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15 Aug 2016

Millions of Australians regularly turn to artificial sweeteners to help them lose weight, but research has found that they might be doing more harm than good.

University of Sydney research has shown that artificial sweeteners could actually be making you feel hungry, eat more, and may cause hyperactivity, insomnia, and glucose intolerance.

Researchers examined the effects of artificial sweeteners on the brain in regulating appetite and in altering taste perceptions in both animals and humans.

Lead researcher, Associate Professor Greg Neely, was inspired to research the issue after he noticed his stomach growling with hunger after consuming a diet soft drink.

Associate Professor Neely said after chronic exposure to a diet that contained artificial sweetener sucralose (Splenda), animals began eating a lot more.

“Through systematic investigation, 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,” A/Professor Neely said.

Essentially, if the reward centre measures sweetness coming in from food but does not find an increase in the energy coming in, it will demand more energy, Associate Professor Neely said.

In his study with fruit flies, it was found that they consumed 30 per cent more calories when fed on a diet including the artificial sweetener sucralose for more than five days compared with when they were given naturally sweetened food.

“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 then this increases the animal’s overall motivation to eat more food,” A/Professor Neely said.

The researchers also found artificial sweeteners promoted hyperactivity, insomnia and other behaviours consistent with a mild starvation or fasting state.

Worldwide, obesity has more than doubled in the last 30 years. While debate rages over precisely what is driving this, it is generally thought there is a mix of genetic and environmental causes at work.

Millions of people are consuming artificial sweeteners in an effort to control their weight, and they are prescribed as a tool to treat obesity, despite little being known about their full impact on the brain and in regulating hunger.

The study was published in Cell Metabolism.

Kirsty Waterford

Published: 15 Aug 2016