HM: My name is Hazel Morris and I'm at the Medical Research Council Clinical Sciences Centre to talk to Professor Jimmy Bell. His work measuring fat and where people store it has created a stir in the health pages in the last few months so I'd like to know a bit more. Professor Bell, what are you researching?
JB: Our group is interested in understanding the genetic and environmental factors that determine not only how much fat we put on, but also where we put it on. So we started this work many years ago, the first thing that we did was to actually implement enviro imaging methodology to actually look at fat directly. We decided to use magnetic resonance imaging to literally do a 3D map of the body that would allow to quantitate the total amount of fat in any part of the body, including within organs, like for example the liver, the heart, muscle, pancreas and so forth. And even to our own surprise it was actually very revealing because very quickly it became clear that there was a sub group of people that were relatively slim; they were the right BMI, the were the right size but yet they had lots of internal fat, lots of fat around the organs and also fat within the liver and the muscle. And then there was another sub group, much smaller, where they had a lot of external fat but internally they had very, very little fat. Almost a hidden epidemic of people supposedly slim but yet fat inside and the other sub group of people who are kind of fat outside but thin on the inside.
HM: If you were a relatively slim person, with maybe say an inch of fat on the outside of your body, would you then have a quarter of an inch of fat on your organs? Is that the kind of relationship?
JB: Well we were expecting that there is a ratio between internal and external fat that we thought would stay more or less constant. What was surprising to us was that there were people who actually had very little external fat but there were absolutely covered inside with fat and that was very surprising.
HM: Is it more common in men than in women?
JB: Well we don't actually know at the moment but we do see it more often in men than in women. We do see it women especially those who tend to yo-yo diet. When they yo-yo up they put most of the weight back on as fat, so every time you yo-yo you're actually ending up with a higher and higher percentage of body fat, even though you might end up with the same body weight. HM: So what do you think the health implications are for that overall?
JB: The risk of developing certain disease increases and this is a long term time bomb that people are carrying. As you grow older that amount of fat will increase and will increase and the problems related to that fat will become more and more acute.
HM: So I would imagine if you are a slim person you might not think I'm at risk of developing type 2 diabetes because I don't have that body fat. JB: Absolutely and that's why when people go to the gym, they tend to be disappointed, they go to the gym for a year and they feel “oh I'm the same shape, I'm the same size and I weigh the same, what's the point?” They don't realise the clinical and health benefits. HM: So what would you say to somebody who might be listening to this and think perhaps I've got a lot of fat on the inside? JB: We don't want people to be frightened and stop eating everything and they start going mad and going to the gym everyday or whatever. The important thing here is lifestyle and lifestyle choices. There are no short cuts when it comes to health. One of the things that we're trying to work out is going to the gym of having a physical activity a life sentence? So are we supposed to be doing this for ever more, which is what frightens everyone, because people think “oh my god, I'm going to have to go and do this…” So part of our study here at the MRC is trying to see what type of exercise will maximise the benefit of that physical activity. Do we have to do it every week or can we do it for example for a month and then have two months off or so forth, or do you have to do it every day? Trying to actually unravel that is very important so we can actually tell the general public “look, if you want to maximise the health benefits of a lifestyle choice, this is what you can do to get away and still be healthy.” HM: Hazel Morris JB: Jimmy Bell
