If you feel the food industry’s helpful labelling system is more like a regular bombardment of kilojoules, percentages of recommended daily allowances and puzzling traffic light systems, you’re not alone.
Most of us understand the advice and can get our heads round the theory, but things become hazy when it comes to amending kilojoule intake. Are you eating enough to sustain your running or are you overestimating the amount of kilojoules that your workout uses up?
USE IT UP, SHARE IT OUT
The average daily allowance for a woman is 8,700 kilojoules. This is based on the average woman’s activity levels. However, none of us are average. We’re all on different training programmes and daily routines, so it would be more accurate to say that most women need between 7,531 and 9,205 kilojoules. It also makes sense to spend some time personalising your kilojoule usage, taking different factors into account. Consider the physical demands of your job and other daily activities, then factor in your sports training.
Next, measure these against your age, weight and body temperature. It’s helpful to keep a record of perceived hormonal changes, taking into account the time of the month, for example. We’re not suggesting that you become a lab rat to work out your calorie usage and consumption to the finest detail, but weighing up all these variables helps you to apply some realism to the figures set out by the Australian Department of Health.
On days when you aren’t training, you need to consume fewer kilojoules, perhaps between 7,531 to 8,368, whereas on training days you can increase your intake to 8,368 or 9,205 kilojoules. If you are training for a marathon you might need a bit more to allow for the extra weekly mileage.
On average, running burns between 335 to 460 kilojoules per 10 minutes, depending on your speed, your weight and the terrain. I prefer to underestimate my kilojoule usage, which helps me to prevent eating all the kilojoules that I’ve burned. Up to this point knowing how many kilojoules you require is easy. To put this into practice you need to know a little bit more about the kilojoule content of food. Most people underestimate this while overestimating their kilojoule usage.
The 837 kilojoules that you eat as an extra allowance on training days equate to quite a modest snack: say half a bagel or half a bowl of cereal per day. In most cases a pre-run banana or peanut butter sandwich will provide those kilojoules.
If you are running to drop weight, you need to reduce your kilojoule intake to ensure that the kilojoules you use over a week and the reduction in your intake adds up to at least 14,644. For this you would need to run for 30 minutes daily as well as lower your kilojoule intake by 1255 kilojoules every day to help you to lose one pound of fat per week. It’s not wise to try to reduce kilojoules any more dramatically than this – reducing your kilojoule intake to less than 5,021 could put your body into starvation mode, which will ultimately prevent weight loss because the little food that you eat is stored as body fat.
THE KILOJOULES YOU FORGET TO REMEMBER
Kilojoules come in the healthiest of disguises, so it’s worth knowing about the ones that can bump up your daily intake by stealth. A ‘healthy’ 250ml glass of orange juice accounts for 460 kilojoules. Just 25g of granola can contain 510 kilojoules. Using two tablespoons of olive oil in your virtuous pasta sauce bumps it up by a whopping 1004 kilojoules. There’s nothing healthy about a spoonful of sugar, but if you take one in your tea, and drink six cups a day, you’ll consume an extra 377 kilojoules a day. Swallowing this sugar-laden hot beverage at this rate you would have consumed 137,444 kilojoules by the end of a year. That means that it’s possible to gain 9.4lbs of fat per annum if your tea consumption is over and above your daily calorie allowance. Over ten years your cup that cheers will have you in tears – because you will have gained six and a half stones in fat. Scary!
- Avoid the sugary foods that cause blood glucose levels to surge; the body converts excess sugar into fat.
- Eat low sugar, high fibre food that helps burn fat. Nuts, berries and fresh vegetables can all perform this function.
- Cut out unnecessary calories and fat from processed foods, such as mayonnaise, tomato ketchup and sweet chilli sauce.
- Ready-made sauces are often packed with sugar and preservatives, so create a healthy sauce for pasta or meat: a five-calorie stock cube and your choice of chopped onions, garlic or other vegetables will do the trick.
- Eliminate sugary, fizzy drinks from your diet.
Words by Anne-Marie Lategan