Last updated: December 20, 2014



The truth about 'diet' products

iced tea

Top Ender Charlotte Guay was not surprised about the latest Diet Coke revelations - she prefers iced tea and juice. Picture: Supplied Source: News Limited

THE lives of everyone watching their weight were thrown into disarray this month when a leading food expert claimed that far from making us thinner, 'diet' products containing artificial sweeteners may actually be responsible for weight gain.

Catch up on the story here

For many of us, low-fat versions of our favourite foods - yoghurts, fizzy drinks, spreads, biscuits, crisps and cheese - make us feel we can safely indulge in a little of what we want without piling on the pounds, by swapping natural sugars (at 40 calories a gram) for sugar substitutes that have just two calories.

But although chemical sweeteners were once thought to be the holy grail for dieters and diabetics, opinion has started to turn against them.

So have we have been misled for years about the ability of sweeteners to help us reduce our waistlines?

Yes, says Professor Susan Swithers, who analysed scientific data from the past five years to produce her findings.

"Consuming artificial sweeteners not only adds to weight gain but, over time, is generally responsible for an increase in bad health outcomes," says the professor, who is based at Purdue University, Indiana, in the U.S.

"Our research followed people of different ages and weights (many weren't overweight at the start), and those who drank a lot of diet sodas and other artificially sweetened foods were found to suffer Type 2 diabetes, heart disease and stroke more often, and they tended to be more overweight."

But Gavin Partington, of the British Soft Drinks Association, argues that Professor Swithers' findings "run contrary to decades of scientific research".

So, who's right? Here's what you need to know…


UNLIKE naturally occurring sweeteners such as sucrose (sugar) and fructose (fruit sugar), artificial sweeteners are synthetically manufactured to be non-nutritive - so they contain few or no calories.

According to Choice, five artificial sweeteners are permitted for use in Australia: aspartame, saccharin, acesulfame K, cyclamate and sucralose.


SEVERAL studies show consuming low-calorie artificial sweeteners makes people more likely to pile on weight than reduce it, according to Joanna Blythman, author of What To Eat.

Our bodies are designed to process natural foods, so expect calories along with a sweet taste, she says.

So rather than helping us consume less sugar overall, by interfering with our satisfaction signals, artificial sweeteners cause us to crave even more sweet food.

A U.S. study showed that while people who drank one to two cans of full-sugar fizzy drinks a day increased their risk of becoming overweight or obese by nearly 33 per cent over seven to eight years, those who replaced them with diet alternatives had a 65 per cent risk.

"When you eat normal sugar, your tastebuds tell the brain sugar is on its way," says celebrity personal trainer James Duigan, of Bodyism.

"So when the body receives a low-calorie artificial sweetener instead of sugar and the calories don't reach the stomach, the body is confused." Some sweeteners are even thought to change hormonal activity, which can cause you to hold on to fat and lead to weight gain.

"Telling people to drink diet sodas could backfire as a public health message," Professor Swithers says.

"The message to limit sugar intake needs to be expanded to limit intake of all sweeteners, not just natural sugars."


"SACCHARIN can be between 200 and 700 times sweeter than sugar," says James Duigan.

"Consuming a lot makes fruit and other naturally sugary foods cease to seem sweet, causing you to develop an even sweeter tooth."

A sweet taste also increases your appetite. A U.S. study last year found non-calorific sweeteners encouraged animals to eat more calorie-rich, sweet-tasting food, making them gain weight.


LEADING nutritional therapist Dr Marilyn Glenville is the author of Fat Around The Middle and a specialist in women's health.

She has serious concerns about our consumption of artificial sweeteners, and particularly about aspartame, one of the most widely used chemical sweeteners, which is deemed safe by the Australian and European Food Standards Agencies.

"It is 180 times sweeter than sugar and can lead to binge eating and cravings. It's also been linked to mood swings and depression because it alters levels of the brain chemical serotonin," says Dr Glenville.

"There are also concerns that aspartame might be addictive - people who drink three to four cans of diet soft drinks every day, or regularly chew sugar-free gum, may experience withdrawal symptoms if they try to stop."

She always advises patients to avoid food or drinks containing artificial sweeteners - and to check the small print on ingredients even with non-diet foods.

Independent studies on lab animals have suggested artificial sweeteners can pose serious health problems, including neurological issues, memory impairment and decreased liver function.

"Aspartame is one of the most researched ingredients I can think of," says nutritionist Ian Marber. "And while some schools of thought believe it is carcinogenic, there is no proof of that.

"However, it taxes the liver and increases blood fat levels, which can lead to heart disease, diabetes and stroke risk, as well as weight gain."

Some research has even linked the consumption of artificially sweetened food and drinks to migraines and premature birth.


NUTRITIONIST Ian Marber says there is a widely held belief that naturally occurring sugars, like honey or agave syrup, are healthier than white sugar.

"But that isn't necessarily the case," he says. "Natural sugars are not harmless. I see people who wouldn't touch a can of Coke, cover their breakfast in organic agave syrup.

"Too much of any sweetener can make you gain weight."


JAMES Duigan believes xylitol and the plant-based sweetener stevia are the best options.

His tip for anyone trying to cut back on the sweet stuff altogether? "Cinnamon. It's a wonder ingredient," he says. "It tastes great, reduces cravings for sweet stuff, and helps regulate your blood sugar levels. I stir it into my coffee and eat it on yoghurt - you can add it to your breakfast porridge."


JAMES Duigan's advice is to steer clear of fizzy drinks completely. "If you want a healthy drink to quench your thirst, you can't do better than a long, cool glass of water," he says.