Jamie Oliver’s sugar levy trial in his eponymous restaurant chain has failed to convince experts.
37 restaurants were involved in the trial, but researchers warn that the results are too scattered and small to represent real data.
Trail in Jamie’s Italian
37 Jamie’s Italian restaurants took part in the trial, which saw a 10p levy introduced on sugar-sweetened beverages. Those in food jobs may know already that they are often referred to simply as SSBs.
After 12 weeks of the levy being introduced, a decline of 11% in sales of SSBs per customer was observed. This dropped to 9.3% after six months.
The study, which was led by the London School of Hygiene and Tropical Medicine, was the first research done in the UK into the effects of raising the price of SSBs in a restaurant setting. It was funded by the National Institute for Health Research with participation from the University of Cambridge.
This is part of a larger campaign which celebrity chef Jamie Oliver has been engaged in for much of his career. He first tackled school lunches, insisting that children should be getting food with better nutritional values during their years of education. The sugar tax is his newest target, as he believes that forcing people to pay more for unhealthy food will convince them to take the healthier route where it is available.
Experts remaining sceptical
However, the research is not conclusive enough for scientists to agree that a direct link has been found.
Susan Jebb, professor of diet and population health at the University of Oxford, pointed out that the research used a “pragmatic interrupted time series”, which is not the strongest of research designs. This, she said, means that the findings are “indicative rather than conclusive”.
Richard Tiffin is the director of the Centre for Food Security at the University of Reading. He says that the price change was not high enough, and the drop in consumption levels not low enough, to prompt any significant change in the UK’s obesity rates.
He said, “Measures that are specifically targeted at those with the worst diets are likely to be more effective.”
This is a fair point to make. After all, the menu at Jamie’s restaurant chains does tend towards the healthier side, although plenty of the menu items are still full of fats, sugars, and calories. The price range of the items on the menu also means that diners tend to be from middle-class backgrounds, rather than the lower-class environments which tend to engender the worst diets.
There is even some doubt that the studies’ results can be take seriously. There was a lot of publicity surrounding the launch of the trial, which means that some diners went in knowing ahead of time that they were being discouraged from going for SSBs.
Those who are involved in food finance jobs will be familiar with the many phenomena which can cause sales to rise and fall on certain menu items, sometimes even without explanation.
Kevin McConway, emeritus professor of applied statistics at the Open University, says there is cause to doubt that the drop in sales “was entirely, or even mainly” caused by the raised prices.
At the moment, it seems that we cannot draw much of a conclusion from Jamie’s trial. What is required next is a larger scale trial – and perhaps this will come in the from of an additional sugar tax imposed by the government, which has already targeted sugary foods in shops. If the regulation proves to have littler or no effect, it is easily undone with a change of regime.