Can You Really Lose More By
By Christian Finn
|Just the other day, I came across a story about
another “revolution in weight loss,” with scientists
claiming to have devised a workout that burns three times
more fat than regular workouts lasting twice as long.
According to the story, the researchers found their specific
brand of interval training triggers a metabolic response
that allows more fat to be burned under the skin and within
Can you really lose weight three times faster with only half
Here, as Kent Brockman would put it, is my two cents…
First, let’s take a closer look at what happened in the
Researchers at the University of New South Wales and the
Garvan Institute studied a group of overweight women,
putting them through a 20 minute cycling regime in which
they sprinted on a stationary bike for 8 seconds followed by
12 seconds of cycling lightly . The women performed the
workout three times a week for 15 weeks.
“They lost three times more weight than other women who
exercised at a continuous, regular pace for 40 minutes,”
says University of New South Wales Associate and study
co-author Professor Steve Boutcher. The scientists believe
the regime would also be applicable to swimming, walking,
running and rowing.
Other types of interval training using longer work and rest
periods, says Professor Boutcher, are not as effective for
overweight people. As far as I can tell, the work-rest ratio
(8-second sprint, 12-second recovery) is based on a previous
study by the same researchers showing that short work and
rest ratios burn more calories than longer (24-second
sprint, 36-second recovery) intervals.
||Boutcher thinks the
current government recommendations for exercise are
“Walking for 60 minutes, seven times a week does not result in much fat
loss, usually 1.15 kilograms over 15 weeks,” he says.
“For a lot of overweight people this is going to be a
So, is this a revolution in weight loss?
Maybe… if you’ve had your head in the sand for the last 10
Using interval training to lose fat
is certainly not a revolutionary idea. It forms the core of
the cardiovascular workouts featured in the Fight Fat and
Win (FFW) programs. And there are plenty of other people who
have been writing about it — and using it — for a number of
However, even though interval training is both a highly
effective and time-efficient way to train, saying that it’ll
help you lose weight “three times faster” than regular
cardio does (in my opinion, anyway) paint a rather overly
optimistic picture about what to expect.
I’ll explain why in a moment.
Yes, I know that interval training is often said to be “nine
times” more effective than steady-state aerobic exercise.
However, if you’ve actually read the study on which this
claim is based (Interval Training and Fat Loss: The Untold
Story), you’ll know that neither group in the study lost a
significant amount of weight. The aerobic exercise group
lost one pound, while the interval-training group lost an
average of just 100 grams. And that was after 15-20 weeks of
With all the fuss about interval training and fat loss,
you’d think there are dozens of studies to show that it
consistently leads to greater fat loss than steady-state
cardio. But there aren’t.
It’s true that interval training is a great way to increase
calorie expenditure in the hours after exercise. It’s also
been shown to boost the activity of various fat-burning
enzymes. However, most studies of interval-style workouts
have looked at changes in performance and fitness, rather
than weight loss.
Studies to track changes in body composition are few and far
between, which is one of the reasons this Australian study
caught my eye.
However, when I looked at the research in detail (and the
paper has yet to reach the pages of a peer-reviewed journal,
so I only had access to a short summary of the study), the
results weren’t quite as exciting as they first appeared.
At the end of the 15-week study, the interval-training group
had lost, on average, 2.5 kilograms (5.5 pounds) of fat. The
steady-state group actually gained 0.5 kilograms (1.1
So, the actual amount of fat lost in the interval training
group wasn’t all that great — 5.5 pounds over 15 weeks,
which works out at just 0.37 pounds of fat loss per week.
This figure doesn’t really grab your attention like “three
times greater weight loss.”
In fact, I can’t actually figure out how the researchers
arrived at a figure of “three times greater weight loss,” as
the interval-training group lost weight while the
steady-state group gained it.
What about diet? How did that affect the results?
Although the women’s calorie intake was monitored using a
food diary, self-reporting is a notoriously inaccurate way
to estimate calorie intake. Some studies show that people
underestimate their calorie intake by up to 50% . In
other words, someone who says they are eating 1000 calories
per day may really be eating 2000 calories.
So, changes in calorie intake might have been primarily
responsible for any weight loss. Or they might have had
nothing to do with it. We don’t really know for sure.
And we still don’t know how well interval training compares
to more intense steady-state cardio. This study used only
moderate-intensity cardio (60% VO2max). To trigger a
substantial post-exercise calorie burn, you need to work at
around 75% of VO2max, or 85% of your maximum heart rate.
It’s possible that steady-state cardio performed at or above
this threshold would produce very similar results to
With all that said, I still think that interval training is
a great way to lose fat. It’s something I use myself and
recommend to others. In fact, the interval training used in
this Australian study is very similar to the level III
workout in the Fight Fat And Win (FFW) program, which
involves a 25-minute workout sandwiched between 5 minutes of
warming up and 5 minutes of cooling down.
However, interval training alone is not a magic bullet, and
I think most people would be disappointed losing only 5.5
pounds of fat after 15 weeks of exercise. A program that
combines resistance exercise, good nutrition AND interval
training is one that will deliver the best results.
1. Trapp, E.G. & Boutcher, S.H. Fat loss following 15 weeks
of high intensity, intermittent cycle ergometer training.
University of New South Wales, Sydney, Australia
2. Lichtman, S.W., Pisarska, K., Berman, E.R., Pestone, M.,
Dowling, H., Offenbacher, E., Weisel, H., Heshka, S.,
Matthews, D.E., & Heymsfield, S.B. (1992). Discrepancy
between self-reported and actual caloric intake and exercise
in obese subjects. New England Journal of Medicine, 327,
About Christian Finn
Christian Finn holds a masters degree with distinction in exercise science. He has lectured at universities and private training organizations around the United Kingdom on fitness training, weight loss and the effective use of supplements.
If you live in the UK, you may have seen Christian in the BBC TV series Body Hits. Christian was also the fitness expert for the Bravo TV series All About Men.
You can find Christian's articles published in numerous magazines, journals and websites worldwide, including Men's Health, Men's Health Muscle, Fit Pro, CAM magazine, Image, Zest, and Body Life magazine. You also might have seen Christian featured in the July 2004 issue of Muscle & Fitness.
A tireless researcher, Christian has lost count of the number of hours he has spent reviewing the latest scientific research on diet and exercise for the benefit of his readers. Christian’s research on high-intensity intermittent training has been published in the online journal Sport Science (March 2001).
As a certified personal trainer, Christian has spent more than a decade working with people of all shapes and sizes, as well exercising regularly himself for over 15 years.
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