A guide to obesity and weight management

What is obesity and how to identify it?‍

According to the latest Australian Obesity Management Algorithm, obesity is “a complex and multifactorial chronic disease with genetic, environmental, physiological and behavioural determinants that requires long-term care”.¹ Simply put, this means obesity is a chronic (long-lasting) condition that is more complicated than just eating too much and not moving enough. 

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Medically, weight can be classified by the body mass index (BMI) and waist circumference (how wide around your waist measurement is; WC) as follows:^1,2

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Of course, these numbers are for the general population of Australia and slight differences or adjustments need to be made depending on your ethnicity, age and gender.¹ 

Calculating your BMI is simple, it’s just your body weight, divided by your height squared.³ For example:

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• If you were 174 cm tall, (1.74 m), then your height squared would be 3.0276 (1.74 x 1.74 = 3.0276)
• If your body weight was 75 kg, then your BMI would be 75 divided by 3.0276, or 24.8 kg/m², which is in the normal range

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Don’t worry if maths isn’t your strong suit - there are plenty of online calculators that can figure out your BMI for you. You can also complete our online questionnaire here that includes calculating your BMI. 

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Measuring your WC is also simple. Your waist is halfway between the top of your hip bone and the bottom of your ribs. To measure your WC, place a tape measure halfway between these points, breathe out normally and then read the measurement.⁴ If you’re not sure or confident doing this yourself, you can always ask your doctor for help. 

What causes obesity?‍

As mentioned above, obesity is a complex condition.¹ Ultimately, obesity happens as a result of energy intake exceeding energy expenditure over a long period of time.⁵ But it is more complicated than just eating less and moving more.  It can be caused by a lot of different things and not all of them are related to eating and exercise. Some causes of obesity can come from your genetics, early life experiences, your environment, medications you may take or health conditions you may have, even your psychology.^5,6 

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Of course, diet still plays an important role. If you think about how humans evolved, and how the availability and contents of food has changed, it’s no wonder that obesity has become a global issue.⁷ This is because diet and how our brains control hunger and cravings are connected. Our reward system in the brain has evolved to respond to calorie-dense food (from back when food was hard to find), but there is an abundance of ultra-processed, calorie-dense foods available these days that constantly stimulate this reward system. This leads to the reward system overtaking the control of hunger and eating behaviour and leading to things like food addiction and overeating which then contribute to obesity.⁷

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What are the potential management options for obesity? ‍

The goal of managing obesity as a condition is to help prevent, treat or reverse complications of obesity (like high blood pressure or diabetes) and improve quality of life.⁸ The good news is that health benefits can be seen with even a 5% loss in body weight.⁸ There are various options available to help you get there, ranging from lifestyle interventions to surgery.

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Lifestyle interventions are always recommended.¹ No matter what other options you explore, these will make up a part of your weight management. Basically lifestyle interventions mean improving the quality of your diet (different to a restrictive diet) and increasing physical activity.¹ For example, increasing the variety of vegetables, fruits and meat you eat to ensure you are getting the right amount of nutrients. Also limiting your intake of foods high in saturated fat, added salt or sugar.⁹

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Reducing energy intake is an option where you take in less energy than you expend.¹ Basically this is where you eat fewer calories, either as part of a commercially available meal plan, as part of a program with a dietitian or your doctor, or by using specially formulated meal replacements. This option should not be done without supervision of a healthcare professional as there are some cases where it may not be appropriate (during pregnancy, for example).¹

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Increasing energy expenditure means increasing physical activity, particularly anaerobic-resistance type exercise.¹ This could include weight lifting, circuit training, pilates or yoga (to name just a few). If choosing this option it’s a good idea to see an exercise physiologist to help put together a program for you.¹

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Medications are the next option to include if lifestyle interventions, reducing energy intake and increasing energy expenditure have not worked.¹ Medicated weight loss options that are available work in different ways, such as:^1,10

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• Helping to reduce feelings of cravings
• Helping to suppress your appetite
• Helping to reduce the amount of fat your body absorbs 
• Helping food stay in the stomach a bit longer  

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It’s important to know that weight loss medications are not a quick fix, and that they are intended to be used in conjunction with diet and exercise.¹ It is also essential to understand that there is no perfect medication – what works for one person may not work for another.  Your doctor is best placed to advise on which approach might be most suitable for you.

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Bariatric surgery should be considered as one part of obesity treatment.¹ This means it should not occur alone, but in conjunction with lifestyle interventions and with the help of a multidisciplinary healthcare team which includes dietitians and psychologists. Not everyone will be suitable for this option, so have a chat with your doctor about if it is right for you.¹

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