Fitness Myths: If you burn more calories training, will you lose more fat?

In this edition of Fitness Myths, we’re going to talk about the quest to burn calories. There appears to be an obsession with burning calories and various ways to burn more in each and every workout.

Advertisements are quick to tout the number of calories you can burn using the latest fitness gadget or while taking the hottest new class. It seems like there’s always something new claiming you can burn 600, no now it’s 800, wait – that's right – you too can burn up to 1,000 calories in a workout! 

So, why the fascination with burning calories? You’ve probably heard the equation “calories in minus calories out” and may think it is that simple. Move more and eat less, right?

Combine that with the “more is better” mentality and it’s easy to arrive at the belief that, if your diet stays constant, then the more calories you burn in a workout the more fat you will lose.  But is this really the case?  

To steal a line from Lee Corso – not so fast my friend. It turns out that while energy balance (calories in minus calories out) is always going to be part of the equation, it doesn’t tell the whole story. And for busy people like you and me, the whole story is the difference between a realistic training regimen that works and one that seems impossible if you still want to be a contributing, happy member of your family and community. 

But let’s not just take a guess at this or deal in personal preference. Let’s look at some real science for our answer, because after all we are dealing with a powerful myth. In 1994, a research study was done comparing 20 weeks of steady-state endurance training (e.g. traditional cardio like running or cycling at a constant pace) with 15 weeks of high-intensity interval training.

The researchers compared the energy costs of the two groups and found that the endurance training group burned more than twice the amount of calories as the interval group.  Yet, despite burning up all this extra energy in the endurance group – the interval group showed a more pronounced reduction in body fatness.

In fact, after adjusting for the energy cost of training (to compare apples to apples or more specifically calories burned to calories burned) the interval training group showed a nine times greater loss in their body fat measurements than the endurance group.  In other words – when comparing calorie to calorie, high-intensity interval training was nine times more effective at burning fat than steady-state endurance training.

A more recent study from 2008 once again compared steady-state aerobic exercise with high-intensity interval training.  This time both groups went through a 15 week program training three times a week.  The aerobic group performed 40 minutes of steady-state cardio work while the interval group did 20 minutes of alternating sprints and recovery.  Both groups expended approximately the same amount of energy per session.  What was the result?  Despite exercising for only half of the time that the aerobic group did, the interval group lost 11.2% of total fat mass while the aerobic group experienced essentially no fat loss at all!

This is just two of the relevant studies.  There are many more covering even longer time periods but all showing that high-intensity interval training outperforms slow and steady aerobic training when it comes to fat loss.

What’s the take home message here?  Exercise science and real world experience doesn’t support the myth that burning more calories while training is the end all be all when it comes to fat loss.  How you burn those calories matters and yet again, quality beats quantity.  So if you seek a lean, toned physique that you can be proud of at the pool, make sure you train hard and don’t waste your time just chasing a number.

Have you heard some fitness advice you aren't sure about?  Leave a comment or send me an email and you may see it in the next edition of Fitness Myths.