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A study in the BMJ suggested a 20% tax on sugar sweetened drinks would reduce the number of UK adults who are obese by 180,000 and who are overweight by 285,000.
Prof Sir Stephen O’Rahilly, Professor of Clinical Biochemistry and Medicine, University of Cambridge, & Director, MRC Metabolic Diseases Unit, Wellcome Trust-MRC Institute of Metabolic Science, said:
“Obesity is the result of a chronic excess of calories ingested over calories expended. Anything that facilitates increased calorie intake will increase the risk of obesity. Sugary drinks are certainly part of the problem as they provide “unnecessary”, if pleasurable, extra calories. Whilst any effective discouragement to the ingestion of sugary beverages would likely have a health benefit on society, taxation of specific foods is likely to be currently politically undeliverable in most democracies. A workable alternative might be to encourage the major companies to switch to the aggressive promotion and marketing of less harmful versions of their products. This could be achieved by balancing a 20% tax on sugared products with a 20% subsidy on artificially sweetened versions of the same beverages. While there is a lively debate about possible adverse effects of various non-caloric sweeteners they appear broadly safe. If, as seems likely, people’s desire for these type of beverage continues unabated, this may be a superior alternative to the continuous ingestion of unnecessary calories as sugar.”
Prof Brian Ratcliffe, Professor of Nutrition, School of Pharmacy and Life Sciences, Robert Gordon University, Aberdeen, said:
“This paper is an interesting modelling exercise but the authors make several assumptions that may not hold true. They give five reasons why a tax on sugar sweetened drinks (SSD) may be an effective measure to improve health. The second of these assumes that SSD will not be replaced or compensated for by consuming other foods so that reductions in energy intake are expected. The authors’ fourth reason also discounts the possibility of this kind of compensation by assuming that SSD would be replaced by ‘healthier’ drinks (diet drinks, fruit juice, milk, and water) rather than consumption of foods. This is the basis of what the authors refer to as ‘Modelling step 2’. But other studies including some recent ones have shown that such compensatory changes can occur, meaning that the predicted reductions in energy intake and the consequent reductions in overweight and obesity may be overly optimistic. The authors’ reasoning that SSD are non-necessities and contain no beneficial nutrients, so direct harm from reducing consumption will not occur, is fair enough but while the projected benefits of a 20% tax on SSD look impressive in absolute terms (the reduction in numbers of obese and overweight persons), they are paltry when considered in percentage terms (reduction in prevalence of 0.9% for overweight and 1.3% for obesity). Politicians, however, may find the predicted £276 M annual revenue increases the attraction of this kind of taxation.”
Prof Tom Sanders, Professor of Nutrition and Dietetics, School of Medicine, King’s College London, said:
“I think this paper is very naïve in believing that calorie intake is so easily manipulated by punitive taxation. The assumption at the centre of this article is that 20% increase in tax (they already attract 20% VAT) would significantly reduce consumption and therefore decrease calorie intake. Most nutritionists agree it would be better to drink water than sugar sweetened beverages. However, many consumers like sweet drinks and if they could not afford to buy sugary fizzy drinks they can always revert to drinking tea with added sugar as in the past. The cost of sugar sweetened beverages is currently so low that any price increase would be so marginal that it would be unlikely to affect intake. You can buy 3 litres of orange squash (28% sugar) for £1 in discount stores.
“From my viewpoint, sugar now seems to be the new tobacco for the British Medical Association and the publication of this article by the BMJ seems to be part 2 of the campaign in its “war against sugar” launched last week by Dr Malhotra in the BMJ (BMJ 2013;347:f6340). However, sugar sweetened beverages only contributes to obesity if they provides extra calories on top of usual diet. Furthermore, there is no reliable evidence to show that sugar itself is more fattening than other carbohydrates on a calorie for calorie basis or specifically linked to risk of type 2 diabetes. In the UK, sugar sweetened beverages are not associated with obesity to the same extent (if at all) as in the USA, where intakes are much greater. Furthermore, the rolling programme for the National Diet and Nutritional Survey shows a trend falling intakes of non-milk intrinsic sugars see http://www.foodafactoflife.org.uk/attachments/8921d124-960e-4f68d4b026f4.pdf.”
Catherine Collins, Principal Dietitian at St George’s Hospital NHS Trust, said:
“It’s a persuasive argument made by the AMRC and Sustain that adding 20% tax to sugary drinks would reduce intake, calories and have a modest effect on reducing obesity in the UK population. As a dietitian keen to get people to substitute calorie free versions for full sugar drinks, I think that point-of-purchase 14p price difference between, say, a 70p can of diet cola and an 84p full-sugar version next to it in the chill cabinet would be the ‘carrot’ to make people choose lower calorie versions. This would be particularly helpful for those buying the multipack versions of 4x2l soft drinks, or cases of 24, where the price differential would be far more noticeable.
“But, and it’s a BIG but, would this added tax help the obese to lose weight, saving money and healthcare resources in the process as claimed by the authors? As a dietitian working with the public about dietary issues day in, day out, I really think not. Possibly for those ‘cola addicts’ who regularly consume perhaps 4l a day, but as a dietitian I’d be keen to get them to think of other low calorie options such as carbonated water, water, tea or coffee, and use other options (e.g. CBT) to address why they have this dependent behaviour.
“For the rest of us, sadly, I think this approach would have very little impact on adult weight management. Why? Because government data shows that the incidence of obesity rises with increasing age, peaking in the 45-74 age group. Waist size, a marker of central obesity associated with health risks such as diabetes and heart disease also rises (1). Yet the NDNS study quoted by the authors to justify their stance shows quite clearly that both types of sugary drinks are consumed far, far less as people get older – less than 50kcal (2) a day is consumed from the drinks targeted by this approach, compared to around 120kcal intake from both types of drinks in younger adults (3). So very little calorie reduction would take place in the older age groups who would benefit most from losing weight.
“Finally, can substitution of low calorie drinks, whilst a worthwhile objective, actually alter overall calorie intake and help arrest obesity? I think from our current knowledge of human behaviour it is highly unlikely, except in the extreme drinkers. Human food and drink intake is dependent on many, many variables, of which money to spend is just one aspect. Attitudes, behaviour, reward, pleasure, as well as hunger, appetite and normal daily food and drink choices all influence. In this quite recent paper by Hull university researchers, adding sugar to the diet in drink form can adjust appetite and calorie intake to a quite significant degree (4). There are papers that show fruit juice, rather than soft drinks, to be a major contributor to childhood obesity (5), whilst studies on high school children showed that as calorie intake from soft drinks reduced, intake from other foods went up (6).
“In summary, eating is complicated. I think the tax ‘stick’ would beneficially reduce consumption of sweetened drinks, but it’s a whole staircase of steps too far to presume such tax would influence obesity in the UK population.”
References from Catherine Collins
(1) Adult slide set from the Govt National Obesity Observatory (now part of NHS England), slide 9 refers http://www.noo.org.uk/slide_sets slides 17 and 18 show link with waist size with increasing age
(2) Authors quite often like to use the actually more correct Kj than Kcal. There is 4.2kJ in one kcal, so the numbers look much worse. See table 1 in the paper
(3) From table 1, it’s clear that as age increases, intake of sugary drinks goes down, but tea and coffee gradually increase. Of course, these have zero calories, as mentioned in the table. However, it is not uncommon for consumers to add sugar to their drinks, or a flavoured syrup. Both these forms of added sugar ARE NOT picked up by the NDNS survey, and I think are more relevant as people age than the sugary squash and fizzy drinks argument.
(4) http://www.eurekalert.org/pub_releases/2013-10/snu-owa102813.php seems to be sponsored by sugar industry BUT if the research is sound there is no reason to dismiss this.
(5) 2012 http://www.ncbi.nlm.nih.gov/pubmed/22813423
(6) http://www.ncbi.nlm.nih.gov/pubmed/19166676 modest reduction in sugar-drink calories, made up elsewhere.
‘Overall and income specific effect on prevalence of overweight and obesity of 20% sugar sweetened drink tax in UK: econometric and comparative risk assessment modelling study’ by Briggs et al. published in the BMJ on Thursday 31 October.