Calories: Who’s counting?
We hear so much in the media about calories. How many calories are in this chocolate bar? How many calories do I burn doing a push up? But what really is a calorie?
Calories are a way of keeping track of our body’s energy budget. A healthy balance is when we put in as much energy as we use. If we consistently put more energy into our body than we burn, the excess will gradually be stored as fat and we’ll gain weight. If we consistently take in less energy than our body requires this will lead to weight loss.
The technical term for one calorie that we measure in food is defined as the amount of energy it would take to raise the temperature of 1kg of water by 1 degree celsius.
Everything we consume has a calorie count, a measure of how much energy it stores in its chemical bonds. The energy is released during digestion and stored in other molecules for when the body needs it. For example, one green apple has approximately 95 calories, whereas a Big Mac has 550 calories.
Calories are used in three ways – 10% digestion, 20% physical activity and 70% to our basic body functions of our organs & tissues. The basic body functions are formally known as our BMR (Basal Metabolic Rate) which means how many calories our body needs to survive without eating or moving around. Add in some exercise and digestion and then you’ll have your calculation to how many calories per day you need to maintain your weight. Everybody is different in how they burn calories on a day to day basis. For example, a tradie is much more physically active compared to an office worker so their daily calorie intake must be different.
Some foods offer nutrients like protein & vitamins while others offer far less nutritional value, so eating too much of those foods may lead to weight gain or malnutrition. Fibrous foods take more energy to digest, for example 100g celery will leave you with less energy after.
Here is an estimate of how many calories we burn during exercise.
A medium banana that offers you 105 calories will give you less than 30 minutes of light activity. So, if you’re planning your nutrition for a sporting event be sure to allow enough calories for the time you’ll be competing for, or you may risk a depletion in energy, resulting in poor performance.