Maintaining a healthy weight has a lot to do with balancing the energy we consume through eating food with the energy we expend through every day living and physical activity.

Did you know that all food, regardless of it’s nutritional value, contains energy?

The energy in food comes in the form of protein, carbohydrate and fat. The body breaks down these macronutrients to access the energy stored in their bonds. Energy is measured in units known as kilojoules (the Australian way) or Calories (the American way). To convert from one unit to another 1 calorie (C) = 4.2 kilojoules (kJ).

Although all food contains energy there are certain foods that we eat which contribute extreme amounts of energy to our bodies without supplying adequate vitamins, minerals and fibre. These foods are sometimes labeled as containing ‘empty calories’ or as having low nutrient density.

The problem with these foods is not that they make you ‘fat’ all on their own, it’s that they tend to contribute lots of energy to our daily intake and if we aren’t doing sufficient physical activity, the excess energy we consume is stored as fat.

I’d like to a list a number of commonly enjoyed foods and illustrate how much energy they contain by the type and amount of exercise you’d need to do to burn it off. The foods I’ve listed are known as empty calories or have poor nutrient density. This means they contain plenty of energy but small amounts of vitamins, minerals and fibre and contribute very little to our health if at all.

The following values are based on a 60kg person (a larger person burns more energy and smaller person burns less):

  • 1 slice of strawberry cheesecake = 960kJ (230C) and 30 minutes on the cross-trainer set to hill-training.
  • Pasta Carbonara ordered from a cafe = 5851kJ (1401C) and 3 hours of high intensity exercise (running, hard cycling or cross-training).
  • Cinnamon doughnut = 760kJ (182C) and 20 minutes on the rowing machine.
  • 600ml bottle of Coke = 1080kJ (258C) and a 5km jog.
  • Mars Bar = 1050kJ (251C) and a leisurely bike ride for just over an hour
  • Small pack of plain chips (50g) = 1064kJ (255C) and a 1 hour dance class with very little rest periods.
  • Large french fries = 1900kJ (455C) and 1 hour and 15 minutes of jogging/walking intervals
  • Big Mac = 2060kJ (493C) and climbing stairs continuously for a whole hour.
  • KFC Snack box = 2087kJ (499C) and pushing a toddler in stroller for 31/2 hours.
  • 25g (2-3 pieces) chocolate = 555kJ (133C) and 450 pushups in a row.
  • 2 Tim Tams = 812kJ (194C) and 30 minutes of doubles tennis.
  • Cafe BLT & chips = 3540kJ (848C) and 2 hours of mountain climbing (no down hills!)
  • Waffles with icecream and maple syrup = 1322kJ (316C) or cleaning gutters on your house for an hour.

Like I said earlier, individual foods don’t make you fat. It’s your diet as a whole that is important in determining whether there is too much energy being consumed overall. The above list also clearly illustrates that without regular moderate intensity exercise of at least 40 – 60 minutes duration we are not likely to be burning sufficient energy to maintain our weight either.

If you are struggling with losing weight or learning how to eat better or maintain your weight, my ebook, The Healthy Eating Weight Loss Plan will teach you balanced, healthy eating, good portion control and the best food choices for good health and weight loss.

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