Studies conducted by the University of Sydney on both, animals and humans, suggest that consuming artificial sweeteners can make you feel hungry and lead to eating larger amounts of food throughout the day.
This is the first time a study has revealed exactly why this type of response takes place. The complete findings can be found in the Cell Metabolism journal. The results shed light on the effects of artificial sweeteners on the brain and how it regulates appetites and changes perceptions of taste.
Researchers from the University of Sydney’s Charles Perkins Centre and the Garvan Institute of Medical Research have located a new system within the brain that senses and integrates the sweetness and energy that is contained within the foods we consume.
Lead researcher Associate Professor Greg Neely says after chronic exposure to a diet that contained the artificial sweetener sucralose, animals began to eat larger amounts of food per sitting. Through systematic investigation of this effect, it was discovered that inside the reward centers of the brain, sweet sensation is integrated with energy content. When sweeteners versus energy become out of balance for a period of time, the brain tries to recalibrate and this leads to an increase in the number of calories being consumed.
During the study, fruit flies were offered a diet that was laced with artificial sweetener for more than five days at a time. These flies were found to consume as much as 30 percent more calories in comparison to those who were eating foods that were naturally sweetened. Associate Professor Neely says when animals were investigated, it was found that they were eating more even when they had consumed enough calories for that particular day. They realized that chronic consumption of this artificial sweetener increases the sweet intensity of real nutritive sugar, which then increases the animal’s overall motivation to eat more food.
This information is very important as there are billions of people around the world that consume artificial sweeteners, many because the alternative to real sugar is prescribed as a tool to treat obesity. What’s so upsetting about doctors telling their overweight patients to consume this alternative is that up until recently, little was understood about how the sweeteners affected the brain in regards to regulating sugar. The latest study is the first of its kind to identify how artificial sweeteners can stimulate appetite, with researchers identifying a complex neuronal network that responds to artificially sweetened food by telling the animal that is hasn’t eaten enough energy for that particular day.
Professor Neely says that using this response to artificially sweetened diets, the team was able to functionally map a new neuronal network that works to balance food’s palatability with energy content. The pathway that was discovered is part of a conserved starvation response that actually makes nutritious food taste better when you are in a state of starvation.
Researchers found that artificial sweeteners cause hyperactivity, insomnia and decreased quality of sleep, behaviors that are consistent with a mild state of starvation with similar effects on sleep also reported in the past during human studies.
In order to find if artificial sweeteners also increased food intake within mammals, Professor Herbert Herzog’s lab from Garvan replicated the same study using mice. The mice which consumed a sucralose-sweetened diet for a week showed a significant increase in their food intake and the neuronal pathway involved was the same as in the fruit flies. Professor Herzog says these findings are further evidence that support the idea that “sugar free” options in processed foods and drinks may not be as inert as was anticipated. Artificial sweeteners can actually change how animals perceive sweetness of their food, with a discrepancy between sweetness and energy levels prompting an increase in the amount of calories they choose to consume.