Australian researchers found that a continual diet of the artificial sweetener sucralose set off a series of mechanisms that caused an increase in food intake.
Although the experiments were conducted on fruit flies, the team believe that similar observations could be noted in humans.
As more people switch to artificial means to gain the sugar ‘rush’ without the drawbacks, these findings may well cause concern amongst individuals looking to shed weight and make health gains.
The study
To investigate if consumption of a sucralose-sweetened diet impacted on flies' energy usage, researchers fed them a standard control diet of sucrose and yeast or a diet of sucrose and yeast with sucralose added.
These flies were then removed from the sucralose diet. Sucrose and yeast intake was then determined over the next 24 hrs.
Results revealed that exposure to the sucralose-infused diet for prolonged (more than 5 days) periods exhibited an increase in food intake and calories consumed. This effect was observed in both male and female animals.
"Through systematic investigation of this effect, we found that inside the brain's reward centres, sweet sensation is integrated with energy content,” said lead researcher and associate professor Greg Neely from the University of Sydney.
“When sweetness versus energy is out of balance for a period of time, the brain recalibrates and increases total calories consumed."
Mechanism not defined
Despite its popularity, the effect of artificial sweeteners on health remains unclear. Experiments using animal models define a role for these sweeteners in metabolic disruption. Its exact mechanisms of action also remain unclear.
Rats given a saccharin solution showed increased food intake compared to animals given water. This increase occurred even when the sweetener was removed from the diet.
Additional studies have also shown animals consuming synthetic sweeteners exhibit weight gain, accumulation of body fat or impaired glucose homeostasis.
"These findings further reinforce the idea that 'sugar-free' varieties of processed food and drink may not be as inert as we anticipated,” said co-author Professor Herbert Herzog of the Garvan Institute of Medical Research.
“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."
Commenting on the study, Dr Dominic Dwyer, Reader in Psychology at Cardiff University, said that further work would be needed to confirm the systems revealed in the current work are also at play in humans.
"The effects of exposure to artificial sweeteners persists for a long time. It seems only to impact on the behaviour of the flies for about 3 days. So, there might be some differences in the way that sweetener exposure affects food consumption in flies and mammals."
Source: Cell Metabolism
Published online ahead of print, doi:10.1016/j.cmet.2016.06.010
“Sucralose Promotes Food Intake Through NPY and A Neuronal Fasting Response.”
Authors: G. Gregory Neely et al.