Many of us have grown up hearing that obesity is simply about eating too much or not exercising enough. We now know it’s much more complicated than that.
Obesity is a chronic disease. Obesity is caused by biological, psychological, genetic, hormonal, and environmental factors. All of these factors influence how our bodies regulate hunger, fullness, energy use and body weight.
Understanding this is important. It helps explain why losing weight can be so difficult, and why keeping weight off can be even harder. It also reminds us that living with obesity is not a personal failure or a lack of willpower.
If you’re thinking about bariatric surgery, it’s helpful to understand that surgery is a treatment for obesity rather than a cure. It can be an excellent tool, but it works best alongside ongoing support, good nutrition, regular follow-up and other lifestyle changes.
What is obesity?
Obesity is diagnosed when carrying excess body fat begins to affect health. A body mass index (BMI) of 30 kg/m² or above is often used to diagnose obesity, but BMI is only one part of the picture. It doesn’t tell us everything about a person’s health.
Living with obesity can increase the chance of developing conditions such as type 2 diabetes, heart disease, sleep apnoea, fatty liver disease, osteoarthritis and some cancers.
Body weight is influenced by far more than what we eat. Our genes, hormones, medications, sleep, stress, mental health, physical activity, health conditions and surroundings all play a part. The brain is constantly regulating hunger, fullness and energy use, making body weight much more tightly controlled than many people realise.
Why obesity needs long-term treatment
Like asthma, diabetes or high blood pressure, obesity is a long-term health condition. It usually needs ongoing treatment rather than a short-term fix.
Success doesn’t always mean losing large amounts of weight. For some people, preventing further weight gain is a very positive outcome. For others, losing a relatively small amount of weight can make a real difference to health.
Research shows that losing around 5 to 10% of body weight can help improve blood glucose levels, lower blood pressure and reduce the risk of other obesity-related health problems. Even modest changes can have meaningful health benefits.
Why is it so easy to regain weight?
Many people blame themselves when weight comes back after dieting. In reality, this is a normal biological response.
When you lose weight, your body tries to protect itself against further weight loss. Your metabolism becomes more efficient, meaning you burn fewer calories than before. At the same time, hormones that stimulate hunger become stronger, while hormones that help you feel full may become weaker.
This combination means you often feel hungrier while needing fewer calories than someone of the same weight who has never lost weight. It’s one of the reasons long-term weight management can be so challenging.
This pattern, often called weight cycling or yo-yo dieting, is very common. It highlights why obesity needs ongoing support rather than repeated short-term diets.
Thinking about bariatric surgery?
If you’ve been living with obesity for many years and other treatments haven’t given you the results you hoped for, bariatric surgery may be something you’re discussing with your healthcare team.
Preparing well before surgery can make a real difference. Understanding how surgery works, what to expect afterwards, and how to nourish your body for the rest of your life can help you get the best possible outcome.
We’re currently creating an expert-led course to guide you through every stage of the journey. Whether you’re still deciding if surgery is right for you or you’ve already booked your procedure, the course will give you practical, evidence-based advice to help you feel informed and prepared.
Join the Nourished Bariatrics waiting list to be the first to hear when it launches.
