Have you heard of ultra processed food? In 2010 a group of Brazilian scientists said we should be focusing less on the nutritional content of food, and more on the form of processing it undergoes. They created the Nova system, a way of categorising foods based on how processed they are. It identifies ultra processed foods as generally industrially manufactured, containing ingredients such as emulsifiers, stabilisers and other additives that would not be found in an average home kitchen. A growing body of scientific research suggests a link between this category of ultra processed foods and ill health, although there’s still some uncertainty around why this could be. In this programme we look at what ultra processed food is, how you spot it, and how practical it is to avoid it, should you wish to. Ruth Alexander speaks to listener Jen Sherman in California who is trying to reduce the amount of ultra processed food her family eats. Ruth also hears from one of the public health scientists behind the Nova classification, Jean-Claude Moubarac at the University of Montreal in Canada, and from Pierre Slamich, co-founder of the Open Food Facts app and website, a database of foods that can help you identify products that are ultra processed. Kate Halliwell, Chief Scientific Officer at the Food and Drink Federation in the UK, which represents manufacturers, says evidence of harm from ultra processed foods is not yet strong enough. If you’d like to contact the programme you can email thefoodchain@bbc.co.uk. Presented by Ruth Alexander. Produced by Beatrice Pickup. Additional reporting by Jane Chambers in Chile.