The range of fats and oils available to us is growing but the advice has changed dramatically. Sheila Dillon looks to cut through the latest thinking to help gain clarity of which we should be using when.

She's joined in the studio by Dr Michael Mosley whose recent investigation looked into how the composition of saturated and polyunsaturated fats changed when heated with food and resulted in the production of dangerous aldehydes. Sheila finds out what response there has been since the programme and how he's changed his own cooking and buying habits but what questions should we be asking when we eat out?

Over the past decades animal fats have lost out in popularity and newer products like coconut oil have risen in prominence. Yet a butcher from Clonmel in Tipperary has seen his dripping crowned 'supreme champion' in the Great Taste awards - could this signify a change of thinking on what was once classed 'unhealthy fats'. Meanwhile in parts of Italy a new disease is threatening olive trees.

N.B. In this programme, mustard oil is used. Due to the high levels of the allergen erucic acid present in mustard oil, EU regulations state that the oil must be marked for 'external use only'. However, it continues to be widely used in Indian cooking and is often recommended by chefs to create authentic dishes.