January 6, 2016

expert reaction to modelling study investigating reducing sugar in soft drinks, and obesity and type 2 diabetes in the UK

The possible effects of reducing sugar in soft drinks was modeled in a paper published in the Lancet Diabetes & Endocrinology journal, with the authors reporting that a reduction of 40% over five years would reduce obesity levels and cases of type 2 diabetes.

The SMC also produced a Factsheet on sugar and health.

Dr Ian Johnson, nutrition researcher and Emeritus Fellow, Institute of Food Research, said:

“This interesting study demonstrates the importance of sugar sweetened beverages as a source of excess calories in the UK population, and proposes a practical strategy for reducing their adverse effects on health by gradually reducing consumers’ preference for sweetness. It remains to be seen whether consumers would respond to the reduction in sugar content of beverages precisely as the theoretical modelling envisages, but this approach might well make a valuable contribution to a broad strategy for reducing excess energy consumption in the UK.”

Dr Nita Forouhi, MRC Programme Leader and Consultant Public Health Physician, MRC Epidemiology Unit, University of Cambridge, said:

“The proposed strategy offers a win-win for consumers, policy makers, the health service and also the manufacturers. Obesity and type 2 diabetes are major ongoing health challenges, and a combination of strategies is needed to tackle them as there are no single ‘one-size fits all’ solutions.

“This study is based on sound modelling that uses the best available nationally representative data sources, considering sales data, consumption data and accounting for wastage. As in any modelling, one can debate the assumptions, but they are clearly specified, the methods are transparent, different scenarios are tested and limitations and strengths are appraised by the authors.

“The study provides robust evidence, supported by past UK success for salt reduction, for a practical strategy that would see the gradual stepwise reduction in free sugars added to sugar sweetened beverages (SSBs). This in turn would contribute to lower energy intake from SSBs, leading to a meaningful reduction in overweight and obesity, and to obesity related new-onset type 2 diabetes in the long-term. Our own previous research has provided evidence that habitual daily SSB consumption is also related to future risk of type 2 diabetes independently of obesity, so the estimates in the current study may in fact be conservative.

“Substitution of sugary sweeteners with non-caloric sweeteners is an already available strategy, but the strategy proposed here to reduce energy intake from SSBs by gradually reducing the free sugar content is additionally attractive. Beverage sales and consumption data tell the story that many individuals and particular population groups preferentially choose the sugary varieties over and above the diet-zero calorie varieties. One can argue that they should cut their SSB consumption, but individual sustained behaviour change is perhaps the hardest goal to achieve, so changing the food environment is important. The authors pointed out that the amount of free sugars added to carbonated SSBs varies hugely from 3g to 53g per 330 ml regular serving size, so the scope for reduction of free sugar content is substantial. There is also ongoing debate concerning the evidence for the effectiveness of non-caloric sweeteners in managing obesity, and though unproven there are legitimate concerns that such sweeteners might change reward processing of sweet taste and might increase taste preference for very sweet foods. More research is needed in this area.

“Our own previous research led to the conclusion that substitution of SSBs with drinking water or unsweetened tea and coffee is associated with reduced risk of future type 2 diabetes, but we acknowledge that this may not appeal to all population groups and individuals. A range of options should be available, and a gradual reduction in free sugars in SSBs is certainly one.

“Following the success of the salt reduction strategy in the UK, the current modelling provides credible evidence to take the current proposed strategy on free-sugars reduction in SSBs seriously.”

Prof. Stephen O’Rahilly, Professor of Clinical Biochemistry and Medicine, and Director of the Metabolic Research Laboratories, University of Cambridge, said:

“It would be hard to argue with the broad conclusions of the Lancet Diabetes & Endocrinology paper by Ma and colleagues who suggest that if we consumed less sugar in the UK the prevalence of obesity and Type 2 diabetes would fall. However this is a purely theoretical study and there are many assumptions made which reduce confidence in the statements regarding the precise extent of the health benefit.

“Ma et al dismiss strategies which would involve replacement of sugar with artificial sweeteners. However, the best quality evidence currently available indicates that artificial sweeteners do not significantly contribute to human obesity or diabetes. Replacement of sugar with a substitute sweetener would be predicted to be equally effective at reducing the incidence of these diseases. Artificially sweetened beverages might be more attractive to current consumers of sugared drinks than non-sweetened ones. It might also be easier to incentivise companies to change the emphasis of their manufacturing and marketing toward versions of their current products that contain non-caloric sweeteners rather than to unsweetened drinks such as bottled water.”

‘Gradual reduction of sugar in soft drinks without substitution as a strategy to reduce overweight, obesity, and type 2 diabetes: a modelling study’ by Yuan Ma et al. published in the Lancet Diabetes & Endocrinology on Wednesday 6 January 2015. 

Declared interests

Dr Ian Johnson: Ian Johnson is an Emeritus Fellow at the Institute of Food Research and was a member of the SACN Working Group on Carbohydrates and Health. He currently has no research grants or commercial affiliations.

Dr Nita Forouhi: “I have no conflicts of interest.”

Prof. Stephen O’Rahilly: “I have not consulted with, collaborated with nor received any payments from any companies that manufacture beverages.”