It’s widely known that a woman’s waist-to-hip ratio is an important indicator of her overall health. Now, a new study published in the journal Scientific Reports has shed light on the importance of a man’s waist-to-height ratio, also known as his “waist-to-stature” ratio (WSR), to his overall health and longevity.

Measuring your waist-to-stature is done by dividing your waist circumference by your height. So, a man that is 6 feet tall (72 inches) and has a 30-inch waistline would have a waist-to-height ratio of 0.41, which is roughly the same as the average college swimmer. If you’re under 40, your waist-to-height ratio should not be higher than 0.5. If you’re over 50, a WSR that puts you at critical risk is considered to start at 0.6.

Quick calculations for a 6' tall man:
Under 40, max waist size of 36"
50+, waist under 44"
40-50, although they didn't give a recommendation, guess it's somewhere around a max of 40"

These should be achievable for 99% of Americans.