The size of your bottom line is a numbers game
Hands up if you’ve stepped on the scales yet this year? Well, I have, and it’s not pretty.
In 2011, I dropped a whopping 20 kilograms by improving my diet and beginning to exercise. In 2012, I put 8 kilograms back on, by pretty much doing the reverse. I’m not alone: many people who lose weight put it back on as old habits return. And I’m hardly surprised: I remember all the chocolate bars, serves of chips, bottles of wine and nights on the couch that explain my regain.
But, alarmed at the prospect of becoming the next Oprah or Kirstie Alley, I’ve decided it’s time to reverse the slide. And I’m going to do it the only way I know how – with economics. The federal government’s budget bottom line may be blowing out, but I’m determined to get mine under control. Today I weigh 74.7 kilograms. By the federal budget in May, I vow to weigh 65 kilograms. To do this I will need to become the Treasurer of my own body.
Because weight management, like budgets, comes down to one very simple equation: calories in minus calories out.
Consume more energy than your body needs each day and the body does the only thing it can – it stores the excess energy in fat cells.
The good news is that your body needs a certain amount of energy each day just to grow eyelashes, pump your heart, grow skin cells etc.. You’re supposed to eat! How much, though, depends critically on how big your body is - your height and weight - and also your age and sex.
For me, at 1.79 metres and weighing 75 kilos, my body needs 1550 calories a day to perform these essential functions. Just search the internet for “basal metabolic rate calculator” to find out your own daily calorie requirement.
Of course, we also burn calories each day doing incidental exercise, like walking to work, to the toilet and getting meals. But if you’re fairly sedentary, like me, this may only add an extra 200 or 300 calories to your daily calorie needs.
I estimate that, all up, my body needs about 1800 calories a day (1550 plus 250). So, if I consumed 1800 calories a day, I should roughly maintain my weight over time.
The secret to losing weight is to eat less than your body needs, forcing your body to dig into your body fat stores for the fuel it needs.
Now here’s a scientific fact you need to know.
Studies have shown that each kilogram of body fat contains energy stores equivalent to roughly 7500 calories.
Create a calorie deficit of 7500 calories, over whatever time period you like, and you will lose 1 kilogram of fat as the body uses up the energy stored there.
It gets complicated because metabolisms vary, but I suspect it’s a good rough guide and I plan to test the theory.
So, starting yesterday, I am restricting my food and drink intake to 1500 calories a day.
Given that my body needs 1800 calories a day, this means I should open up an immediate daily deficit of 300 calories. Each week that adds up to a deficit of 2100 calories.
My goal of losing 10 kilograms means I need to build, over time, a cumulative calorie deficit of 75,000 calories. At this pace, it would take me 36 weeks to lose 10 kilos.
If counting calories sounds like a lot of hard work, that’s because it is. But with great websites and smartphone apps like calorieking.com.au and myfitnesspal.com.au it’s never been easier.
And once you know how densely calorific some foods are, it’s hard to forget. Did you know there are 181 calories in one slice of pepperoni pizza? That’s 1448 calories for the entire pizza – my entire daily calorie allowance.
A bottle of red wine will set you back 550 calories. A skim cappuccino about 150 calories. And here’s a killer – just one tablespoon of olive oil contains 146 calories.
So, take the time to educate yourself about calories. Read nutrition labels and remember one calorie equals 4.2 kilojoules. Make your calories go further by eating plenty of vegetables and lean meats and avoiding sugary and fatty foods. Another fun fact: white meats, like chicken, pork and white fish, contain one calorie per gram, half the calorie content of red meats and salmon, which contain two calories per gram.
So, step one, consume fewer calories than your body needs.
Step two, turbo charge the equation with exercise. Additional exercise builds the calorie deficit faster by increasing the amount of energy your body needs.
Time is scarce, so it’s important that you exercise effectively. The best tip I have is to buy a heart rate monitor. These monitors reveal when you are exerting yourself and when you’re not trying hard enough. They also tell you how many calories you burn in a session. For me, doing a slow jog burns about 500 calories in 50 minutes. And when I say slow, I mean I occasionally get overtaken by people walking.
So my plan is to boost my calorie deficit by burning an extra 2000 calories a week through exercise. In effect, this means four of my slow jogs a week.
Adding these 2000 exercise calories to my 2100 food calorie deficit should bring my weekly calorie deficit to 4100. At this rate, it will take a little over 18 weeks to build a deficit of 75,000 calories and drop the 10 kilograms.
Being the big dork that I am, this happily coincides with one of the highlights of my calendar – the federal budget, on the second Tuesday every May.
I’ll let you know how I get on.
Jessica Irvine is National Economics Editor. Weight: 74.7 kilograms. Goal weight: 65 kilograms. Weight loss this year: 0.0 kilograms.
Follow her weight loss journey on Twitter: @Jess_Irvine
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