Secrets of Your Supermarket Shop - Season 4

Sian Williams, Stefan Gates and Nisha Katona return to lift the lid on production and sale of supermarket food, beginning with an investigation into snacks and treats. With the help of the Hill family, Sian asks whether it is possible to tell the difference between branded biscuits and the cheaper versions, while Stefan examines how junk food affects good gut bacteria.

The focus shifts to store cupboard ingredients, assessing how people can shop healthily and spend less when it comes to jars, cans and packets. Sian Williams lifts the lid on tinned food, which has seen sales soar since the start of the pandemic, and challenges the Wilkes-Malones to a blind taste-test to see whether they prefer the taste of canned food or the fresh equivalents. Stefan Gates visits London's last working windmill to discover how wholemeal flour is made and sorts the wheat from the chaff when it comes to the best flours to use for home cooking.

Sian Williams, Stefan Gates and Nisha Katona take a closer look at the fats and oils people regularly use when cooking. With the help of the Stickley family, Sian exposes the shocking amount of calories hidden in favourite salad dressings. And Stefan travels to Cornwall to visit Europe's only sustainable sardine fishery.