Last partial update: August 2022 - Please read disclaimer before proceeding.
Dietary nutrient groups
The nutrients in food are divided into two main groups; those present in large amounts, called macronutrients, and those in small amounts, called micronutrients. The macronutrients consist of carbohydrates, fats, fibre and protein, while the micronutrients consist mainly of vitamins and minerals. The table below indicates the energy content and functions in the body of each of these groups. The roles nutrient groups play in causing and preventing illness in Western society are discussed in detail throughout this book. It needs to be emphasized that the majority of Australian diets are not nutrient deficient. In fact, most Australian diets contain too much energy and too much fat. There are, however, a few groups of people who are likely to have micronutrients deficiencies. This issue is discussed in the sections on micronutrients, vegetarian diets, and osteoporosis. The role of antioxidants in disease prevention is also discussed later in this section.
Function and energy content of nutrient groups
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Nutrient |
Foods sources |
Energy content |
Function / use |
|
cal |
kJ |
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Fat - Fatty acids |
Mainly animal sources and vegetable oils. |
9 |
37 |
Mostly stored as fat for later energy use by the body when needed. Also an integral part of cell membranes. |
Fat - Cholesterol |
Lambs brains, liver, eggs and some seafood. |
Synthesis of body compounds including cell membranes and body chemicals, such as steroid hormones. |
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Alcohol |
Alcoholic beverages |
7 |
29 |
Used for energy. Alcohol is not converted to fat but is metabolized to provide energy before fat and thus reduces the rate of fat breakdown. |
Protein |
Meats, fish, poultry, eggs, milk products, cereals, nuts and legumes, including soy beans, lentils, beans and peas |
4 |
17 |
Mostly used in the synthesis of body components. Only rarely used as an energy source, such as in starvation. |
Carbohydrate - Starches (complex carbohydrates) |
Pasta, potato, breads, cereals, fruit, legumes |
4 |
16 |
Provides energy for the body’s functions and some energy storage. It is usually stored as glycogen in the liver (and the muscle) but may be converted to fat if consumed in excess. (Glycogen is just many glucose molecules joined together.) The sugar that circulates in the blood and provides energy for the body is glucose. The brain relies almost solely on this glucose for energy and thus it is very important for blood glucose levels to be maintained. |
Carbohydrate - Simple sugars (sucrose, glucose, fructose, lactose) |
Fruit, honey and other sweet syrups |
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Fibre |
Bread, cereals, vegetables, fruit. |
0 |
0 |
Fibre keeps the bowel functioning normally and has a role in protection of the bowel from cancer causing substances. Soluble fibre can reduce blood cholesterol levels. |
Vitamins and minerals |
A wide variety of foods is needed, especially vegetables, fruit, low-fat dairy and lean meat. |
0 |
0 |
They are essential for the synthesis of many body components, especially enzymes. These nutrients have no significant energy function. Some are also important antioxidants. |
Water |
Fluids, fruit and vegetables |
0 |
0 |
70% of the body is composed of water. |
The major groups listed in the above table (and other nutrition topics) are dealt with in detail in other sections of this web site. (Links to these sections are listed below.)
Major dietary health dilemmas
a. Body energy imbalance and obesity - Australians eat too much
One of the major problems associated with our modern, technologically-based society is that it has dramatically altered our body’s energy balance, unfortunately for the worse. We are doing less physical activity and have less time to prepare nutritious foods, relying instead on prepared food that usually has a high energy content. This combination of using less and consuming more energy means that many people have an energy intake in excess of their needs and this excess energy intake is stored as fat. And excess body fat (i.e. obesity) causes about 7.5% of all illness in Australia.
The contribution made by the different nutrient groups to this energy imbalance varies according to their energy content, with dietary fat being the main culprit. Table 8 shows that fat and alcohol have significantly higher energy content (per unit weight) than carbohydrate and protein. In addition to having a lower energy content, carbohydrates use up more body energy in the processes of being digested, stored (as fat or glycogen in the liver), and released for use in the body than fat does. It is an easy and efficient process for the body to store excess energy from dietary fat as fat in the body. The equivalent of only about 3 per cent of the energy provided by dietary fat is used in its storage as body fat. In contrast, about 25 per cent of the energy contained in the carbohydrate is used up in the process of converting it to stored fat. This is a much less efficient process and means that less fat will be created if excess energy is consumed in the form of dietary carbohydrate rather than dietary fat.
While alcohol is generally not stored as fat, the energy it provides means that less energy from dietary fat or dietary carbohydrate is needed for the body’s immediate energy demands, resulting in more being available for fat storage. Protein is rarely used to supply body energy. Starvation is one such time.
In an optimum diet, carbohydrate, mostly in the form of starch, contributes about 55 to 60 per cent of dietary energy intake and fat about 25 to 30 per cent. The other 15 per cent comes from protein. The contribution from alcohol varies according to consumption. Unfortunately, in modern western diets, the energy contribution from fat is more in the region of 35 per cent and the overall energy intake from all nutrients is excessive.
Reversing this energy imbalance is a major preventative health dilemma facing many Australians. It is dealt with in Part 5, Obesity and Physical Inactivity.
In the end, losing weight through diet means eating less energy. There are many weight loss diets out there and most rely on reducing energy intake by reducing carbohydrate or fat intake or both. Choosing one you like and can keep to is the task. And reducing the amount of food eaten has been shown o be one of the best ways to increase longevity.
b. Lack of fruit and vegetables
Fruit and vegetables are an important source of many nutrients, including vitamins, minerals and antioxidants.
The recommended daily intake for Australian adults is five servings of vegetables and two servings of fruit and unfortunately few Australians achieve this aim. In 2015 roughly 50% of adults and 67% of children eat the recommended amount of fruit but only 7% of adults and 5% of children consume the recommended intake of vegetables. Lack of fruit and vegetables causes about 2.1% of all illness in Australia, mostly by increasing heart disease. (Two-thirds of this illness occurs in men as they eat less fruit and vegetables and have more heart disease.)
Another important benefit from vegetables is that many have a low energy content and substituting these for high energy foods in main meals can significantly reduce energy consumption and thus weight. For example, substituting potatoes rice and pasta (high energy foods) with carrots, broccoli and peppers will reduce the energy content of a meal without reducing food quantity.
Source – Adapted from Australian Institute of Health and Welfare: Begg, S. et al: 2007. |
c. Consuming too much fat and especially too much saturated fat
Australians, in general, consume too much fat in their diet. Fat is an energy dense nutrient and its excessive consumption increases weight / obesity risk.
Australians also consume too much saturated fat. This mostly comes from animal sources of fat, although there are some significant non-animal sources that are mostly used in the production of processed foods (e.g. coconut oil, palm oil, unsaturated vegetable fats that have been artifically modified to saturated fat.). See section on fats. (It is worth noting that about 27% of the landmass of the planet is devoted to raising cattle; an area the size of Africa. Eating less meat would reduce further land clearing and reduce green house gass emmissions. It's good for you and good for the planet.)
Diets with high intakes of saturated fat are associated with raised blood cholesterol and also causes inflamation in the body, both of which cause illness including heart disease. However, this is an association and evidence that it is saturated fat that causes the raised cholesterol and heart disease is lacking. The association between a diet high in saaturated fat and high cholesterol levels / heart disease has in the past led it to being seen as a cause for cardiovascular disease (heart attaks and strokes) but this lack of evidence of a causal effect has meant there is some disagreement as to whether saturated fats do directly cause heart disease. (There is no doubt that high cholesterol levels (mainly LDL cholesterol) causes heart disease and that lowering it with medication reduces heart disease.) However, there is general agreement in the medical community that the best type of diet for your health is a Mediterranean diet that is relatively low in saturated fat and high in mono-unsaturated fats and poly-unsaturated fats.
The messages with respect to healthy fat intake.
1. Reduce total intake to healthy levels
2. Substitute momo-unsaturated and poly-unsaturated fats for saturated fats: While just lowering saturated fat in the diet has been of questional benefit in reducing heart disease, diets that substitute mono-unsaturated fats and poly-unsaturated fats for saturated fats have been shown to reduce heart disease. This is the best option when trying to reduce heart disease.
3. Avoid trans-fats: Medical authorities also agree that trans-fats are deleterious for your health and should be avoided. They mostly occur in processed foods.
See the section on Fat in the Diet for more information about the types of fat Australians consume.
d. Consuming too much alcohol
Many Australians consume at levels that cause harm.
See section Alcohol - Avoiding Harm from use in adults
e. Consuming excessive sodium (salt)
See section on salt in the diet
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Suggestions for a healthy diet
There are many nutritional factors that require consideration in formulating a healthy diet and these will be discussed in the rest of this section. Below is a table summarising what most nutritionists and dietitians would consider a healthy diet.
Meals should be made from fresh produce as much as possible as it is the only way to tell what is really being eaten. Processed foods / take away foods should be restricted / used as treats or avoided.
Recommended food intake for a healthy diet
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Bread, pasta, potatoes (prepared without fat), grains
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Meat, fish, chicken, eggs, legumes and vegetable poteins (such as tofu): Meat must be lean with all visible fat removed and chicken should be skinless.
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Vegetables
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Fruit
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Nuts (unsalted)
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Milk products
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Fats and oils
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Indulgences
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Fluids
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Mediterranean diet
The Mediterreanean diet has been shown to reduce the incidence of cardiovascular disease (heart attacks and strokes) and death rates overall. There is also evidence that it reduces the incidence of numerous types of cancer (including bowel and prostate cancer), Parkinson's disease and even Alzheimer's disease and depression.
The key components of the Mediterreaean diet are as follows:
- Eating primarily plant-based foods such as fruits, vegetables, whole grains, legumes and nuts. Dried fruit and nuts are good as snacks.
- Replacing animal-based fats such as butter and cream with healthy fats such as olive oil and canola oil (Low fat dairy products, especially milk (but also yoghurt / cheese), are still a good sources of calcium.)
- Using herbs and spices rather than salt to provide flavour
- Eating poultry and especially fish at least twice a week
- Limiting red meat to once a week and keep portions small; and avoid processed meats
- Restricting alcohol consumption to healthy levels (Maximum of one standard drink per day for women, two for men and having at least two alcohol-free days per week.)
- Avoid sugar-based drinks and limit eating sweets tospecial occasions.
It is important to remember that the diet is based on everyday foods; not foods commonly eaten as treats or at celebrations. It is based on a largely vegetarian diet with little meat. In fact it has more fish than meat.
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The Meditteranean diet food pyramid.
Resource: TheMediterranean Diet by Dr Catherine Itsiopoulos
Consumer food information
Almost all packaged foods in Australia have a nutrition label. It shows the ingredients and the presence of common food allergens. It also provides information about the nutritional contents, including energy, fat, protein, saturated fat, sugars and sodium. This is expressed as the amount in a usual serving of the product and in 100g of the product.
By looking at the content of total fat, saturated fat, energy and sodium, people will be able to determine whether the food is detrimental or beneficial addition to their diet. Hopefully, where appropriate, many packaged foods will also provide the fibre content and the glycaemic index on their labels to aid in purchasing decisions. With regard to unlabeled foods, food nutritional guides, together with the comments on the fat and energy content of foods in this book, should enable an informed judgement regarding the food’s nutritional value.
An example of a typical nutritional label appears below and, as stated above, the nutrients, such as saturated fat, are shown as two different amounts. Different food items in the same group of foods will often have different serving sizes and the best way to compare nutritional values in similar items, such as butter and margarine, is to look at the quantity of the nutrient in 100g of the product.
The amount of in a typical serving is there to help people calculate how much of the ingredient they will consume when eating a typical serving. The quantity of product in a typical serving is also stated. It is important to recognize that the typical servings quoted are only a guide, as your portion size may vary significantly from this level. (Some manufacturers suggest unrealistic portion sizes to hopefully increase consumption of their product.) People need to weigh the portion on their plate to calculate its energy and fat contents accurately.
Example of an Australian food label
Nutritional information |
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|
Quantity |
Quantity |
Energy |
608kJ |
405kJ |
Ingredients: Whole milk, concentrated skim milk, sugar, strawberries (9%), gelatine, culture, thickener (1442). |
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PRODUCT OF AUSTRALIA |
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Best before 1 APR 10 |
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Food shopping
There are now well over 15,000 different food items available at a large supermarket store and making choices while ‘strolling the isles’ can be very difficult.
Here is some advice.
- Plan ahead. Planning the week’s meals ahead allows people to go to the supermarket with a list of what they need and means unhealthy food choices can be eliminated before going to the store. It helps to have a range of main meals to choose most meals from, say at least 20, and then perhaps have one or two days a week where something different is tried.
- Try to avoid buying prepared foods when ever possible. Making sauces etc from scratch makes them tastier and is usually not too difficult; and its the only way to know what is in them.
- Do not be tempted by displays and advertising in the store. They are mostly unhealthy foods.
- Avoid buying unhealthy drinks. These include soft drinks and juices with added sugar. (All juices have some sugar and juices with no added sugar can be had in moderation.) Preferred drinks should be water and low-fat, calcium-enriched milk.
- Avoid buying problem ‘treat’ foods for the pantry. These include confectionary, cakes, biscuits, and most energy / fruit bars. This does not mean no treats. It just means that treats should be just that; something bought (or made at home) occasionally.
- When choosing between similar items, such as brands of tinned tomatoes or margarines, use the product information label to help in making the most nutritious choice. (See above.)
Caffeine
Caffeine is a commonly used drug!! About 450 billion cups of coffee are consumed in the world each year and coffee is the second most traded commodity in the world after oil. On average Australians consume about 2.3kg of caffeine per year.
Caffeine is a central nervous system (brain) stimulant drug that causes a mild increase in alertness, concentrating ability, mood, heart rate, metabolic rate and passing of urine. This increase in alertness decreases with time and thus people need ever increasing doses to achieve the same effect (i.e. dependence develops).It does not improve problem solving ability or intellect. Its effects occur about 15 to 45 minutes after consumption. It is addictive and chronic intake at higher doses can cause palpitations, tremors, insomnia, flushing, agitation, gastroesophageal reflux, and anxiety. There is also evidence that it causes detrimental affects with respect to learning and motivation in young people. In order to help avoid these symptoms, it is wise to restrict caffeine intake to no more than 200-250mg per day; the equivalent of about 2-3 cups of coffee or 4-5 cups of tea. Regular consumption of more than 350mg per day leads to dependence and ceasing use causes a short-term withdrawal syndrome characterized by irritability, headache, restlessness, insomnia, fatigue, poor concentration, temporarily depressed mood, and muscle stiffness. When cutting down on caffeine, doing it slowly will help minimize these symptoms.
Pregnant women should also keep to low intakes as high intakes have been associated with an increased incidence of miscarriage and stillbirths.
Coffees do vary somewhat in their caffeine content while all teas contain about 3 per cent caffeine. Decaffeinated coffee and tea contain only 0.3 per cent caffeine. New energy drinks also contain high levels of caffeine. This comes from guarana, a compound found in the seeds of a vine from the central Amazon. Drinks containing guarana are not appropriate for children. Guarana is also used occasionally in some fruit juices available from ‘fruit juice bars’. The caffeine helps to entice people back for more.
Caffeine can cause increased stiffening of your arteries, which can increase blood pressure. People who have high blood pressure may be well advised to restrict coffee intake to one or two cups per day or use decaffeinated coffee.
Sources of caffeine:
The commonest sources of caffeine are, in order of content per serving, strong espresso (up to 120mg), fresh coffee (80-90mg of caffeine), energy drinks such as ‘Red Bull and ‘Black Stallion’ (80mg to115mg), instant coffee (60-90 mg), strong tea (50-60 mg), 375ml cans of cola drink (30-50 mg), weak tea (20-30 mg) and chocolate products, including cocoa, hot chocolate and chocolate bars.
Unfiltered coffees (including decaffeinated coffee) can raise cholesterol slightly, mainly because lipids in the coffee are not removed (by filters). Filtered and instant coffees appear not to have this effect.
As stated above, caffeine causes anxiety like symptoms, such as palpitations, tremors and sleep disturbances, especially when taken to excess by adults or when taken by children. Both cola drinks and new energy drinks are high in caffeine and calories (energy) and children and adolescents should avoid them. Currently, their consumption in young people is high and increasing, which is very unfortunate as young people already suffer significantly from as obesity, mild anxiety and attention deficit hyperactivity disorders; and this consunption will make these problems worse. (Some cola drinks are unsweetened and these do not contribute to the obesity problem.) All cola drinks are also quite acidic and this causes erosion of tooth enamel.
Ready mixed drinks containing alcohol and caffeine
Recently caffeine has been mixed with alcohol in drinks targeted at teenagers. This is unfortunate as the stimulant effect of the caffeine masks the depressant effect of the alcohol. Usually this alcohol depressant effect acts to reduce alcohol consumption and thus protect the individual from excess alcohol consumption. Thus, the addition of caffeine means the person consumes more alcohol (obviously the whole idea behind the product) and becomes more intoxicated, resulting in less coordination and less inhibition.
The combination of the stimulant effect of the caffeine and the inhibition from the alcohol means that males especially are more likely to involved in violence. Also, there is some evidence indicating that people who drink these products have been shown to be more likely to be involved in a motor vehicle accidents or be the victim of a sexual assault. Time for a quote!!
‘The health and wellbeing of young people is a critical measure of a society for two reasons: in moral terms, how well a society cares for its weak and vulnerable is a measure of how civilised it is; in more pragmatic terms, a society that fails to cherish its young, fails. It’s as simple as that.’
Richard Eckersley, Australian scientist and author.
Further information
Nutrition Australia
www.nutritionaustralia.org
A non-government, non-profit, community-based organisation that has offices in all states and territories. It aims to promote the health and well-being of all Australians.
Food Standards Australian & New Zealand (FSANZ)
www.foodstandards.gov.au
Provide current recommendations regarding food standards in Australia. Lots of good information.) Ph 02 - 6271 2222
OzFoodnet
http://www.ozfoodnet.gov.au
A health network designed to enhance the surveillance of food-borne diseases in Australia.
TheMediterranean Diet by Dr Catherine Itsiopoulos
Further information on food allergies
FARE - Food allergy Research and Education
www.foodallergyalliance.org
Australasian Society of Clinical Immunology and Allergy
www.allergy.org.au