Research suggests that artificial sweeteners, used as a low-calorie alternative to sugar in food and drinks, may actually increase appetite and lead to weight gain.
A study conducted on animals by the University of Sydney and the Garvan Institute of Medical Research observed how sweeteners affect the brain’s ability to regulate appetite.
Fruit flies fed a diet of either yeast and sucrose (table sugar) or yeast and sucralose (an artificial sweetener) were observed for more than five days.
The flies on the artificial sweetener diet ate 30 per cent more calories than the flies eating naturally-occurring sugar, the scientists found. Once sucralose was withdrawn from their diet, calorie intake went back to normal.
The team have asserted that the mechanism responsible for this increase in appetite is due to the sweetener’s low-calorie content.
Associate Professor Greg Neely explained: “Our conclusions from this study were that the sweetness and energy content of food are integrated in reward centres in the animals’ brain.
“When they’re out of balance, the brain responds and corrects it by promoting more or less food intake, in this case more food intake. The pathway we discovered is part of a conserved starvation response that actually makes nutritious food taste better when you are starving.”
A poorer quality of sleep, insomnia and hyperactivity, which are all common symptoms of starvation, were prevalent in flies on the sweetener diet.
The study was later replicated using mice to ascertain whether the response would be the same in mammals. The findings replicated those of the first study, with the mice following the same sucralose-sweetened diet increasing their overall food consumption. The same mechanism is thought to be involved.
Despite these findings, UK dietitians aren’t going to start telling their patients to swap out artificial sweeteners in favour of sugary alternatives, as more research into whether humans experience the same reactions needs to be carried out.
Dr Ros Miller, a medical professional and member of the British Nutrition Foundation, stated: “The simplicity of the diets consumed by the rodents in these types of studies is in contrast to our highly complex diet.
“In our diets, sweetness does not reliably predict the energy contained within foods and drinks. We are more likely to use a combination of food and drink characteristics, including taste, flavour and texture, to predict energy content, rather than simply sweetness.”
A spokesperson for the International Sweetener Association added: “There is a broad body of scientific evidence from human studies which clearly demonstrates that low-calorie sweeteners are not associated with an increase in appetite, and do not have an impact on energy or food intake.”
Supporters of artificial sweeteners claim they can help reduce levels of tooth decay, obesity and type 2 diabetes, as people are consuming less sugar.