Prof. Len Almond, Loughborough University
Part of the show Obesity, Appetite, Exercise and Weight Loss
Chris - Now let's talk about one way in which we can lose weight very effectively, and that's exercise. What is the contribution of exercise and to what extent can it really make a difference?
Len - Steve has mentioned energy balance, and that's an important concept to get over. What's also important in energy balance is the idea that people do more sitting than they actually realise. The average person does at least 90 per cent sitting throughout a whole day. We also tend to sleep far more at weekends. One of the reasons people tend to put on more weight at middle age is that from 35 years onwards, you start to decline in terms of functional capacity. What you also do is tend to do less activity at weekends, sleep and sit more, and this can add up to 17 kilograms over the amount of time Steve was talking about. So it's a very simple equation.
Kat - Some people like going to the gym, but some people just hate the gym. What's the best kind of exercise to take?
Len - By far the best and simplest thing is walking. We need to be walking at least 30 minutes every single day. Now that represents just two per cent of your day, whereas you will sit for over 90 per cent. I have some patients who sit for five hours every evening.
Chris - Can we put some figures on it? How many calories do you burn watching the telly.
Len - That's very difficult to say. If you want to lose two pounds in weight, you need to lose 700 kilocalories in a week. So we're talking about 500 kilocalories in terms of food each day and 500 in terms of exercise. Now it's quite easy to lose 500 kilocalories interms of food because you could just have an apple instead of an apple pie. But it's more difficult in terms of exercise. You need to get about 30 minutes of exercise in per day but you also need to reduce your sitting behaviour. That's an important factor.
Kat - There are some statistics here about the calories you burn doing different types of exercise. If you're an average 10 stone person, you can burn 370 calories cycling for an hour, 580 calories running for an hour, 330 calories downhill skiing, 266 calories weight training, about 400 doing aerobics, 140 doing yoga, 460 swimming, and having sex for an hour burns 360 calories!
Chris - I think it depends how active your sex life is though!
Kat - Yes, that's an hour not three minutes Chris.
Chris - Don't speak for your own standards Kat!