Hero to zero – sugary drinks

Logically, it seems like a good idea to switch from sugary drinks to versions made using artificial sweeteners. You get the same sugary taste without the calories, which should help you lose weight as part of a calorie controlled diet. Sugar-sweetened beverages (SSBs) such as soft drinks, fruit-flavoured drinks, and sports drinks, make up a third of UK teenagers’ sugar intake, and nearly half of all sugar intake in the US.

High sugar diets have been blamed for the huge increase in the number of people with Type 2 diabetes and obesity in the UK and around the world. The so-called Sugar Tax, due to come into force in April 2018, is the Government’s response to the problem and will add as much as 24 pence to a litre of sugary soft drinks.

Unfortunately, the logic of switching from sugary drinks to artificially sweetened versions may not be such a good idea after all. In fact, when our team at Imperial College, London, reviewed the evidence, along with academics two Brazilian universities (University of Sao Paulo and Federal University of Pelotas), we found that sugar-free versions of drinks may be no better for weight loss or preventing weight gain than their full-sugar counterparts. There is also no solid evidence to support the claims that they are any better for health or prevent obesity and obesity-related diseases such as type 2 diabetes.

In fact, some studies in animal models have shown a link between artificially sweetened drinks and type 2 diabetes. The studies are inconclusive but there is definitely a concern that these chemicals can kick start similar processes that lead to metabolic disease. We are still trying to understand the potential mechanisms behind this and further studies are needed.

The reasons why artificially sweetened drinks seem to fail to prevent weight gain are complex, but the easiest explanation is that people who swap sugary drinks for the diet versions simply compensate with other sugary and fatty food. There seems to be a widespread idea that ‘I’ll have the low-cal drink and a bigger burger’. Also, the artificially sweetened drinks may continue to drive a pre-existing craving for sweet things and there is no opportunity for someone to change their tastes and habits.

One of our concerns is that the upcoming Sugar Tax will not include artificially sweetened versions, meaning that they may become cheaper and more ubiquitous than they already are. Low-cal drinks currently comprise a quarter of the global sweetened beverages market. People should be advised that the jury is still out as to whether long-term consumption of these drinks are good for your health, especially in large volumes.