Healthy Eating
Energy in food
While there are many factors involved, an increase in body weight always results from an imbalance between energy intake (food) and energy expenditure eg metabolism and physical activity.
Energy is not a nutrient but is released from food components. The energy obtained from food is measured in kilojoules or calories. Fat, carbohydrate and protein provide energy but are found in foods which also supply vitamin and minerals. Alcohol (not essential to the body) contains energy but alcoholic drinks do not generally provide any vitamins and minerals. Protein contains 17 kJ/g, fat contains 37 kJ/g, carbohydrate 16 kJ/g and alcohol contains 29 kJ/g.
As you can see, fat and alcohol supply around twice the kilojoules as the same amount of carbohydrate and protein. When we eat more energy than our body needs, the excess is stored as fat.
The kilojoule content of foods depends on the amount of carbohydrates, fats and proteins present in the food.
The Australian Guide to Healthy Eating and the Australian Dietary Guidelines provide information about healthy eating. These publications can be viewed at: www.health.gov.au/internet/main/publishing.nsf/Content/health-pubhlth-strateg-food-resources.htm#consumers
For more information on the role of various nutrients in the diet check out the following site: Vitamins and Minerals
What are your energy requirements?
The total amount of food needed each day will vary with age, sex, body size, activity levels, and whether or not you are pregnant or breastfeeding. However, as a general guide your kilojoule requirements for the day can be found in the Nutrient Reference Values for Australia and New Zealand including Recommended Dietary Intakes at the following site: http://www.nrv.gov.au/It is recommended that you distribute your energy intake across the various food groups as outlined in the Australian Guide to Healthy Eating.
The recommendations for energy intake have been based on standard weights and heights and predictive estimates are much less accurate for individuals than for groups. Variations in energy expenditure can be quite large, even between apparently similar individuals because of genetic differences and/or the amount of physical effort put in when undertaking certain activitites. Specific advice for individual needs should be sought from a qualified dietitian.
Most foods contain mixtures of all three energy yielding nutrients in different proportions. Carbohydrate is important for providing energy to all body cells. The majority of carbohydrates in the diet should come from foods like wholegrain breads, cereals, rice, pasta, legumes and vegetables.
Carbohydrate is important for providing energy to all body cells. The majority of carbohydrates in the diet should come from foods like breads, cereals, rice, pasta, legumes and vegetables.
Protein is important for the creation, maintenance and renewal of body cells. It is important for the growth and repair of everything from muscles and bones to hair and fingernails. Protein is also vital for producing antibodies that help fight infection, creating enzymes that help us to digest food and hormones to keep the body functioning effectively. The best sources of protein in the diet are cereals (wheat, oats, rice and bread), milk, yoghurt, cheese, meat, poultry, fish, eggs and legumes.
Fat is a rich source of energy and is important for carrying fat soluble vitamins A, D, E and K and antioxidants. Fats also supply essential fatty acids for healthy skin and have a role in regulating body functions.
However, eating too much fat (particularly saturated fat) can be harmful and increase the risk of diseases such obesity, heart disease and diabetes type 2. Most people should be encouraged to limit their fat intake but reduced fat diets are not suitable for children under five years as they have a relatively high energy need compared to their body size.