It's Not Easy to Lose Fat ... Do the Math and See Why!

I've been meaning to post this one for a little while, just never got around to it. But to mark the final week of the Biggest Loser contestants' residence in the White House, I thought now might be a good time to open some eyes.

I love watching The Biggest Loser. But one thing a lot of people just don't comprehend is how difficult it is to lose weight. So I thought a little math lesson in weight loss might help some of you to see what sort of effort is required to lose weight.

The generally recommended rate of weight loss amongst nutritionists and fitness professionals is between 0.5 to 1kg per week. This is considered to be both safe and maintainable in the long term. Does that rate sound too slow for you? Well then keep reading.

When I refer to "weight loss" I am specifically talking about FAT LOSS. Most of us are aware that if you drink 1L of water then you will weigh 1kg heavier... but losing water weight is not what ultimately will change your body shape.

For the purposes of this math lessons, let's be conversative and aim for a weekly loss of 0.5kg (500g) of fat. To lose weight, you essentially have to spend more energy than what you eat. So, how much energy is in 500g of fat?

1g fat = 9 calories
Therefore, 500g fat = 500 x 9 = 4500 calories

So in one week, you need to use 4500 calories more than you eat! Bet you didn't realise just how massive that number would be!

Let's break that down into a more manageable figure:

4500 calories per week = 4500 calories in 7 days.
Therefore 1 day = 4500/7 = 643 calories per day.

If you decide to try to lose weight through diet alone, I can guarantee that not only will you find this difficult, you will be hungry all the time. You will probably also be likely to not just lose fat weight, but muscle weight too. This in itself could be another blog post, but for now, just take my word for it that you do not want to lose muscle weight. Trust me.

640 calories is not burnt in a mere 30min brisk walk. Nowhere close!

30min moderate walk (6km/h) = 130 calories
30min brisk walk/light jog (8km/h) = 260 calories
30min run (10km/h) = 340 calories

This morning, I taught an aerobics class which was a combination of Step and Hilo. My heart rate monitor informed me that I burned 510 calories in 47mins (the class was actually 90mins long, but I kept forgetting to turn the computer monitor on at the start of my classes, so I'm generally only recording half of my classes... ugh!).

This might sound great to you - do a 1hr aerobics class, and Bob's Your Uncle, you've clocked in your daily 643 calorie burn time. What most people forget to factor into the equation is how hard do they work during the class? Some of my participants certainly do work hard, but others do not. And let me tell you, when I teach an aerobics class, I probably work harder than when I simply participate in a class. Sure, I sweat when I participate, but when I teach, I don't just sweat... it actually drips off me! According to what I've read online, on average you can burn about 300 calories in a 1hr Step class... maybe more in a Hilo class (if you work hard enough in the Hilo class that your average heart rate is higher than in a Step class).

The purpose of this post is not to paint an impossible picture and make you feel like you can't ever lose the weight. It's to help you appreciate that losing weight IS hard work. There are no shortcuts (apart from liposuction I suppose, and even that requires lots of $$ and pain!). If there were shortcuts, then our nation would not be going through an Obesity Epidemic.

And as for those diets that promise you will lose 7kg in 14 days ... they work short term but won't sustain you for life. Plus, that 7kg is not predominantly fat.

Next time: Tips for a Successful Workout Program