Do artificial sweeteners actually make us want to eat more?
Artificial sweeteners are a go-to for dieters because they combine sweetness with few calories.
However, some studies have shown that sugar alternatives can actually increase the amount people eat, especially foods which are high in calories.
Research conducted by Australian scientists has tried to uncover how this happens. Experts from the University of Sydney's Charles Perkins Centre and the Garvan Institute of Medical Research claim they have found a new system in the brain which senses and integrates the sweetness and energy content of food.
Professor Greg Neely, who led the research, said: "After chronic exposure to a diet that contained the artificial sweetener sucralose, we saw that animals began eating a lot more.
"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."
In the study, fruit flies that were exposed to a diet laced with artificial sweetener for prolonged periods - more than five days - were found to consume 30 per cent more calories when they were then given naturally sweetened food. The research was only done on fruit flies, but experts say this is a tried and tested method for studies of this kind. Some further research has been done on mice, which takes it a stage closer to humans.
"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," said Professor Neely. Or, in other words, use of artificial sweeteners may make consumers want to consume more calories, rather than less.
The researchers also found artificial sweeteners promoted hyperactivity, insomnia and decreased sleep quality – behaviours consistent with a mild starvation or fasting state – with similar effects on sleep also previously reported in human studies.