Can artificial sweeteners actually make your feel hungrier?
Some researchers in Australia say they can, and they think they know why.
The researchers say artificial sweeteners have an effect on how the brain regulates appetite as well as on the taste perceptions in our mouth.
"These findings further reinforce the idea that 'sugar-free' varieties of processed food and drink may not be as inert as we anticipated,” said Professor Herbert Herzog of the Garvan Institute of Medical Research, in a press release. “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.”
The researchers were from the Garvan Institute and the Charles Perkins Centre at the University of Sydney.
Their study was published today in the journal Cell Metabolism.
The scientists first looked at fruit flies.
They laced the insects’ diet with the artificial sweetener sucralose for more than five days.
Those flies consumed 30 percent more calories than they did when they were given naturally sweetened foods.
The researchers then performed the same experiment using mice.
They discovered that the mice given an artificially sweetened diet experienced a “significant increase in food consumption.”
"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 Associate Professor Greg Neely of the University of Sydney Faculty of Science, in a press release.
Why this may happen
The researchers say they uncovered a neural map that explains the extra calorie consumption.
They say this neuronal network responds to artificial sweeteners by telling animals (and that includes humans) that they haven’t consumed enough energy.
The researchers concluded that inside the brain's reward centers, sweet sensations are integrated with energy content. When sweetness and energy are out of balance for a period of time, the brain recalibrates and sends out signals for more calories to be consumed.
To help push this response along, the brain enhances the flavor of certain foods, the researchers said.
"Using this response to artificially sweetened diets, we were able to functionally map a new neuronal network that balances food's palatability with energy content. The pathway we discovered is part of a conserved starvation response that actually makes nutritious food taste better when you are starving," said Neely.
The researchers also concluded artificial sweeteners promoted hyperactivity, insomnia, and decreased sleep quality, which can all be noted when people are fasting or in mild starvation mode.
Other potential explanations
If the conclusions in this study are proven to be true by further research, it could be significant for humans.
Billions of people worldwide eat food and drink liquids with artificial sweeteners. Many are overweight or obese and use the sweeteners to cut sugar from their diets to lose weight.
“This has huge implications if in fact more research shows that [the study’s conclusions] are a possibility,” Susan Weiner, a registered dietitian and nutritionist, told Healthline. “It’s very interesting. I would love to hear about more studies to see where this leads.”
However, Weiner said there are other possible explanations for the increased calorie consumption as well as other things to consider.
She noted that many people who begin consuming artificial sweeteners are overweight or obese, and may already be taking in a lot of calories.
She added that people are unique, so individual brains may react differently to artificial sweeteners.
Genetics also plays a role in obesity.
Weiner said she does allow her clients to use artificial sweeteners but only in small amounts.
“It doesn’t melt away the pounds,” she said.
Drinking water, Weiner said, is one of the best ways to lose weight and reduce sugar consumption.
Nonetheless, she is intrigued by this most recent study.
“It’s a good place to start,” Weiner said. “Artificial sweeteners are in just about everything.”