Waist measurements are increasing, even for those with normal a BMI, meaning we need to rethink the ways we monitor our overall wellbeing.

Read on and you’ll discover:

• Why “normal weight obesity” is becoming more prevalent

• The importance of weight measurement in predicting health issues such as heart disease, high blood pressure and metabolic syndrome

• A simple formula for accurately measuring your waistline

• The workout that’s scientifically shown to cut inches from waistlines.

If you’ve ever tried on vintage garments from 1970s or earlier you’ll have noticed that people were smaller back then. Both men and women had, on average, narrower shoulders and waists. Since then, garment measurements have crept upwards; a vintage size 12 is more like a modern size six.

The fact that people have become larger over time is partly down to better overall nutrition. We have more nutrients in our diets now, and over time this has meant we’ve grown taller and stronger. But somewhere in the past 50 years – at least in Western countries – we tipped into over-nutrition. We have more calories, of lesser quality, than we need. And that’s meant we’ve become not only bigger, but fatter.

It’s easy to see this in our waist measurements. Scientists have known for some time that a person’s waist measurement is an indicator of their health risk. It was thought this was related to obesity – a bigger waist means it’s more likely someone is obese, and that usually comes with other health problems.

Waist measurements are going up, and not just because we’re getting fatter overall.

More recently, however, researchers have found waist measurement predicts more than just obesity. Whether a person is obese or not, having a larger waist makes them more likely to be at risk for certain diseases, including metabolic syndrome, high blood pressure, type 2 diabetes and heart disease. It’s a condition known as normal weight obesity or central obesity.

Now an international group of experts is calling for waist measurement to be included in routine medical checks, and for a range of waist measurement thresholds to be set for people of all weights, allowing doctors to make better risk projections for their patients.

In a recently-published report, the International Atherosclerosis Society (IAS) and International Chair on Cardiometabolic Risk (ICCR) Working Group on Visceral Obesity say this is vital because our waists are getting bigger, beyond what might be expected from looking at body mass index (BMI) alone.

One Canadian study found that for any given BMI, Canadians had a larger waist circumference in 2007 compared with 1981. In other words, waist measurements are going up, and not just because we’re getting fatter overall.

That’s bad news because in any BMI category – even within so-called “healthy weight” parameters – adults with higher waist circumferences are at increased health risk compared with those with smaller waists.

Up until now, a one-size-fits-all measurement – over 102 cm for men, over 88 cm for women – was an indication of abdominal obesity. Anything under that, no matter your BMI, was okay. Now we know that’s not necessarily the case.

The IAS has suggested new measurements based on different BMI measures. Using this more refined approach provides a fuller picture of health; repeating measurements over time will help predict potential risk. (Note: different ethnicities have slightly different thresholds.)

If you find your waist is above the recommended measurement, the IAS says “numerous epidemiological studies and RCTs have now demonstrated that reductions in waist circumference can be achieved by routine, moderate-intensity exercise and/or diet changes.”

Advice on how to achieve that differs depending on which part of the internet you’re reading. Contrary to persistent belief, we can’t target body fat with specific exercises. But there’s good research to show that high-intensity interval training (HIIT) can reduce visceral fat better than standard workouts. Strength training to increase muscle mass is also important. When we have more muscle, we burn fat more efficiently, even when we’re not exercising.

As far as nutrition goes, experts say there are no magic foods (again, despite what Insta says). But cutting out ultra-processed foods will go a long way towards cutting overall body fat and by extension, the dangerous stuff that lurks around the organs. That means ditching the sugary foods and drinks, refined white carbohydrates, fatty and salty snacks. Replace them with whole, fresh foods (mostly plants) and you’ll be on the right track.

How to measure your waist

First calculate your BMI using the formula: weight divided by height in meters squared (kg/m2) – there are simple online calculators such as this to make it easy.

Now measure your waist and check it against the ISA guidelines to see how you compare. Another simple rule of thumb is that if your waist measurement is less than half your height you’re probably doing OK.

Be honest! We’re often terrible at measuring our waist – sucking in our gut, under- or over-estimating. There are good guidelines online for this too. It’s worth doing several measurements – it’s not unusual to find variation, so try taking an average.

How to use exercise to reduce your waistline

If you’re looking to carve inches from your waistline, research shows LES MILLS GRIT™ is one of the best ways to do it. Read all about the tummy-trimming benefits of this specific form of HIIT training here.

A lean waistline isn’t the only way LES MILLS GRIT benefits your health. In the video below you can see what happened when the Les Mills Lab teamed up with Dr. Jinger Gottschall to explore how LES MILLS GRIT can impact the fitness and body composition of fit and active adults.

Find a LES MILLS GRIT workout near you or get 24/7 unlimited access to online workouts with LES MILLS™ On Demand.

Find a workout work out on demand

Niki Bezzant is a New Zealand-based food writer, editor and commentator. She is the founding editor (now editor-at-large) of Healthy Food Guide magazine, and is currently president of Food Writers New Zealand and a proud ambassador for the Garden to Table program which helps children learn how to grow, cook and share food. She is a member of the Council of Directors for the True Health Initiative, a global coalition of health professionals dedicated to sharing a science-based message of what we know for sure about lifestyle and health.