Are you a healthy weight? This simple trick can tell you the answer

With so many fad diets and exercise regimes out there, it can be hard to tell what's true and what's not. 

And those who rely on the BMI index, a new study has found that it isn't everything you thought it was. 

The study has found that more than one-third of those at risk of obesity-related problems are considered healthy, per BMI calcultion. 

Now that's worrying news. 

A superior marker to find out the right weight for you is a waist-to-height ratio test, which accounts for extra belly fat (which is linked to heart disease and diabetes). 

The test is easy and takes all of 30 seconds. 

All you have to do is cut a piece of string to the length of your height, then fold it in half and wrap it around your waist. 

If there's an overlap, your at your ideal range. 

If it's a bit snug then it could be time to trim down.