Nudges towards and away from obesity

Interviewer: Andy Tootell (Ideas Lab)
Guest:  Dr Frank Eves
Recorded: 23/05/2012
Broadcast: 11/06/2012

Intro VO: Welcome to the Ideas Lab Predictor Podcast from the University of Birmingham. In each edition we hear from an expert in a different field, who gives us insider information on key trends, upcoming events, and what they think the near future holds.

Andy: Hello, today I’m with Dr Frank Eves who’s a Reader in Lifestyle Physical Activity at our School of Sport and Exercise Sciences. Hello Frank. 

Frank: Hi there. 

Andy: So a Reader in Lifestyle and Physical Activity. What’s all that about then?

Frank:  Another way you could describe me is I’m a public health psychologist, so I apply psychology to issues in public health. Now, most people will know, obesity is a growing problem in the Western world and of course physical activity, in other words being active, is one approach to this problem.  And it’s not about sport. You can’t do sport every hour of the day and so the net outcome is if you look at what is effecting energy expenditure, it’s the activity you do as part of life. Now the current guidelines are for doing a minimum of 30 minutes of brisk walking for example, five or more days of the week. That’s the current guidelines. Now when you look at how we do this in England, when people report how much they do, 39% of men and 29% of women say they do sufficient activity. When you objectively measure this with motion sensors you find that 6% of men and only 4% of women are actually sufficiently active so you can see, coupled with food and a drop in activity, you can see why obesity is growing. 

Andy: One of the current approaches by the British Government to fight obesity is in the form of ‘nudges’. Can you explain a little bit more about what those are?

Frank: OK, I’ll give you two examples.  I mean one is to redesign the environment to make people more likely to be physically active. So for example, if you think of a train station, if you reach the stairs before you reach the escalator when you want to leave the station, you’re more likely to take the stairs.  Another way, we sort of estimated what would happen if you increase the width of the stairs because when you think of a station, lots of people are trying to leave it at once and they’re going to take the quickest route out of the station. If you double the width of the stairs you get a 17% increase in stair usage and that’s a daily increase.  Now, you probably think climbing stairs is quite pointless. What’s that going to do for obesity?  But an 80kg man, so somebody overweight, who just went upstairs in their normal house ten extra times a day, over a year they’ve expended energy equivalent to 3lbs of fat. So if you’re talking about preventive effects then what you’re doing is by incorporating activity into your daily life you’re actually burning calories which are combating what you might be getting extra in terms of food.    Another way is if you think about food, I mean most people wouldn’t realise this but the items at the start of a menu and the items at the end of a menu are twice as likely to be chosen as the items in the middle of the menu. So, if you put the low calorie items at the start of the menu and at the end of the menu, you’re going to make people more likely to choose something which has got lower calories.  These are simple, these are passive environmental nudges that push you in one direction, or at least make you more likely to make a choice in one particular direction.   But there are also active approaches. So, for example, most of us don’t know the amount of calories in food and this is not just the lay public, this is also true of nutrition experts who just don’t realise how many calories there are in food and so if you’re talking about an active nudge, what you’re doing is you’re labelling items at the time people are making a choice so that you’re informing choice.  So, if you let people know the calories you’re not forcing them to not eat chips for example but you’re letting them know that should they choose this portion of chips, that’s exactly how many calories it would be.  When you give people this sort of information you find they typically will choose less calories.

Andy: I mean Sainsbury’s started doing that wheel didn’t they with the red segments and the green segments and that kind of thing.  I mean that’s quite informative. I don’t know what you think of that? 

Frank: Yeah, yeah, a simple traffic light system is very plausible because people understand it, but of course I think what’s actually happening is that the food manufacturers would much rather that you chose what they would like you to choose and so they’ve gone for a much more complex labelling system. So for example, if you look at the amount of calories in a pizza, they will give you the calories per quarter pizza as well as the calories in the whole pizza. 

Andy: Yes!

Frank: Because you sell a lot more food if it’s higher in calories because it’s more palatable, it’s really that simple.  I mean I think unfortunately the food manufacturers are not our friends. Now, if we’re thinking how we’re going to deal with this then it really has to be legislation at the Government level and that’s really quite a difficult nettle to grasp. So for example, if you think of physical activity, make parking more difficult and more expensive and people will walk.  It’s really simple but of course what you’ve got set against that are people don’t want to do that and of course you’ve got all the people who are busy selling cars that also don’t want that to happen. This is not simply a question for health professionals, it requires everybody to be involved in this. 

Andy: Yes. 

Frank: And it’s no good blaming people for being fat when of course you allow food manufacturers to befuddle their choices by giving them difficult information to absorb.  It’s not that they’re giving them misleading information but they’re giving them difficult information. 

Andy: When we’re talking about food, these are choices that people are aware that they’re making but are there any other processes that are going on?

Frank: To explain this I have to talk about something called embodied perception. Now what that means is your perception of the world is actually influenced by your physiological state.  So we tend to think that what we see is actually accurate and we don’t think that it’s influenced by what’s going on in our senses and inside us. So to give a lovely example, a delightful study by Simone Schnall, what she’s got people doing is they’re making moral judgements and the judgement here is whether you should be allowed to have sex with your first cousin.  Now most people don’t agree with that. They’re doing this sitting in a cafeteria, making these moral judgements and unbeknownst to them, she’s actually sprayed something called fart spray on a nearby bin. 

Andy: [laughing] 

Frank:  Now, what happens is people can smell the spray but don’t think it actually influences their judgements.  What happens is, if you disgust people with a bad smell, they make more severe moral judgements, you know. 

Andy: Really?

Frank:  So the point is that our conscious perception is not unmaleable. It’s not veridical; it’s influenced by our physiological states.  So why is this important in terms of physical activity and in terms of obesity?  Well, when you’re hungry, what happens is that parts of your brain light up, in other words become much more interested in food cues and in particular they’re interested in high density things like chips and cakes rather than salads and so the point is that when you’re hungry you will be drawn towards things which are high in calories. So, your internal physiological state of hunger will influence the choice that you made over and above what you might be doing in terms of health. So you may be trying not to eat chips but of course when you’re hungry, your body is asking you to eat chips as opposed to eating salad because that would suit the body better rather than what suits the health of the nation better.  Another example, if you think of physical activity, if you’re tired or if you’re carrying a bag, then hills actually look steeper and the reason for that is that you’ve got reduced resources to climb that hill and so in some way those reduced resources that you have in your body influence your perception so when you ask people how steep does that hill look, it looks steeper.  So what we find is not only does carrying a bag or being old make the stairs look steeper but they also look steeper to people who are overweight. 

Andy: So how does this all fit with current approaches to health promotion?

Frank:  If you think about it, what we’ve got is the Government and health professionals encouraging us to be more physically active and to actually choose less rich in calories food. But of course what we’ve got is something else. We’ve got a system in our body which is making choices independent of what we might want to do for health and so what that’s trying to do is trying to minimise the energy cost of getting around, so it’s trying to put us off being physically active and it’s trying to make us select high density foods – in other words, foods with lots of calories – because that will be advantageous for it.   So there’s this kind of interplay between two systems continually when you’re looking at health promotion.

Andy: Dr Frank Eves, thank you very much for joining me today.

Frank: Yeah, thank you very much. 

Outro VO: This podcast and others in the series are available on the Ideas Lab website: On the website, you can find out how to e-mail us with comments, questions or suggestions for future topics for the podcast. There's also information on the free support Ideas Lab has to offer to TV and radio producers, new media producers and journalists. The interviewer and producer for the Ideas Lab Predictor Podcast was Andy Tootell.