteners one step further to try and understand how our brains react to artificial sweeteners.
Using fruit flies, the study, published in the journal Cell Metabolism, found that when they were fed food with sucralose (also known as Splenda) over an extended period (five days in this example) they consumed 30 percent more calories than the control group.
That figure was non-existent in the same group when the artificially sweetened food was removed.
"After chronic exposure to a diet that contained the artificial sweetener sucralose, we saw that animals began eating a lot more," said lead researcher, Associate Professor Greg Neely, from the University of Sydney's Faculty of Science.
Studying the flies’ nerve impulses, the researchers found that the impulse to eat more centres around the brain’s reward centres. The brain associates sweet tastes with an expectation of more calories, and when it doesn’t get what it’s expecting, it puts out a call for more – also known as your daily trip to the vending machine.
"Through systematic investigation of this effect, we found that inside the brain's reward centres, sweet sensation is integrated with energy content. When sweetness versus energy is out of balance for a period of time, the brain recalibrates and increases total calories consumed," continued Associate Professor Neely.
"When we investigated why animals were eating more even though they had enough calories, we found that chronic consumption of this artificial sweetener actually increases the sweet intensity of real nutritive sugar, and this then increases the animal's overall motivation to eat more food."
The study was then replicated in mice, with similar results.
“These findings further reinforce the idea that 'sugar-free' varieties of processed food and drink may not be as inert as we anticipated,” says Professor Herbert Herzog's from the Garvan Institute.
“Artificial sweeteners can actually change how animals perceive the sweetness of their food, with a discrepancy between sweetness and energy levels prompting an increase in caloric consumption."
While human testing is still a way off, it's definitely food for thought.