Emulsifiers are among the most common food additives found in ultra-processed foods (UPFs), a much-discussed category of foods commonly defined as those made using manufactured ingredients. They are often packaged and have a long shelf life. Research examining the impact of diets high in UPFs suggests higher rates of obesity and diseases such as type 2 diabetes, heart disease, and cancer.However, discussions about labeling these foods as "ultra-processed" have also sparked debates about whether their negative effects are primarily due to their high fat, sugar, and salt content, or whether they stem from the effects of processing itself, particularly the additives they contain.In this episode, Jaega Wise explores one of the most commonly used additives in UPFs—emulsifiers. She investigates how they work, what they do, their history, associated health concerns, and their potential future developments.Featuring: Nicola Lando and Ross Brown from the online specialty cooking supplies company Sous Chef; Tim Spector, professor of epidemiology at King’s College London and co-founder of the personalized health app Zoe; food historian Annie Gray; John Ruff, Chief Science Advisor at the Institute of Food Technologists; Professor Barry Smith at the University of London’s Centre for the Study of the Senses; Professor Anwesha Sarkar, an expert in colloids and surfaces at Leeds University’s School of Food Science and Nutrition; and Dr. Benoit Chassaing, a research director at The Institut Pasteur in Paris, who studies microbiota and the health impacts of certain emulsifiers.Presented by Jaega Wise Produced in Bristol for BBC Audio by Natalie Donovan