The Myth: You Can Spot Reduce Fat

MYTH: YOU CAN SPOT-REDUCE FAT

Many runners spend too much of their gym time doing a bazillion crunches in pursuit of rock-solid abs or banging out hundreds of reps on the inner and outer thigh machines to melt away stubborn fat pockets.

But the only way you can spot reduce is with liposuction.

“When you exercise, your body taps into energy stores from everywhere, not just one place,” says exercise physiologist Pete McCall, a trainer certified by the American Council on Exercise. McCall adds that by overexercising one area of your body, you raise the risk of suffering an injury.

“It’s good to have a strong core, but too many crunches can overtighten abdominals and lead to back problems.” McCall suggests targeting a particular body part no more than three times a week, and focusing on a balanced full-body programme. “This will help create a calorie deficit, and ultimately that’s the only thing that’s going to slim those thighs and trim your belly.”

Many of us think running burns 100 calories (260 kilojoules) per kilometre – but this is only true if you weigh 63 kg. To calculate your kilojoule burn per kilometre, multiply your weight in kilos by 4.13. A 80-kg runner burns 330 kilojoules per km; a 55-kg runner burns just 227. And if you run faster, you don’t burn more calories per kilometre – but you do burn more per minute.

The number this formula yields is your “gross” kilojoule burn. But it can be deceptive: Even if you didn’t run at all, you’d still burn calories. A 68kg person burns about 285 kilojoules an hour doing nothing.

This is your basal metabolic rate, or BMR.

When you subtract your BMR from your gross burn, you get your “net” burn. If you’re trying to maximize your burning efficiency, compare the net burn per minute of various activities.

Walking burns far fewer calories per minute than running because it doesn’t require as much effort. But cyclists can go so fast that air resistance becomes a factor. Thus, cycling 40 kmph burns much more than double the kilojoules of cycling 20kph.

Below is the gross kilojoule burn per kilometre and net kilojoule burn per minute of various activities. As noted, it’s the second number that gives the truest picture of an activity’s kilojoule-burning efficiency—that is, how to get the max from the minimum time investment.

Running 8km p/h (12:00 pace)
Gross Kilojoules Burned Per KM: 281
Net Kilojoules Burned Per Min: 33

Running 16km p/h (6:00 pace)
Gross Kilojoules Burned Per KM: 281
Net Kilojoules Burned Per Min: 71

Walking 5km p/h (20:00 pace)
Gross Kilojoules Burned Per KM: 221
Net Kilojoules Burned Per Min: 13

Cycling 25km p/h
Gross Kilojoules Burned Per KM: 48
Net Kilojoules Burned Per Min: 16

Cycling 37km p/h
Gross Kilojoules Burned Per KM: 94
Net Kilojoules Burned Per Min: 56

Swimming 4.12km p/h (1.46 mins/100)
Gross Kilojoules Burned Per KM: 857
Net Kilojoules Burned Per Min: 54

-Amby Burfoot

More Weight-Loss Myths Exposed

The Myth: Running on empty is a smart way to burn extra fat
The Myth: Exercise in the fat-burning zone
The Myth: Weight-lifting will only bulk you up
The Myth: Low fat foods are a healthy choice
The Myth: Eating at night causes weight gain