The once-a-week workout that helps shrink stubborn belly fat

Stubborn belly fat can be incredibly frustrating.

It changes how your clothes fit. It can make you feel self-conscious. And unlike fat that sits just beneath the skin, the deeper fat that accumulates around your abdominal organs — known as visceral fat — is linked to some serious health consequences.

Excess fat around the middle has been associated with a higher risk of heart disease, fatty liver disease, diabetes, cognitive decline and some cancers.

So, yes, shrinking your waistline can be about looking better.

But it can also be about protecting your health.

The problem? One of the most effective forms of exercise for reducing body fat — high-intensity interval training, or HIIT — is often recommended several days a week.

And for people already juggling jobs, family and everything else life throws at them, that can be enough to make exercise feel impossible before they even begin.

Now researchers have some encouraging news:

Packing your weekly HIIT into just one day may still help you lose body fat and inches from your waist.

One workout day still made a difference

Researchers at the University of Hong Kong recruited 315 inactive adults who were overweight and carried excess weight around their middle. Their average age was 48 and 65% were women.

Participants were divided into three groups.

One group performed HIIT once a week. Another did HIIT three days a week. A third group received health education but did not participate in the HIIT program.

Importantly, both exercise groups did the same total amount of exercise: 75 minutes of HIIT each week for 16 weeks.

The difference was simply how they divided it up.

People in the three-day group spread their exercise across the week, while those in the once-weekly group completed their training during one weekly visit.

After 16 weeks, both groups had lost body fat and reduced their waist circumference.

The once-weekly group trimmed about 2.8 centimeters — a little over an inch — from their waist. The three-times-weekly group lost about 2.6 centimeters.

Both groups also reduced their percentage of body fat and improved their cardiovascular fitness.

There was no statistically significant difference between the two exercise schedules for total fat loss, body fat percentage or waist circumference.

That doesn’t necessarily mean exercising once a week is identical to exercising three times a week. The researchers note that the trial wasn’t specifically designed to prove the two schedules were equivalent, and the three-day group numerically lost somewhat more total fat.

But it does suggest something important:

If exercising several days a week feels unrealistic, one well-planned workout day may still produce meaningful results.

This wasn’t an easy 75-minute workout

There’s an important detail you should know before deciding that once-a-week HIIT sounds simple.

The participants didn’t exercise at full intensity for 75 minutes straight.

Those in the once-weekly group performed three separate 25-minute HIIT bouts, with 15- to 30-minute breaks between them.

During each bout, they alternated four minutes of higher-intensity exercise — reaching about 85 to 95% of their peak heart rate — with active recovery periods.

The workouts were supervised, and participants spent the first four weeks gradually working up to the full routine.

So if you’ve been sedentary, have heart or metabolic problems or haven’t exercised vigorously in a long time, this isn’t a workout to jump into cold.

But the larger message is encouraging: Consistency may matter more than squeezing exercise into an ideal schedule you can’t maintain.

Why losing inches around your middle matters

The researchers did not directly measure visceral fat in this study. They measured total body fat and waist circumference.

Still, waist size is an important marker of central obesity, and carrying excess fat around your middle is associated with some of the health problems we most want to avoid as we age.

For example, abdominal fat has been linked to reduced brain neuroplasticity, which affects the brain’s ability to adapt and recover.

It can also increase the risk of heart failure and release inflammatory compounds that may create conditions that support cancer growth.

That gives you plenty of reasons to take a shrinking waistline seriously — even if the number on the bathroom scale doesn’t change dramatically.

Diet can target visceral fat, too

Exercise gives you one powerful way to tackle abdominal fat.

Food gives you another.

In an earlier study, researchers found that people following a green Mediterranean diet reduced their visceral fat by about 14% over 18 months.

That was twice the 7% reduction seen with a traditional Mediterranean diet.

The green Mediterranean approach emphasizes vegetables, fruits, whole grains, nuts and other polyphenol-rich plant foods while limiting red and processed meats.

You can learn more about the green Mediterranean diet here.

Put the two findings together, and there’s an encouraging takeaway.

You don’t need a perfect exercise schedule or an extreme diet to start changing what’s happening around your middle.

A healthy eating pattern combined with exercise you can realistically stick with can make a difference.

And if three workout days a week have always felt impossible?

One well-planned day may be a much better place to start than waiting for a schedule that never comes.

Sources:

Once and thrice weekly interval training in adults with central obesity: a randomized controlled trial — Nature Communications

This once-a-week workout may help cut belly fat, study shows — Science Daily

The Green Mediterranean diet reduces twice as much visceral fat as the Mediterranean diet and 10% more than a healthy diet — Eureka Alert

FAQ: Once-Weekly HIIT and Belly Fat