Understanding Obesity: A Guide to Health, Risk, and Treatment Options

Obesity is a complex and chronic health condition that affects millions of Australians—and it’s much more than just a number on the scale. While it’s often thought of in terms of appearance, obesity has serious impacts on overall health, increasing the risk of many chronic conditions such as diabetes, heart disease, joint pain, and even some types of cancer.

In this blog post, we’ll help you understand what obesity is, how it's measured, why it matters, and what you can do to manage it.

What Is Obesity?

Obesity is defined as having an excessive amount of body fat that can harm your health. It’s not just about carrying extra weight—it's about where that weight is distributed and how it affects your body.

One of the most concerning forms is abdominal or “central” obesity, where fat gathers around the stomach area. This type is linked to a higher risk of serious health issues such as:

• Type 2 diabetes

• High blood pressure

• Heart disease

• Fatty liver disease

• Sleep apnoea

• Certain cancers

How Common Is Obesity in Australia?

Unfortunately, obesity is becoming more common across all age groups:

Children and Adolescents (ages 2–17):

• 1 in 4 children (about 1.3 million) were overweight or obese in 2022.

• Around 7% were living with obesity.

Adults (18+ years):

• 66% of adults were overweight or obese.

• 32% had obesity.

• 13% had severe obesity (BMI over 35).

Obesity is more common as we age, and both men and women are affected.

Health Risks Linked to Obesity

Carrying excess weight increases the risk of many health problems, including:

• Heart conditions (e.g., high blood pressure, high cholesterol, heart disease, and stroke)

• Type 2 diabetes

• Breathing problems like sleep apnoea

• Joint pain and osteoarthritis

• Certain cancers (e.g., breast, bowel, kidney)

• Liver and kidney disease

• Mental health issues such as depression and anxiety

Obesity can also increase the risk of complications from infections like COVID-19.

How Is Obesity Measured?

1. Body Mass Index (BMI)

BMI is a widely used tool to estimate body fat based on height and weight.

BMI	Classification	Health Risk
<18.5	Underweight	Low
18.5–24.9	Healthy weight	Average
25–29.9	Overweight	Increased
30–34.9	Obese (Class 1)	Moderate
35–39.9	Obese (Class 2)	Severe
40+	Obese (Class 3)	Very severe

However, BMI isn’t perfect. For example, muscular individuals may have a high BMI without having too much fat.

2. Waist Circumference

Fat around the belly (visceral fat) is especially risky. A high waist measurement can signal higher risk for diabetes, heart disease, and more.

Waist (cm)	Risk Level
Men ≥ 94 / Women ≥ 80	Increased risk
Men ≥ 102 / Women ≥ 94	High risk

3. Body Fat Percentage

This measures the actual fat content in your body and may be a more accurate health indicator than BMI alone.

What Causes Obesity?

Many factors contribute to obesity, including:

• Genetics: Some people are more likely to gain weight based on how their body stores fat.

• Diet: High-calorie foods, sugary drinks, and alcohol play a big role.

• Activity levels: Sedentary lifestyles make it harder to maintain a healthy weight.

• Medications: Some medicines (like antidepressants, corticosteroids, and diabetes medications) can cause weight gain.

• Mental health: Stress, depression, and emotional eating are common contributors.

Setting Realistic Goals

It’s important to remember that even small weight losses (5–10%) can significantly improve your health.

Health improvements from modest weight loss:

• Lower blood pressure

• Better blood sugar control

• Improved cholesterol levels

• Reduced joint pain

• Better sleep and mental health

Treatment Options for Obesity

Managing obesity is a journey—and there’s no one-size-fits-all solution. A multi-factor approach often works best.

1. Lifestyle Changes

• Diet: Focus on healthy, balanced meals. Portion control and cutting down on processed foods help.

• Exercise: Aim for regular activity (e.g., walking, swimming, cycling). Start small and build up.

2. Medication

For some people, medication can support weight loss, especially when other methods haven’t worked. Options available in Australia include:

• GLP-1 receptor agonists: such as semaglutide and tirzepatide.

• Other medications: such as bupropion/naltrexone or phentermine.

  
  

A new oral option called orforglipron (not yet widely available) may offer easier access in the future.

3. Meal Replacements

Products like Very Low Energy Diet (VLED) shakes or bars can be used short-term under medical supervision.

4. Surgery

Weight-loss surgery (such as gastric bypass or sleeve gastrectomy) may be considered for those with severe obesity or related health problems.

What to Expect From Treatment

Weight loss isn’t always fast—but consistency matters more than speed. Set realistic goals, such as:

• 1–2 kg loss per month

• 5–10% total weight loss in 6–12 months

• Lower waist circumference

And remember: success isn’t just about the scale. It’s about improved energy, better sleep, reduced medications, and better overall health.

Takeaway

Obesity is a medical condition—not a personal failure. It’s influenced by many factors and often requires professional support to manage. If you're concerned about your weight or health risks, speak with your GP about a Home Medicine Review to support your weight loss.