### Okay, so you can’t really fit into your high school jeans anymore. But how can you tell if those extra pounds are putting your health at risk?

But, as we reported in the past, BMI isn’t always accurate—in fact, it classifies The Rock as obese.

So researchers from the University of Leeds in the U.K. decided to test a variety of measures—BMI, waist circumference, waist-to-hip-ratio, waist-to-height ratio, and waist-to-height square rooted—to see which was most accurate at identifying obesity in 81 people.

Then, they compared the calculations to results from whole-body DXA scans, which gives whole-body fat percentage and visceral fat mass. (This is the preferred method for testing body composition, but it’s expensive and not readily available, so it’s not a good choice for the average guy.)

They found that waist-to-height ratio was the best predictor of body fat percentage and visceral fat mass. (Anything above 25 percent fat mass was considered obese for men.)

Waist-to-height ratio is calculated by dividing your waist size by your height. The cutoff for men was 0.54—anything above that was considered obese.

Finding an accurate way to gauge obesity is important because BMI isn’t a great way to estimate body fat.

In fact, only 1 in 6 men were obese according to the BMI criterion, whereas nearly half were according to the whole-body fat percentage thresholds.

What’s more, waist-to-height also gives a better indication of abdominal and visceral fat, both of which are more strongly linked to conditions like heart disease, insulin resistance, or other metabolic issues.

So grab a tape measure and pull out your calculator to gauge your risk: Simply divide your waist size in inches by your height in inches.

You want your number to be below 0.54. So a guy who is 5’10” with a waist size of 37 inches would have a ratio of 0.53, making him fall in the non-obese category.

Want to shed fat fast? Try The 21-Day Metashred from Men’s Health—you’ll annihilate calories in nine different, 30-minute home workouts.