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The BMI Lie? It's the magic number that tells you whether or not you're a healthy weight, but could it be a big fat sham?Tubby Tom?Big Brad?


Would you describe Tom Cruise, Brad Pitt or Jonny Wilkinson as overweight? We didn't think so. But, according to their BMI numbers, that's exactly what they are.

The BMI system, devised 150 years ago, uses your weight and height to calculate an estimate of body fat.

It gives you a number that falls into one of the following categories: underweight, healthy, overweight, obese and very obese.

Despite all the scientific developments since the 1800s, we've stuck with this old theory and it has become the accepted way to work out whether or not we have a healthy weight, used in hospitals, doctors surgeries and slimming clubs.

In recent years it's even featured in fitness computer games, such as the Wii Fit, which encourages players to weigh themselves every day and tells them where they fall in the BMI scale.

But some health experts say the measurement isn't everything it's cracked up to be it could even be called dangerously misleading.

Firstly it doesn't take into account each individual person's body shape. Being healthy isn't just about the amount of fat you have, it's about where it's stored on your body.

For example, fat cells around the tummy pose a higher health risk than those on the thighs or hips. In fact, having a waist of more than 88cm (34.6inches) for women and 102cm (40.2 inches) for men indicates a heightened risk of cardiovascular and metabolic disease. So, people with smaller waists are healthier, which won't show up on the BMI.

Personal trainer Barry Stalker ( doesn't consider the BMI when training his clients. 'It's a totally outdated system. When clients come to me, they talk about BMI and I tell them to forget about it. It's all about the individual person,' He says. 'I'm 6ft and very muscular so I'm overweight, nearly obese, according to my BMI but I couldn't be fitter.

'I train a bloke who's 6ft 3in and was quite fat when he came to me. He's now lost the fat but gained muscle. He's much healthier but his BMI hasn't really shifted to reflect that.'

This is the other main problem with the BMI - it can't tell the difference between fat and muscle. It presumes that any excess weight is fat, rather than muscle. And, since muscle is denser than fat, many physically fit people are mistakenly classified as 'overweight', while they are actually less likely to die young than a 'normal' weight individual whose excess weight is mostly fat.

This is especially noticeable with muscular but lean athletes, including rugby players. Jonny Wilkinson was famously 'over-weight' in his prime, as was Brad Pitt when he filmed Fight Club. Mathematician Nick Trefethen at Oxford University thinks that the BMI formula is no longer helpful as he says it makes tall people too fat and short people too thin.

He believes that it's accepted because people like the idea of a simple, scientific equation.

'People put too much trust in it because it's so precise but it doesn't reflect a precise truth about our world, it's an approximation of a complicated reality.'So he's come up with another equation, meaning that those tall people who are 'overweight' by BMI standards, become 'healthy.'

But this doesn't address the fat versus muscle issue. Other experts have suggested using waist measurements, or callipers for body fat testing, rather than BMI would give a more accurate idea of a person's health. Then there are devices, such as specialist scanning or hydrostatic weighing (being submerged in water) which are impractical and expensive.

GP Dr Una Duffy uses the BMI calculation with her patients and defends it: 'On a day-to-day level, there are few situations in which the BMI isn't a good guideline to a person's health. The exceptions are pregnant women, very muscular people and athletes. But generally it works very well and GPs are fans of it.'

She admits though that waist measuring has recently come into play. 'Alongside the BMI, we've started measuring patients' waist as well which show people at risk of strokes and heart attacks. We look at the two figures together to work out a patient's health.'

So, until we get a better alternative, it looks like the BMI is here to stay for now. But don't forget, it's a measure of your height relative to your weight, not how fat or healthy you are. So take it with a pinch of salt.

Liam Nicholls, 34, from St Bee's, Cumbria, is a rugby development officer, and former professional rugby player.

Weight: 96.5kg

Height: 188cm

BMI: 27.22

Verdict: Overweight

'I currently do three weight training sessions a week, two or three cardio sessions, including cycling and running. My job is very active too, as I spend most days running around a rugby field. 'I try to eat a balanced diet with lots of vegetables. I drink plenty of water and take protein supplements regularly to assist with repair. I do have a weakness for cakes and biscuits and occasionally I'll grab a KFC or McDonald's, but I would say the amount of exercise I do more than makes up for this. 'I know that I'm classified as 'overweight' on the BMI scale but I never use it as an indicator of my health. The most important thing to me is how I look and feel in terms of my fitness and physical condition. There are BMI charts in the gym and I've noticed that people are often scared off by them and it can have a de-motivating effect.'

Here's the science bit

Calculate your BMI by dividing your weight in kilogrammes by your height in metres, then divide the answer by your height again.

Below 18.5 = underweight.

18.5 - 24.9 = healthy.

25 - 29.9 = overweight

30 - 39.9 = obese

40 or more = very obese.

What's my BMI?

Kathryn Osbourne, 32, from Carlisle, Cumbria, is a sports therapist (

Dress size: 8

Weight: 59kg

Height: 157cm

BMI: 23.94

Verdict: Normal but close to overweight 'I train 5-6 days a week, a mixture of weights, conditioning work, running and swimming. I also do one body balance class a week for mobility. I eat clean 80-90 per cent of the time and have a treat day on a Friday. I cook everything from scratch and follow a Low GL diet, avoid processed foods, dairy, wheat and gluten. 'A few weeks ago, I saw my doctor and was shocked when she said I was borderline overweight and offered some diet advice! I must be much fitter than most of the people she sees who probably have a "normal" BMI.' Rene Campbell, 36, from Brighton, is a professional body builder (renecampbell. net)

Dress size: 16-18 shoulders, 10-12 waist

Weight: 87.5kg

Height: 5ft 7in

BMI: 30.21

Verdict: Obese

'I eat 4,500 calories a day and train six days a week. Every day, I choose a difference muscle group, like arms, legs or abs, and focus on that. The BMI calculation is completely wrong for me - do I look obese to you? I eat a high protein, low fat diet, exercise six days a week and only have ten per cent body fat which I'll reduce to five per cent for my next competition in June.'

'It's totally outdated. I tell my clients to forget it' 'People put too much trust in BMI because it's so precise - it's only an approximation ' Mathematician Nick Trefethen


Personal trainer Barry Stalker says:

Rugby ace Jonny Wilkinson was 'overweight'

Sceen star Tom Cruise has been seen as 'too heavy' Hollywood idol Brad was far from fighting fit on the BMI scale
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Title Annotation:Features
Publication:The People (London, England)
Date:May 5, 2013
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