Sian Williams, Stefan Gates and Nisha Katona investigate how the food we eat can affect our wellbeing. Stefan visits the London Sleep Centre to explore how what we eat and drink can drastically affect the quality of our sleep, and undertakes an experiment to see how excessive amounts of caffeine, alcohol and takeaways alter his sleep patterns. Meanwhile, Sian takes a look at changes to portion sizes over the past three decades, and Nisha meets dietitian Hannah Whittaker to discuss superfoods.

British shoppers buy 95 per cent of their food from just 10 supermarket chains. But how much do they really know about how this produce is grown, made and sold? Sian Williams and Stefan Gates present this investigative documentary in which they lift the lid on the secrets that the supermarkets do not want their customers to know.