Viewers on This Morning have been shown the test to measure their waistlines - and the sizes that are linked to heart disease.
Doctor Chris Steele told presenters Holly Willoughby and Phillip Schofield about the simple test on the ITV show.
He explained that there is a maximum waistline people should have, and any larger than that and people are at risking of heart disease.
The condition is on the rise and the reasons for an increased risk in heart disease was 'not rocket science', he said.
Having a sedentary lifestyle and poor diet are huge contributing factors, along with unnecessary stress, reports Liverpool Echo.
But he urged viewers to check their waist size as this can be an indicator of an increased risk.
Dr Chris said: "A man's waist should be no more than 38 inches, and 32 inches for a woman."
Measuring your waist is a good way to check you're not carrying too much fat around your stomach, which can raise your risk of heart disease, type 2 diabetes and stroke.
And this is something the NHS agrees on, although they say no more than 37 inches (94cm) for a man and 31.5 inches (80cm) for a women.
They say you are at very high risk if you are a man and your waist is over 40 inches (102cm) or if you are a woman and your waist is over 34 inches (80cm).
The NHS said: "You can have a healthy BMI and still have excess tummy fat – meaning you're still at risk of developing these diseases."
How to measure your waist:
- find the bottom of your ribs and the top of your hips
- wrap a tape measure around your waist, midway between these points
- breathe out naturally before taking the measurement
