What is obesity?

Living with obesity or overweight means that you are carrying too much weight in the form of body fat. Living with obesity puts you in the highest weight range above what is considered healthy.

In Australia, 2 out of 3 adults and 1 in 4 children are living with obesity or overweight. Obesity is more common among disadvantaged Australians.

Obesity can be a sensitive topic. It is important to remember that living with obesity is not just about appearance. Obesity increases your risk of many serious physical and psychological health problems.

What are the signs of obesity?

The most visible sign of obesity is excess body fat.

What causes obesity?

You may become overweight or obese if you consume more energy in the foods you eat and drink than what your body uses. Your body stores the extra energy as fat.

Foods and drinks contain energy (measured in kilojoules) which your body uses for essential bodily functions such as growth, repair, digestion and movement. More energy is used during physical activity. The average adult needs to consume about 8700 kJ each day to maintain their health and body weight.

Obesity is complex. Many factors, some beyond your control, influence your chances of living with obesity, including:

• genetics
• medical conditions and disabilities
• certain prescription medicines
• your metabolism — how efficiently your body turns food into energy

Living with mental illness can also affect your appetite and motivation to be active, or shop for and cook healthy food.

Some parts of your lifestyle and cultural background can also influence your risk of obesity, such as:

• where you live and work, and whether healthy foods are readily available
• shiftwork
• not sleeping enough
• stress
• any drugs, tobacco or alcohol you use

When should I see my doctor?

You should see your doctor if you are concerned about your weight or if you want to lose weight.

You can talk to your doctor about:

• assessing your BMI (body mass index), waist measurement and health risks regularly
• how to improve your diet
• how much and what type of exercise is appropriate for you
• whether you should do other tests or treatments for obesity-related conditions
• referral to a dietitian for professional guidance on what and how much to eat
• a referral to a mental health professional, if your weight is interfering with your sense of wellbeing

ASK YOUR DOCTOR — Preparing for an appointment? Use the Question Builder for general tips on what to ask your GP or specialist.

How is obesity diagnosed?

Your doctor can diagnose obesity by calculating your BMI (body mass index) and measuring your waist circumference. If you are diagnosed with obesity, your doctor may recommend medical tests to check your risk of some diseases, such as cardiovascular disease.

Body mass index

Your doctor will measure your height and weight to calculate your BMI. Your BMI can give an indication of overweight or obesity.

For most adults, if you have a:

• BMI between 18.5 and 24.9, you are a healthy weight
• BMI between 25 and 29.9, you are living with overweight
• BMI that is 30 or higher, you are living with obesity
• BMI that is 35 or higher, you are living with severe obesity

BMI measurement may be less accurate in certain groups of people who naturally have different muscle and fat mass. For example, standard BMI calculations are not accurate if you are:

• under 18 or older than 65 years of age
• pregnant
• an elite athlete
• of Asian or Polynesian background

Children should not use a standard BMI measure. BMI charts specific for children aged 2 to 18 years of age are available.

Read more on measuring and managing obesity in children.

If you are unsure, ask your doctor or dietitian if BMI applies to you.

NEED TO LOSE WEIGHT? — Use the BMI Calculator to find out if your weight and waist size are in a healthy range.

Waist circumference

Your doctor may also measure your waist circumference to assess your weight and risk of disease.

You are at a higher risk of obesity-related health problems, such as type 2 diabetes, heart disease and some cancers, if you have a waist circumference of 94cm or more (for males) or 80cm or more (for females who are not pregnant).

Other tests

Your doctor may measure your blood pressure, blood glucose (sugar) and lipid (cholesterol) levels to assess your risk of health conditions associated with obesity.

How is obesity treated?

If you are living with obesity, your treatment may include:

• a low-calorie diet
• increasing your physical activity levels
• weight loss medicines
• bariatric surgery

Unfortunately, there is no 'quick fix' for obesity. It can be very difficult to lose weight in a healthy way and to keep it off in the long term.

A multidisciplinary team including a dietitian, exercise physiologist, lifestyle coach or psychologist can help you achieve your goals. Together, you can make a plan that is best for you.

Looking after your mental health and keeping a positive attitude also helps.

Reducing your kilojoule intake

One way you can lose weight is to change your diet to create an energy deficit. This means to consume less energy than what your body uses. You can do this by swapping unhealthy and high-energy foods, such as fast food, processed food, sugary drinks and alcohol, for healthier foods, including:

• fruits and vegetables
• wholegrains
• legumes
• nuts and seeds
• lean meat, poultry, fish, eggs
• low-fat milk, cheese and yoghurt

Be careful of diets that encourage unhealthy behaviours or restrict certain foods completely.

If you are planning to change your diet, it may be helpful to speak with a dietitian about a food program tailored to your needs.

Increasing physical activity

The Australian physical activity and exercise guidelines have a guide on how much physical activity you need to stay healthy.

Any activity that requires more effort than usual is considered physical activity, for example, brisk walking, swimming or playing tennis.

Here are some tips to increase your physical activity in your day-to-day life:

• Take the stairs instead of the lift.
• Be active with your children.
• Take public transport or cycle to work.

You may find it helpful to join an exercise group or sports team for motivation and support.

Research shows that doing any physical activity is better than none. Doing daily physical activity is more effective than only once or twice a week. Strength or resistance training exercise (exercising with weights) at least twice a week helps boost your metabolism (how fast you burn energy) and bone health.

Weight loss medicines

Prescription medicines are available for weight loss in Australia. To maximise effectiveness, these should be used while you reduce your kilojoule intake and increase your levels of physical activity.

Weight loss medicines work in one or more of these ways:

• reducing the amount of fat you absorb from food
• suppressing your appetite
• slowing down how quickly food empties from your stomach, making you feel full for longer

Weight loss medicines have side effects and are not safe for everyone.

Talk to your doctor or pharmacist before starting a weight loss medicine to see if it's right for you. You should only take weight loss medicines as directed by your doctor or pharmacist.

Weight loss surgery

Bariatric surgery may help you lose weight by changing the way your body digests and absorbs food.

Bariatric surgery is the most effective treatment for weight loss. Your healthcare team will consider your personal medical history and situation and discuss whether surgery would be appropriate for you.

Supporting weight loss

If you've found it hard to lose weight in the past, it may be helpful to see a counsellor or psychologist who can help you with long-term changes. Techniques such as cognitive behavioural therapy (CBT) can help make it easier to lose weight. CBT teaches you to recognise when and why you eat, and to change unhelpful thoughts or thinking patterns. If you are interested in learning more, your doctor can refer you to a counsellor or psychologist.

Complementary therapies and supplements

There are many alternative treatments and pills that claim to work for obesity and weight loss. They shouldn't replace the proven methods described above. Speak with your doctor or pharmacist before taking complementary therapies or supplements that claim to help you lose weight. Even 'natural' supplements may be toxic or dangerous.

FIND A HEALTH SERVICE — The Service Finder can help you find doctors, pharmacies, hospitals and other health services.

Living with obesity

If you are living with obesity, you may experience discrimination in your workplace, university, healthcare or your personal relationships. This can put you at an increased risk of:

• bullying
• depression
• anxiety
• disordered eating
• avoiding physical activity

Obesity, eating disorders and mental health

Some people living with obesity also have an eating disorder. This may make it more difficult for them to manage their weight without extra support. Often, people with an eating disorder who are also living with obesity are not aware that they have an eating disorder.

You may find it helpful to speak with a mental health professional about your weight, particularly if your weight interferes with your work, being active or socialising.

Read more about eating disorders.

What are the complications of obesity?

Living with overweight or obesity can increase your risk of complications such as:

• cardiovascular (heart) disease, kidney disease, stroke, some cancers
• high blood pressure (hypertension), type 2 diabetes
• sleep apnoea
• joint problems — osteoarthritis, especially in the hip and knee joints, gout and joint pain
• gastro-oesophageal reflux disease (GORD)
• mental health problems such as depression and anxiety
• sexual health problems

Losing some weight, even 5 – 10% of your body weight can have significant health benefits and reduce your risk of complications.

Your doctor can assess your risk of health complications due to obesity and any other health conditions you have.

Can obesity be prevented?

Here are some steps that you can take to help reduce the likelihood of obesity:

• Eat well: Review how many high-energy, low-nutrition snack foods and sugary drinks you consume, including juice, soft drink and flavoured milk. Consider how often you get takeaway.
• Engage in physical activity: Only half of Australians do enough physical activity for good health.
• Limit alcohol: Review how much alcohol you drink — alcohol has many kilojoules with no nutritional benefits.

Stress, low mood, poor-quality sleep, changing emotions and poor access to healthy food can all cause people to take in more kilojoules than they need. Addressing these risk factors as much as possible can reduce your chance of obesity.

Resources and support

For more information and support, try these resources:

• Call GetHealthy NSW on 1300 806 258 for free phone-based health coaching to help you reach your healthy lifestyle goals.
• Dietitians Australia has nutrition information, tips and recipes to help you eat well.
• LiveLighter offers a range of tools and calculators to help you make lifestyle changes to improve your health.
• Butterfly has a podcast titled 'Under-diagnosed and poorly treated: EDs in larger bodies'.

Do you prefer to read in languages other than English?

The Victorian Government's Health Translations has fact sheets on obesity in many community languages.

The National Eating Disorders Collaboration (NEDC) has fact sheets on eating disorders translated into many community languages.

Looking for information for Aboriginal and/or Torres Strait Islander people?

Learn about the 5 different food groups at the Aboriginal and Torres Strait Islander Guide to Healthy Eating.

If you are feeling worried or no good, contact 13Yarn and connect with an Aboriginal and Torres Strait Islander crisis supporter.