When it comes to weight and health, Body Mass Index (BMI) is a common screening tool used by Australian health professionals to assess whether a person is underweight, a healthy weight, overweight, or living with obesity. While BMI isn’t perfect – it doesn’t differentiate between muscle and fat – it remains a useful indicator of health risks, especially when combined with other measures like waist circumference.
What Is Body Mass Index (BMI)?
Body Mass Index (BMI) is a quick calculation using your height and weight to estimate your weight category — from underweight to obese.
While it’s a general guide, BMI can help assess your risk of weight-related health issues, especially when used with other measures like waist circumference. It’s often used when exploring options such as weight loss solutions..
It’s important to note that BMI is not suitable for everyone. It doesn’t apply to children, teenagers under 18, or people who are pregnant, and it should always be considered alongside other health indicators, such as waist measurement and existing medical conditions.
Ultimately, BMI is a broad guide that classifies adults into one of several weight ranges. It’s best used as a starting point when assessing potential health risks and planning personalised care.
BMI Calculator
| BMI Range (kg/m²) | Classification | Risk of Comorbidities |
| Less than 18.5 | Underweight | Increased risk of nutritional issues |
| 18.5 – 24.9 | Normal weight | Low risk |
| 25.0 – 29.9 | Overweight | Increased risk |
| 30.0 – 34.9 | Obesity Class I | Moderate risk |
| 35.0 – 39.9 | Obesity Class II | Severe risk |
| 40.0 and above | Obesity Class III | Very severe risk |
These categories are consistent with Australian guidelines used to assess weight-related health conditions.
Health Risks Associated With a High BMI
A BMI of 25 or higher is associated with an increased risk of developing a number of chronic health conditions, known as comorbidities. These include:
- Type 2 Diabetes: A high BMI increases insulin resistance, often leading to diabetes.
- Cardiovascular Disease: Conditions like high blood pressure, stroke, and heart disease are more likely.
- Obstructive Sleep Apnoea: Excess weight can impact breathing during sleep.
- Joint and Mobility Issues: Extra weight can contribute to osteoarthritis and chronic pain, especially in weight-bearing joints.
- Certain Cancers: Obesity is linked to increased risk of cancers such as breast, bowel, and endometrial cancer.
- Mental Health Concerns: People living with obesity may also face depression, anxiety, or social stigma.
It’s important to note that the risk isn’t just about weight, but where fat is carried. Abdominal obesity (measured by waist circumference) carries even greater health risks.
Why Waist Circumference Matters Too
BMI should be considered alongside waist measurements:
- For men, risk increases at 94 cm and is high at 102 cm or more.
- For women, risk increases at 80 cm and is high at 88 cm or more.
Excess fat around the stomach area is strongly linked to type 2 diabetes, heart disease, and other metabolic conditions — even if your BMI falls within a normal or slightly elevated range.
What You Can Do
Understanding your BMI is a good first step toward improving your health – but it’s not the only measure that matters. Lifestyle factors like diet, physical activity, mental wellbeing, and sleep all play an important role. If you’re concerned about your weight or its impact on your health, it’s important to seek professional support.
Ready to Take Control of Your Health?
At Complete Weight Loss Solutions in Melbourne, we help individuals living with overweight or obesity explore evidence-based solutions to improve their health – including surgical and non-surgical weight loss options. Our team is here to guide you every step of the way, with personalised care tailored to your health goals.