Bitter sweet

Consuming artificial sweeteners can increase our appetites by as much as 30%, according to new research, which has identified a system in the brain that senses and integrates the sweetness and energy content of food.

A study on fruit flies by the University of Sydney’s Charles Perkins Centre and the Garvan Institute of Medical Research found that those who were exposed to a diet laced with artificial sweetener for more than five days consumed 30% more calories when they were then given naturally sweetened food.

“After chronic exposure to a diet that contained the artificial sweetener sucralose, we saw that animals began eating a lot more,” said lead researcher associate Professor Greg Neely from the University of Sydney’s Faculty of Science.

“Through systematic investigation of this effect, we found that inside the brain’s reward centres, sweet sensation is integrated with energy content. When sweetness versus energy is out of balance for a period of time, the brain recalibrates and increases total calories consumed.”

The chronic consumption of artificial sweetener increases the sweet intensity of real nutritive sugar which then increases the animal’s motivation to eat more food, he added.

Using this response to artificially sweetened diets, the researchers mapped a new neuronal network that balances food’s palatability with energy content. The pathway is part of a conserved starvation response that actually makes nutritious food taste better when you are starving, Neely explained.

The researchers also found artificial sweeteners promoted hyperactivity, insomnia and decreased sleep quality – behaviours consistent with a mild starvation or fasting state – with similar effects on sleep also previously reported in human studies.

Replicating the study using mice, Professor Herbert Herzog’s lab from Garvan found a significant increase in food consumption and the neuronal pathway involved was the same as in the fruit flies.

“These findings further reinforce the idea that ‘sugar-free’ varieties of processed food and drink may not be as inert as we anticipated,” Herzog said. “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.”

Perhaps we’re better off staying away from sugar altogether?

Until next time…