As our latest guest in the WU Research Seminar Series, we were delighted to welcome Anirban Mukhopadhyay from Bayes Business School, City University of London. He presented his compelling research on lay beliefs about food, behavior, and the global obesity crisis.

In his talk, “Beliefs, Behaviours, and Body Mass,” Professor Mukhopadhyay examined how people’s intuitive beliefs—such as “unhealthy food tastes better” or “exercise matters more than diet”—impact health outcomes and decision-making. Despite medical consensus that poor diet is the primary driver of obesity, only about half of the public believes this. His research shows that individuals who instead blame lack of exercise are more likely to have higher body mass indices (BMIs).

In Austria, for example, 52% of adults are now overweightor obese, a trend that reflects the very beliefs and behaviors his work investigates.

A key driver of these misperceptions is leanwashing—corporate messaging from food companies that shifts the blame for obesity away from their products and toward consumer inactivity. From public statements to sports sponsorships, firms like Coca-Cola and McDonald’s actively promote the idea of a “balanced active lifestyle” to deflect attention from unhealthy ingredients.

Professor Mukhopadhyay presented findings from large-scale international studies showing that belief in the Unhealthy = Tasty Intuition (UTI) leads to lower consumption of fruits and vegetables and, ultimately, higher BMI. In a follow-up study across four countries, he demonstrated how parents who endorse UTI beliefs often use food rewards to promote healthy eating—an approach that can backfire and lead to higher BMI in their children.

Framing the obesity crisis as a market failure, he argued for stronger food policy and regulation to counteract asymmetric information, externalities, and industry influence.

He closed by sharing new directions in his research, including the intersection of leanwashing with environmental messaging, and how parental beliefs affect children's mental health and behaviors.

Thank you, Anirban, for your engaging and thought-provoking talk—we were thrilled to host you at WU Vienna!