"The Madrid Global Obesity Summit: 1.1 Billion People Living With Obesity and a Call to Action Due October 28"

Madrid is hosting a summit this week about a condition that now touches one in seven people on Earth. The Madrid Global Obesity Summit opened on Monday, co-hosted by Spain's Ministry of Health and the World Health Organization, with UNICEF and the World Bank alongside, and it runs until Thursday. It is a stocktaking moment under the WHO Acceleration Plan to Stop Obesity, the plan member states endorsed in 2022 — and the numbers it is taking stock of are bleak.

According to WHO's latest data, 1.1 billion people were living with obesity in 2024: 940 million adults and 170 million children and adolescents aged 5 to 19. Another way to put it: 45% of all adults were overweight, adult obesity has more than doubled since 1990, and adolescent obesity has quadrupled. Higher-than-optimal body weight contributed to an estimated 3.7 million deaths in 2023, through cardiovascular disease, diabetes and cancers. Left alone, the World Obesity Federation projects the costs of overweight and obesity reaching US$3 trillion a year by 2030.

What makes this summit different from the many health summits before it is that, for the first time, the world has both a widely agreed framing and a genuinely effective treatment. Obesity is now described by WHO as a chronic disease driven by environments, biology and behaviour together — not a failure of willpower. And in December 2025 WHO published its first guideline on GLP-1 therapies for obesity in adults, the drug class behind semaglutide and tirzepatide, recommending them as one component of broader care, not a standalone fix.

But the gap between knowing and doing is the whole story. The Acceleration Plan has 34 frontrunner countries covering 1.3 billion people, a third of everyone living with obesity. The World Obesity Federation's assessment is blunter: only about 7% of health systems are adequately equipped to manage obesity, and around two-thirds of countries have put in place one or none of five key prevention measures. The fastest growth is now in low- and middle-income countries, where clinics face the double burden of undernutrition and obesity at once.

So the summit's real test comes on Wednesday, 28 October, when it closes with a Global Call for Accelerated Action to Stop Obesity, in a high-level session livestreamed by WHO. Calls like this are easy to write and easier to forget; their language is usually negotiated down to whatever offends nobody. What would make this one different is numbers: a count of countries signing on, a dated target, a pledge with a deadline. The Acceleration Plan already gives the framework; the Call has to give the commitments.

I am watching for one thing in particular: whether the Call treats the new weight-loss drugs as part of public health systems or leaves them as a private luxury. GLP-1s work, but at current prices they mostly reach the wealthy, which would turn a medical breakthrough into another inequality engine. A Call that says nothing about access will have said, in effect, that the summit was a conference, not a turning point.

One in seven people. That is the number this summit has to answer to, and by Thursday we will know whether its answer came with numbers of its own.