Obesity can seem straightforward to explain. If a person consumes more calories than they need, they gain weight. But the real explanation is not that simple. And it is about more than weight.

Obesity is a complex chronic disease, and losing weight is not just a question of eating less and moving more. In fact, obesity can be influenced by genetics, physiology, environment, job and education, and what is going on in the brain.

Understanding these factors is critical, because obesity is associated with other diseases, including type 2 diabetes, heart disease and certain types of cancer. Not to mention the stigma and bias millions suffer every day.

But with the right care, people with obesity can achieve sustained weight loss that really makes a difference to their health.

Today we know that obesity is a serious chronic disease, not simply a matter of effort or willpower. 

Together with our partners, we are committed to driving change in how the world sees, prevents, and treats obesity. As leaders within the science of obesity, we are working to make obesity a healthcare priority. We do this to defeat stigma and to support better access to evidence-based care.

Obesity is influenced by many factors both inside and outside of the body. Just as someone is born with a particular eye colour, they can be born with a tendency to put on weight. In fact, up to 40% - 70% of our weight is dependent on our genetic makeup.

There is also the physiological aspect. When a person eats, hormone signals from the stomach and gut are translated into feelings of reduced hunger and increased satiety. This controls a person's food intake.

During weight loss, the level of hormones can change. The body does this in an attempt to regain the lost weight. Studies show, that 80% of lost weight is regained in the aftermath of a diet.

Many aspects of a person's general well-being, environment and lifestyle can also cause weight gain. Where a person lives, and the culture that surrounds them, can also influence the risk of developing obesity.

So, although many people with obesity believe they should be able to manage their weight on their own, the reality is not that straightforward.

To understand obesity, we must understand what is going on in our brains. It seems our bodies are hard-wired to hang on to those extra calories. Probably because for thousands of years, it was a basic survival mechanism.

Therefore, people living with obesity struggle to lose weight. Their body’s programming works to get them back to its original starting weight. In the brain, it's as if there is a switch that tweaks a person’s energy expenditure, until they have regained the lost kilos.

We are trying to pinpoint where exactly in the brain such a switch could be located. We are exploring whether it is something we could address with a medicine – so that one day, we might be able to help people with obesity to ‘reset’ their weight to a new, healthier starting point.

If we succeed, we could help millions of people living with obesity.

Obesity illustration displying a city outline.

We aim to be the leading force in the science behind obesity.

To tackle the rising prevalence of obesity, we’re taking action to stop the disease before it starts. Together with UNICEF, we’re focusing on prevention of childhood overweight and obesity. Part of that work involves shifting the narrative from individual responsibility – which places stigma on children – to the need to address environments that promote obesity from a young age.

Read more about our efforts to prevent serious chronic diseases, like obesity

In terms of treating the existing disease, we are paying close attention to the natural GLP-1 hormone. We are continuously uncovering more about the role this naturally occurring hormone appears to play in achieving successful weight loss. For example, after a person has finished a meal, the GLP-1 molecules in the body affect their feelings of hunger.

For many years, our scientists have studied how synthetic GLP-1 molecules can be used to suppress appetite or increase energy expenditure. And we will continue to examine how GLP-1 can spur long-lasting weight loss.

Currently, we are researching the following areas:

  • 20% weight reduction
  • Cardiovascular benefit