Sorry, George... Diet Coke’s just as bad for our waistlines as the real thing

HEALTH campaigners were celebrating last week at Government plans to slap a ‘sugar tax’ on soft drinks. But anyone now smugly sipping a Diet Coke and thinking that their sugar-free version – which will be exempt from the new levy – is doing their health any favours needs to consider the facts.

For while they contain no sugar, low- or no-calorie soft drinks made with artificial sweeteners won’t make you slimmer simply by virtue of their title. In fact, some studies suggest that those who choose diet sodas are more likely to be overweight than those who stick to the ‘full-fat’ versions. HOW CAN DIET SODA CAUSE WEIGHT GAIN? Diet versions of sugary soft drinks are typically made sweet with the addition of artificial sweeteners. Although often derived from natural sources, they are refined and chemically altered so that they taste hundreds of times sweeter, weight-for-weight, than table sugar, yet contain few or no calories.

There are currently five used in Britain: aspartame (by far the most common, used in thousands of products including Diet Coke and Diet Pepsi, and Canderel sweetener); saccharin (Hermesetas and Sweetex sweeteners, and used to sweeten ‘sugar-free’ fruit juices); acesulfame K (often blended with aspartame as it softens the slightly bitter after-taste); cyclamate (found in liquid formulations); and sucralose (Splenda).

Yet for some, far from aiding weight loss, choosing drinks or other diet foods containing these sweeteners may result in the opposite effect.

The San Antonio Heart Study examined 3,682 adults over an eight-year period in the 1980s and found that drinkers of artificially sweetened beverages consistently had higher BMIs.

And the American Cancer Society study, also conducted in the 1980s, looked at 78,694 women. After one year, regular artificial sweetener users were on average 2lb heavier than ‘non-users’.

Similar observations have been reported in children: a two-year study involving 166 youngsters found increased diet-soda consumption was associated with higher BMI scores at follow-up, indicating

HEALTH EDITOR weight gain. Meanwhile, the Harvard-backed Growing Up Today Study, involving 11,654 children aged nine to 14, also reported an association between diet soda and weight gain for boys, but not for girls. SO SWEETENERS ARE SOMEHOW FATTENING? No. Small-scale studies have suggested artificial sweeteners may exacerbate a ‘sweet tooth’: rats fed an artificial sweetener went on to consume more chocolate pudding weeks later than those that were fed a non-sweetened diet.

Sweet taste, whether delivered by sugar or artificial sweeteners, enhances human appetite too. So one theory is that sipping a drink laced with sweeteners only makes us more likely to reach for the biscuit tin.

Far more likely, though, is the ‘Big Mac and Diet Coke’ theory. Dr Aseem Malhotra, a cardiologist and spokesman for the National Obesity Forum, explains: ‘There is a health halo around these diet drinks. ‘People think that drinking them somehow has a protective quality or lessens the damage of a generally unhealthy lifestyle when they don’t.

‘Someone who has a flawlessly healthy overall diet and then has a diet drink won’t gain weight, but in reality this isn’t what happens.

‘People who go for these types of sodas are likely to choose other junk foods.’ I KNEW SWEETENERS WERE EVIL... Again, no. There is nothing inherently dangerous about sweeteners as chemical substances in themselves, despite what you may read. Aspartame, in particular, is mired in controversy, linked to everything from brain cancer to infertility.

Last year, Pepsi announced that it would be taking it out of its diet drinks range in the United States, although it is still used in the UK.

As Pepsi vice-president Seth Kaufman admitted: ‘Aspartame is the number one reason consumers are dropping diet soda.’

But as Dr Malhotra says: ‘The data isn’t conclusive. But when patients ask me “What should I drink?”, I say, “Stick to water.”’