diet-cokeIn a commentary on current research and policy into sweetened drinks, academics from Imperial College London and two Brazilian universities (University of Sao Paulo and Federal University of Pelotas) argue that sugar-free versions of drinks may be no better for weight loss or preventing weight gain than their full sugar counterparts, and may also be detrimental to the environment.

Professor Christopher Millett, senior investigator from Imperial’s School of Public Health, said: “A common perception, which may be influenced by industry marketing, is that because ‘diet’ drinks have no sugar, they must be healthier and aid weight loss when used as a substitute for full sugar versions. However we found no solid evidence to support this.”

Professor Millett and colleagues outlined current evidence of the health effects of consuming artificially-sweetened beverages (ASBs). Although there was no direct evidence for a role of ASBs in weight gain, they found that there was no evidence that ASBs aid weight loss or prevent weight gain compared with the full sugar versions. In addition, the production of ASBs has negative consequences for the environment, with up to 300 litres of water required to produce a 0.5 L plastic bottle of carbonated soft drink.

Professor Carlos Monteiro, co-author from the University of Sao Paulo, warned: “Taxes and regulation on SBS and not ASBs will ultimately promote the consumption of diet drinks rather than plain water - the desirable source of hydration for everyone.”

Professor Russell Viner, Officer for Health Promotion for the Royal College of Paediatrics and Child Health (RCPCH), was keen to substantiate the claims, saying: “As this paper acknowledges, the effect of artificially sweetened beverages on weight and other health outcomes, especially for children, is inconclusive. And although plausible, many of the researchers arguments are theoretical and cannot be substantiated with existing data.

“What we do know though is that regardless of any impact on weight, reducing sugar intake will have beneficial effects on dental health which is particularly important in children. Currently 25% of five-year-olds have obvious tooth decay, with an average of more than three missing, decayed or filled teeth. Government’s fizzy drinks tax comes into force next year and with robust monitoring, we should be able to see what happens regarding the consumption of artificially sweetened beverages and substitution effects, as well as the impact of weight and obesity.

“No fizzy drink, diet, sugar free or full fat provide any nutritional value whatsoever so in reality, it is better to avoid them altogether. However, we know that people like fizzy drinks and will continue to drink them if they are available, so until we have conclusive research on the health implications, I would suggest opting for a sugar-free alternative as we know this is most certainly better for children’s health.”

Dr Alison Tedstone, chief nutritionist at Public Health England, commented: “Our extensive evidence review showed swapping to low or no sugar drinks goes some way to managing calorie intake and weight.

“It’s especially so for young people as they consume three times the amount recommended, mostly from soft drinks. However, maintaining a healthy weight takes more than just swapping one product for another. Calories consumed should match calories used, so looking at the whole diet is very important.”

The paper, published in the journal PLoS Medicine, can be viewed here.