Why obesity is not simply about willpower

The Science Behind Obesity

Obesity is a complex condition that is shaped by a combination of biological, genetic, and environmental factors. Body weight is regulated by a complex interplay of hormones, the brain, and metabolism. In people living with obesity, this network can become disrupted, making it harder to regulate hunger, fullness, and how the body uses and stores energy.

According to Professor Sue-Anne Toh, a senior consultant endocrinologist and co-founder, CEO and medical director of Novi Health, body weight is regulated by a complex interplay of hormones, the brain, and metabolism. In people living with obesity, this network can become disrupted, making it harder to regulate hunger, fullness, and how the body uses and stores energy.

"I often see patients who experience persistent hunger, even after eating, or who do not feel full in the same way others might," she explained. "There can also be changes in how the brain responds to food, making it feel more rewarding and increasing the drive to eat."

At the same time, the body may conserve energy more efficiently, meaning it burns fewer calories for the same level of activity. "These are not simply issues of behaviour or choice," Prof Toh emphasised. "This dysregulation is a key reason why many individuals find it difficult not only to lose weight, but also to maintain that weight loss."

Why Long-term Management Matters

Left untreated, obesity can increase the risk of serious health conditions, including type 2 diabetes, cardiovascular disease, hypertension, fatty liver disease, obstructive sleep apnoea, and certain cancers. It can also reduce quality of life through reduced mobility, joint pain, fatigue, and poorer mental well-being.

Understanding obesity as a chronic disease changes how it should be managed. Like diabetes or hypertension, it requires ongoing care rather than short-term solutions. When someone loses weight, the body does not necessarily interpret it as progress. Instead, it may perceive weight loss as a form of stress – or even starvation – and respond by trying to restore the lost weight.

"Hormones that stimulate hunger tend to increase while hormones that signal fullness may decrease. At the same time, the body’s metabolic rate often slows," said Prof Toh. This makes maintaining weight loss much harder – even for people who eat well and exercise regularly.

How Obesity Treatment Has Evolved

A common misconception is that obesity treatment begins and ends with diet and exercise. "While these remain important, we now have a much better understanding of obesity and a wider range of evidence-based treatments, including medications and multidisciplinary care," said Prof Toh.

Earlier generations of weight-loss medications were often ineffective and had significant side effects. However, newer medications have been developed that can help individuals with obesity lose weight and maintain that weight loss.

In addition to medications, multidisciplinary care has become increasingly important in the management of obesity. This approach involves a team of healthcare professionals, including doctors, nurses, dietitians, and psychologists, working together to provide comprehensive care.

"This shift is important because it helps explain why many individuals struggle despite their best efforts and why effective management often requires a more comprehensive, medically supported approach," said Prof Toh.