Stand by... the ideal fat loss program is... lie on the couch and watch TV.
And the best fat burner - with a 70% contribution - is plain simple ol' rest.
According to Chris Tzar, an exercise physiologist and director of the Lifestyle Clinic in the Faculty of Medicine at the university, the greatest contribution from fat stores as a percentage occurs during rest. That means approximately 70% of the body's fuel is derived from fat sources for the average individual at rest.
"If we define fat-burning activities in percentage terms, then theoretically, the ideal fat loss program would be to lie on the couch and watch TV," he said.
However, study author Professor Steve Boutcher pointed out that although the study data was much more impressive than that comment might suggest, it did highlight the importance of tailoring exercise to an individual to accommodate their specific goals and health needs.
Fartlek the Key To Fat Loss
His 15-week study involved 45 overweight women. The key finding was that 20 minutes of exercise of variable intensities was more effective than 40 minutes of steady-state exercise in achieving body fat loss and aerobic fitness.
The winning formula was based on a form of training known as "fartlek", a Swedish word meaning "speed play". It's a term I came across many years ago when Paarvo Nurmi and other great Scandinavian runners were dominating world middle distance running.
Their idea was to run through the forest, "playing" with their speed. They might jog for miles, then suddenly sprint uphill, lope down the other side, or run an unmeasured ridge at 75% effort, just as the mood took them. Or the other way around. Their results were outstanding.
When you think about it, the process makes sense. Any athlete wanting to break up a pack knows that "surging" will soon drop off the weaker competitors. And surging - essentially, putting in a short fast burst - demands extra energy that the tired athletes simply do not have.
The university's variable-intensity sessions comprised eight seconds of sprinting on a stationery bike, alternating with 12 seconds of light intensity. These 20 second cycles were repeated 60 times for a total of 20 minutes.
The other group exercised at a constant intensity equivalent to 60 percent of their maximal effort for 40 minutes.
Outsanding Health Pointers
In an article in The Australian newspaper in January 2007, Tzar noted another intriguing benefit discovered in the fartlek group - they improved their fasting insulin by 31 percent, compared with 8 percent in the constant group.
It's preliminary data, but he suggested that the findings might have implications for insulin-resistance disorders such as type 2 diabetes and polycystic ovarian syndrome.
One other important point he made in the article is that the health benefits of exercise are just as high for obese people as they are for lean types.
"While many people may focus on the cosmetic benefits of exercise, the major health benefits - which are of greater importance - are often invisible," he said.
"... the appropriate exercise program for any individual needs to consider their own unique circumstances."
So, fast body fat loss tips or overall health... you might like to dig a little deeper into the fartlek philosophy.