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.