New research may explain just why that's happening - with a study showing that some artificial sweeteners actually make us put on weight because they cause us to eat more.

Worse still, there's mounting evidence to suggest that people can become addicted to the sugar substitutes.

Once hailed a wonder chemical, Aspartame is an artificial sweetener that provides taste without the calories. It’s ideal for the weight conscious and a perfectly healthy drink.

• Food additive warning
• Natural sugar alternatives
• Australia's sugar shakedown

But now new research claims Aspartame makes people fatter.

Researchers believe that replacing sugar with artificial sweeteners such as Aspartame causes weight gain because it encourages us to eat more.

Aspartame can be found in over 6000 common food products in grocery stores, and is commonly used in Diet Coke, Sprite and other leading soft drink brands.

The chemical contains three components called phenyl-alanine and asopartic acid which are aminos. The remainder is methyl ester, which when swallowed becomes methanol or methyl alcohol.

These components are what causes hunger and addiction.

Christine Thomas is a self-confessed diet drink addict who is worried that her addiction has led to other physical problems, which she says she “can’t shake.”

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Thomas says “I am being poisoned by Aspartame. I know that. But trying to stop is difficult."

Nutritionist and orth-molecular psychiatrist Geoffrey Leigh has seen a massive jump in brain disorders in his practice and blames Aspartame.

“It can interfere with the brain and cause neurological effects. It can also affect just about every organ system in the body," he said.

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However that hasn’t stopped Australians drinking diet soda drinks, the demand growing by twenty per cent in five years, which is the fastest in the world. One in three drinks sold in this country is diet or zero sugar soft drink.

Diet coke addict Thomas drinks up to eight to ten cans a day, and suffers from insomnia and other problems.

"I've got restless leg syndrome. I've got sleep apnea and I've got fibromyalgia," she said.

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Thomas’s nerves are sensitive to touch and her legs spasm when she tries to sleep, but she still keeps her glass of diet soft drink next to her bedside at night.

"When your body relaxes at night one side of the brain doesn't send messages to the legs to relax, and of course your legs start kicking. Without medication mine kick every 30 seconds,” she said.

Thomas is now convinced her soft drink addiction with added Aspartame is to blame.

Even though Australia’s watchdog Food Standards Australia, New Zealand (FSANZ) claims we are okay, but Leigh disagrees.

“FSANZ says we are living within the safe level. But soda drinks are totally discredited. All soda drinks, but especially Aspartame," he said.

Claims that are made about Aspartame being sugar free and something to help control the waistline are in question.

Dietician Suzie Burrell isn't surprised Aspartame is under the microscope again.

“What we know is artificial sweetener is up to 200 times sweeter than sugar. That it appears to prime the brain for more and more of these sweet foods," Burrell explained.

Scans of the brains of Aspartame drinkers show brain waves activating the food intake areas, making people itch for more sweet foods, to drink more, eat more and thereby put on weight.

Not surprisingly, the soft drinks companies and the Australian beverages council have rejected these findings, claiming Aspartame has been rigorously tested and is perfectly safe and healthy.

However the argument still rages.

Companies won't stop using Aspartame because their recipes and tastes are linked to the artificial sweetener, which is selling well across the country.

Burrell suggests that the best thing to do for Aspertame addiction is to eliminate sweets and artificial sweeteners, by going for a non-sweet tasting fluid, preferably water.

• Food Standards Australia New Zealand - www.foodstandards.gov.au
• Susie Burrell - www.susieburrell.com.au