What is a diet?

A diet involves eating a certain selection of food, usually to improve your health, regulate your weight or cure a disease.

New diets, programs and books on losing weight appear every day. While many Australians need to lose a few kilos, it’s important to follow an eating and exercise plan that you can maintain. The plan needs to help you stay healthy for the long term.

Nearly 2 in 3 Australians are overweight or obese. Carrying extra weight increases your risk of chronic diseases like heart disease, stroke, type 2 diabetes and some cancers. If you are above a healthy weight, losing just a few kilos can lower your risk of health problems.

How can I lose weight in a healthy way?

To lose weight if you are not in a healthy weight range, you need to be physically active and follow a healthy eating plan. You should only eat enough nutritious foods and drinks to meet your energy needs.

Your healthy eating plan should include a balanced diet with foods mainly from these 5 healthy food groups:

• different coloured vegetables
• fruit
• whole grains
• lean meats, poultry, fish, eggs, tofu, nuts, seeds, legumes and beans
• milk, yoghurt and cheese (with mostly reduced fat)

You should limit your intake of foods that contain saturated fat and added sugar and salt.

To lose weight healthily, you should also:

• limit your intake of alcohol
• drink plenty of water
• cut down on takeaway
• eat regularly
• eat healthy snacks
• choose smaller portions
• eat breakfast
• enjoy a wide variety of foods
• eat plenty of fibre to fill you up
• eat more vegetables

Your healthy exercise plan means you should be physically active on most, if not all, days of the week. For adults, this includes either or a combination of the following:

• 2 ½ to 5 hours of moderate physical activity per week — such as a brisk walk, golf, mowing the lawn or swimming
• 1 ¼ to 2 ½ hours of vigorous physical activity per week — such as jogging, aerobics, fast cycling, soccer or netball

Make sure you include muscle-strengthening activities such as push-ups, pull ups, squats, lunges or weights in your plan.

You can build physical activity into your day, for example, by taking the stairs instead of the lift, or by walking or cycling rather than driving. It is also important to limit the amount of time you spend sitting.

What is a ‘fad’ diet?

A 'fad' diet is an eating plan that usually promises rapid weight loss. All fad diets have one thing in common — they propose a temporary solution to what is a lifelong problem for many people.

Fad diets are often advertised through the media. They are generally not based on science or do not have a lot of clinical research to back up their claim. Often, fad weight-loss diets want you to cut out entire food groups, which could mean you do not get all the nutrients that your body needs.

You should not confuse fad diets with vegetarian or vegan diets. These are not weight-loss diets and, with good planning, vegetarians and vegans can get all the nutrients they need.

What are the risks of fad dieting?

It is important to realise that not all fad diets work, and some can be potentially harmful. Going on a restrictive fad diet can lead to:

• slowing of the body's metabolism — how quickly you burn kilojoules —, which means you will put on weight easily in the future
• constant feelings of hunger, leading to food cravings and an increased appetite
• rapid weight loss followed by rapid weight gain
• an eating disorder, such as anorexia nervosa or bulimia
• less muscle tissue and lower bone density
• headaches, insomnia and fatigue
• lower body temperature
• constipation or diarrhoea

Most of the weight you lose on a fad diet is water and lean muscle, not fat. That is because when you eat too little, your body breaks down muscle to get enough kilojoules. It is easier for your body to get kilojoules from muscle than from fat.

How do I spot a fad diet?

Fad diets are popular in Australia. Common fad diets include those that:

• promote fast weight loss without supervision by a dietitian or a doctor
• focus on short-term changes to your eating or exercise
• include pills or preparations

You might lose weight in the short term on fad diets, but they are difficult to keep doing. They can cause serious health problems. The best approach to weight loss is to follow a long-term, balanced eating plan and to exercise regularly.

What else can I do to keep a healthy weight?

Here are 5 actions you can take to help keep a healthy weight:

1. Plan your weekly shop before you go to the supermarket. Healthy, balanced meals are key to keeping a healthy weight. Eating a balanced diet often starts with having the right foods at home.
2. Swap foods and treats that are high in calories, fat, salt and sugars for healthier and home-made alternatives.
3. If you do order takeaway food, choose the healthiest options. LiveLighter has ideas on how to swap high-kilojoule meals for healthier choices.
4. Commit to one more way to increase your level of physical activity. Adults should do at least 30 minutes of moderate-intensity physical activity on all days of the week, if possible. This could include fast walking or cycling. You may need to do more to lose weight. Speak to your doctor for advice.
5. Identify the week’s danger zones. These are times when you might find yourself eating lots of foods that are high in fat and sugar because you are eating out or feel tired or stressed. Plan your week so that you can limit those foods. But don’t be too strict — an indulgence from time to time is fine.

Consider using a health and coaching service that may be available free in your state. For example, there are free Get Healthy services in New South Wales and South Australia.

Resources and support

• Talk to your doctor.
• Read the Australian Dietary Guidelines
• Read Australia’s Physical activity and exercise guidelines
• Find an accredited practising dietitian from the Dietitians Association of Australia, or call 1800 812 942.
• Call the healthdirect helpline to speak with a registered nurse on 1800 022 222.