In other words, those with a defined waist and shapely derriere like the ‘Titanic’ star are better off than those with a small bottom who are plumper around the middle.
Former government adviser Margaret Ashwell worked with a nutritionist from Oxford Brookes University to review data from dozens of studies on the best method of judging someone’s health from their vital statistics.
And their conclusion could mean the end of the body mass index, or BMI – a mathematical formula linking weight to height which has been in widespread use since the early 1970s.
To calculate your BMI, you measure your waist around its narrowest point and divide the result by your height.
A result of between 0.4 and 0.5 is considered healthy, while below 0.4 is classed as underweight and above 0.6 is dangerously overweight.
However, this formula fails to distinguish between fat and muscle, meaning some athletes are classed as obese.
An alternative measure of health is waist circumference, which is considered important because fat that gathers around the stomach is known to be particularly harmful.
Not only does it produce more dangerous chemicals, but it is also closer to the body’s vital organs than flab on the bottom, hips and thighs.
But this method is flawed too, as it doesn’t take into account differing heights. So the solution, says Ashwell, who runs independent consultancy Ashwell Associates, is to look at waist measurement in comparison to height.
Her analysis of 31 studies involving 300,000 men and women from around the world showed doing this to be a better predictor of health than either BMI or waist circumference.
As a rule of thumb, we should aim to keep our waist circumference measurement to under half that of our height.
So, a woman who is 5ft 4in should try to keep her waist below 32in and a man who is 5ft 10in shouldn’t let his waistband exceed 35in.
Any bigger than this and their shape starts to turn from pear-like to apple-like.
Using waist to height as a measure should pick up potential illnesses quicker than BMI and is also suitable for all ages and all ethnicities.
“Keeping your waist circumference to less than half of your height could help increase life expectancy for every person in the world,” the Daily Mail quoted Ashwell as telling the European Congress on Obesity in Lyon.
“You can measure it in centimetres, inches, miles, anything you want. It’s super-simple,” she added.
Pear-shaped celebrities, who are wider below the waist, include actress Kate Winslet and singers Jennifer Lopez and Beyonce.
Among the apples, with less-defined waists, are singer Adele, model Elizabeth Hurley and actress Catherine Zeta-Jones. Ashwell’s system of measuring has another advantage.