Thetruth about diet drinks... With so many worrying claims out there, we look at the facts behind them...

IT seems totally logical that swapping sugar-laden fizzy drinks for diet ones is much better for you.

After all, a 330ml can of sugary fizzy drink contains around 140 calories, while the diet version has zero. But a recent study of more than 66,000 women suggested a link between consuming drinks that use artificial sweeteners and a higher risk of type 2 diabetes.

Other research has also claimed links between diet drinks and health issues ranging from Alzheimer’s disease to an increased risk of various cancers.

The sugar tax was brought in by the Government to encourage manufacturers to cut down the sugar in our fizzy drinks, and has resulted in an 11% reduction.

So are the choices we’re being encouraged to make healthy ones?

“The study that suggested a link between diet drinks and type 2 diabetes was observational – which means the results don’t demonstrate cause and effect,” says Dr Stacey Lockyer, a nutrition scientist at the British Nutrition Foundation (nutrition.org.uk).

It doesn’t mean the drinks caused the condition. Instead, other diet and lifestyle factors could have been the triggers.

Dr Lockyer adds: “This study actually found that individuals with the highest consumption of both diet drinks and full-sugar drinks, but not fruit juice, had a higher risk of type 2 diabetes.

“An analysis of data from three large observational studies of healthcare professionals carried out in the US also found that replacement of full-sugar drinks with diet drinks was related to a modest lower risk of type 2 diabetes.”

Sales of Diet Coke have recently overtaken those of classic Coca Cola. But although that sounds like good news for the nation’s weight, hospital admissions where obesity is a factor have actually risen by a staggering 18%. One observational study of almost 24,000 US adults suggested an association between drinking diet drinks and obesity.

Of the people studied, 61% drank sugary drinks, while 15% drank diet versions. But of these, the obese people were the most likely to drink diet drinks.

At first look, it sounds like sugarfree drinks could be helping us pile on the pounds. But in controlled trials, people given diet drinks have been found to consume fewer calories over the course of a day compared to those drinking fullsugar drinks.

In longer-term studies, those drinking diet drinks tend to lose weight compared to those drinking full-sugar drinks. Another theory is that consuming sugar-free drinks triggers a sweet tooth, which in turn leads to us craving more sugary foods.

But, says Dr Lockyer, this idea flies in the face of more reliable research.

“A clinical trial called the CHOICE study (Choose Healthy Options Consciously Everyday) looked at the effects of consuming different food and drink choices for six months,” she explains.

“One trial group drank water instead of sugary drinks, another drank diet drinks instead of sugary drinks, and a control group made no changes.

“They found that the diet drinks and water groups consumed fewer sugary drinks and overall calories, and took less sugar in their coffee and tea, versus the control group.

“In fact, the diet-drink group ate fewer desserts too.

“This effect is consistent with a phenomenon known as ‘sensory specific satiety,’ which is when exposure to a food with one attribute (such as sweetness), can lead to a reduction in liking of foods or drinks with the same taste.” As well as diabetes and weight gain, diet drinks have been blamed for causing everything from cancer to dementia. But Dr Lockyer advises that the majority of reliable evidence suggests that diet drinks are a better choice over their sugar-packed equivalents.

“There’s been some negative press around low-calorie sweeteners and diet drinks,” she says. “But this story was largely derived from the results of a poorly conducted study that’s now been discredited.”

Cancer Research UK has confirmed that sweeteners don’t cause cancer, while the UK Food Standards Agency is clear that the 11 kinds of sweeteners approved for use in the EU are safe for use in everyday foods and drinks.

Dr Lockyer adds: “All additives, including sweeteners, have to undergo rigorous safety testing. If a new study comes to light that indicates an adverse effect, the European Food Safety Authority can be requested to look into it.”

In fact, some of the more rigorous studies conducted have found that there are benefits to choosing sugar-free drinks. In their policy statement on artificial sweeteners, the British Dietetic Association says diet drinks may help people manage their diabetes as, unlike sugary drinks, they don’t affect blood glucose levels.

Professor Louis Levy, head of nutrition science at Public Health England, says: “Our most up-to-date evidence review suggests sweeteners are safe and have a role to play in tackling obesity.”

Dr Lockyer concludes: “For people who are looking to control their weight, swapping from full-sugar drinks to diet drinks can prove to be a useful strategy.

“But ultimately, plain water always the best choice.”

It’s clear that 11 kinds of sweeteners approved for use in the EU are safe for use in everyday food & drink

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