Toni Steer, MRC Human Nutrition Research Unit
This week, UK politicians unveiled plans for a tax on sugary drinks, aiming to reduce the level of obesity in children. Nutritionist Toni Steer explained how it is supposed to work, and why it is controversial, to Chris Smith...
Toni - Well what the government want to do, they want to introduce a levy onto soft drinks. So what they want to do is introduce this levy for about 2018 and itís to do with the amount of sugar per litre or per 100mls that in soft drinks. So they want to tax the industry which means that thereíll be; I think it's around 5 grams per 100msl at a lower level and I think 8 grams per 100mls at a higher level. Itís sort of in that region. Now this is the idea that they want to try and tackle our consumption of soft drinks because weíve got a lot of evidence to show now that actually, sugar-rich drinks, not only are bad for your teeth and dental health but, actually, what they tend to is they undermine your appetite control. So the liquid calories that you have in soft drinks donít seem to register very well that youíve consumed them and if you consume excess calories in liquid calories, you consume more calories you gain weight.
Chris - We did a demo on this programme actually, where Giles Yeo who works on how the brain decodes how much energy youíre taking into your body, gave me a bunch of apples and said youíre going to eat the number of calories that had gone into what Iím going to drink and weíre going to see who gets there first. He drank the equivalent of the apples as juice and I had to eat them. He finished off half a pint of apple juice and that was the equivalent of six apples and Iíd managed two apples in the time it took us to do that. I mean thatís the point heís making, itís very easy to put a lot of calories in very quickly.
Toni - Itís really easy to consume excess calories in that liquid form so looking at our concern around obesity and overweight, this is one of the ways that we want to try and create an environment that perhaps makes soft drinks less desirable.
Chris - Havenít people always eaten sugar Toni? This isnít a new thing. Weíve had people eating honey and so on for thousands of years.
Toni - We have but I think itís much more prevalent. If you look at the number of processed foods we have; it you look at the availability of soft drinks, sugar rich drinks, weíve got them readily available in supermarkets open 24 hours a day, 7 days a week. Itís really easy to get those kind of high sugar type food and drinks. In terms of the sugar tax, it's actually really difficult to know when they roll it out what the impact will be. One of the things that might happen is that manufacturers may be encouraged to reformulate their soft drinks which would then get them down to a lower tax levy.
Chris - One politician said all it will do is encourage some people to switch to the cheaper, nastier brands that are cheaper to start with but with just as much sugar but, even with the levy on, they become the price of the more expensive brand they prefered before.
Toni - Itís really difficult to know how itís going to roll out because the other way is that actually what might happen is that the industry may absorb that tax increase and what youíll see is that there may even be an increase on all drinks across that product range.
Chris - Theyíll say we know it bad but weíre just going to make you live with it because you like it.
Toni - If all the soft drink prices go up that may result in some people perhaps not choosing them..
Chris - What about if we look at other things. Because weíve had the salt lobby - have tried to get down the amount of salt in food. Weíve also had fairly punitive taxes in some countries applied to things like cigarettes and alcohol. Is there any evidence these sorts of carrot and stick maneuvers work?
Toni - I think there was some evidence. I know that they cite stories a lot from Mexico where they introduced this sugar tax, and I think that there was some evidence that in some groups of the population, you did get people not buying them and perhaps choosing the diet versions and I think for it to work, what the public need to see is a really clear price differentiation between the high sugar drinks and the no sugar drinks and once you see that it begins to make the choice a lot more obvious. So how this will roll out in reality we donít really know but I think once of the important things is good surveillance so that we can monitor what the kind of consumption patterns are over the next few years and thatís one of the things that we do in our unit actually, we do one of the nutrition surveys. So itís difficult to know but what we have to remember is that this is just one part of tackling the obesity epidemic. Itís not the solution but if we have a whole range of things, eventually it helps create that better environment that helps encourage people to make better choices because itís really difficult for individuals. Weíre living in an environment that makes it so easy to choose and consume these foods.
Chris - It sadly does. Chris?
Chris Basu - This might open a can of worms. Are diet drinks any more safe than normal sugary drinks?
Toni - I think what you might be citing or thinking about is there have been some studies, I think there was a particularly notable one that was carried out somewhere in Italy in rats looking at artificial sweeteners and whether actually, excessive amount of artificial sweeteners may cause or increase the risk of cancer. I think what theyíve found is they did see this increase with the artificial sweeteners in this cancer risk but you have to remember that the rats were given these doses of carcinogens which put them at risk of developing cancer anyway. And I canít quite remember but I think it was something like the rats were drinking an equivalent of about 300 cans of coke a day. It wasnít quite the realistic way that you would replicate it in a human study. I think there was some evidence but not enough
Childhood obesity and diabetes is/have been on the rise.
The problem with diet soft drinks is that they reset your body's threshold for insulin secretion thereby promoting insulin resistance and diabetes. The sugary taste tells your body to prepare to handle a large caloric load by secretion insulin. When you get the taste of sugar without the calories, your body adjusts over time and increases the sweetness level at which it will secrete insulin. And next time you get a dose of real sugar, your blood sugar level will go up higher before insulin kicks in. Adel, Thu, 24th Mar 2016