4.2 A Balanced Diet

YOUR ENERGY NEEDS Even when the body is resting it requires energy. You need it to keep warm, keep your heart beating and lungs breathing, and for all cell reactions that take place. Basal metabolic rate (BMR) is the amount of energy you need to stay alive, awake and comfortably warm. For movement, food digestion and exercise, you need more energy. This is called working energy and depends on how active you are. Basal metabolic rate + working energy=Total energy needed Energy is measured in kilojoules (kJ) or in kilocalories (C) 1 kilocalorie = 4.18 kilojoules

Total energy needed in a day Male Female 8 year old 15 year old Adult (office work) Adult (heavy work) Retired 8200 11 500 10 500 14 000 9000 7300 8800 7000

How much energy do foods give? Your body is able to use carbohydrates, fats and then proteins for energy. Compare the energy each gives: 1 gram of carbohydrate 17.1 kJ 1 gram of protein 18.2 kJ 1 gram of fat 38.9 kJ A gram of fat gives over twice as much energy as a gram of protein or carbohydrate. This is why it is very easy to eat much more fat than you need for energy. When this happens you put on weight. Most foods are a combination of the three. Look at labels on food to find out what you’re eating!

THE ENERGY BALANCE An 8 year old boy needs around 8200 kJ a day THE ENERGY BALANCE An 8 year old boy needs around 8200 kJ a day. Suppose he eats enough to give 12, 000. The extra kJ do not get excreted, they get stored as fat. Remember, even excess carbohydrate and protein are converted to fat and stored. It’s important to keep a balance between energy going into your body, and energy expended through exercise. If energy in is more than energy out, you will put on weight. If energy in is the same as energy out, your weight won’t change. If energy in is less than energy out, your body will start using stored body fat for extra energy and you will lose weight.

THE HEALTHY FOOD PYRAMID A Balanced diet: 55% carbohydrates 30% fat 15% protein

Corn Chips (per 50g) Kcal 250 kJ 1045 Powerade (250ml) Kcal 65 kJ 275 Coke can Kcal 151 kJ 627 Pizza slice Kcal 217 kJ 910 Currywurst Kcal 271 kJ 1134 Large Big Mac Meal Kcal 1172 kJ 4894

Pasta (per serve) Kcal 75 kJ 312 Multi grain bread (1 slice) Kcal 80 kJ 334 The Angus Deluxe Burger from McDonalds is over 3000kJ (without fries or drink) That can equal around 60% of your recommended daily intake. Rice (1 cup) Kcal 242 kJ 1012 Cornflakes (per serve) Kcal 101 kJ 423

Black coffee – 10KJ Cafe latte – 260KJ Americano – 300KJ Frappe – 600KJ Mochaccino – 880KJ Cappuccino Kahlua – 800KJ

TASK Using your food diary, identify different foods that are carbohydrates, fats and proteins. Where you can, write down the approximate number of kilojoules for different foods. Also, take note of your recommended daily intake. Suggest some areas for improvement, and some possible healthier alternatives.