The government’s recently introduced tax on sugary drinks is good news. It underscores that sugar is bad for your health. It remains to be seen if higher prices reduce sales or whether manufacturers will find artful new packaging formats to keep us glugging it down. But I’m dismayed by how sugar-free ‘diet’ drinks made with chemical sweeteners are still presented as healthier alternatives.


Synthetic sweeteners do indeed deliver a sweet hit minus the calories, and the assumption has been that excess calories make you fat, irrespective of source. By this thinking, however, the calories in an avocado can be just as bad for you as those in confectionery. I find this notion preposterous. But the alarm bells around artificial sweeteners ring loudest because they’re sweeter than sugar by 200 to an unimaginable 37,000 times – so how can they help to curb our national sweet tooth?

Studies link artificial sweetener to a variety of negative health outcomes but the European Food Safety Authority has ruled that all those for sale in the European Union, although potentially toxic in larger quantities, are ‘safe for human consumption at current levels of exposure’. I don’t know about you, but to me that falls short of a ringing health endorsement, especially for people who drink gallons of the stuff.

Glass box of colourful artificial sweetener sachets

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Study after study highlights negative health effects. This spring, for example, one Boston University study concluded that artificially sweetened drinks significantly raised the risk of stroke and dementia. No such association was found with sugar. But even more incredible is the body of evidence now showing that synthetic sweeteners don’t actually help to control weight.

One animal study found that rats that were fed artificial sweeteners gained weight faster than those eating sugar. A major review of research in 2013 concluded: ‘Accumulating evidence suggests that frequent consumers of sugar substitutes may also be at increased risk of excessive weight gain, metabolic syndrome, type 2 diabetes, and cardiovascular disease’.

Given that artificial sweeteners are calorie-free, how could they make us fat? One theory is that a sweet taste, unaccompanied by calories, sends the body hunting for those calories, encouraging over-eating; you choose the ‘diet’ drink then eat the doughnut. Another possibility is that because the synthetic sweeteners awaken the brain’s pleasure centre but don’t deliver the anticipated calories, they upset our appetiteregulating hormones, making us more liable to overeat.

The more research that’s done on artificial sweeteners, the more I’m convinced that switching to these from sugar is a case of ‘out of the frying pan into the fire’. They have a bad, bitter, tinny taste too – some manufacturers try to hide it by using what’s known in the industry as ‘masking’ flavourings.

If sugar warps our palates, then hyper-sweet synthetic substitutes certainly do. We must re-educate our tastebuds to expect lower levels of sweetness, not replace them with more intense new ones

Filling a glass of cola next to pile of sugar cubes

Tips for un-sweetening drinks

  1. Offer free tap water in public places like schools to help kids stay hydrated and alert.
  2. Add slices of lemon, orange or mint leaves to water to coax those who don’t like it plain.
  3. Try kombucha. The sugar used to make it is used up by fermentation, and it’s good for the gut.
  4. Make your own drinks, so you know how much sugar is in them. Try to cut it down progressively.
  5. Dilute fruit juice so the drink is at least 50% tap water.

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Good Food contributing editor Joanna is an award-winning journalist who has written about food for 25 years. She is also a regular contributor to BBC Radio 4.

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