Sugar substitutes that are used to sweeten foods and drinks have fewer calories than sugar, but a recent study suggests they may boost appetite by tricking the brain into thinking it needs more energy.
While researchers still haven’t done studies with humans, their work with fruit flies and mice led to a surprising finding: After consuming foods laced with the artificial sweetener sucralose, both flies and rodents started consuming more naturally sweetened food—as much as 30 percent more.
"We found that inside the brain's reward centers, sweet sensation is integrated with energy content,” said lead researcher Greg Neely, an associate professor with the University of Sydney's Faculty of Science. “When sweetness versus energy is out of balance for a period of time, the brain recalibrates and increases total calories consumed."
Sweetness versus energy
The investigators knew consumption of artificial sweeteners was linked to metabolic disruptions and set out to discover the long-term effects of what they called “the sweet/energy imbalance.”
They learned the flies and mice compensated for an artificially sweetened diet by eating more; a response to a perceived sense of starvation.
The response “actually makes nutritious food taste better when you are starving," Neely told the BBC.
"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. “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."
More sweetener side effects
The researchers also found that artificial sweeteners promoted hyperactivity, insomnia and decreased sleep quality, all behaviors that are consistent with a state of mild starvation.
They said further research is needed to determine whether their findings apply to humans.
The findings were published in the journal Cell Metabolism. You can read about the study here, and a statement by the university here.
The growth of sweeteners
Artificial sweeteners emerged from 19th century research that resulted in the discovery of saccharin, which was judged to be 300 times sweeter than sugar but with fewer calories. It found its way into a variety of products, from canned fruit to chewing gum, marketed as a low-calorie sugar alternative. Later, saccharin was joined by additional sweeteners, including aspartame, sucralose and stevia.
Today, people use sweeteners in a variety of forms under such brand names as Equal, Splenda, Truvia and Sweet’N Low.
The American Dietetic Association discussed artificial sweeteners in a 2011 paper, “The Truth about Artificial Sweeteners or Sugar Substitutes.”
The ADA paper says that using sweeteners does not increase appetite or food intake – a conclusion contradicted by the new study from Australia. But the ADA paper also provides a great deal of information about how much sweetener is acceptable and who should avoid using sugar substitutes.
Discuss the use of artificial sweeteners with your nutritionist or health care provider. If you don’t have a provider, you can find a Providence provider here.