PREVIEW: 21 Day Body Turnaround With Michael Mosley, Channel 4

Michael Mosley asks five volunteers to put their lives in his hands as he attempts to turn their health around in just 21 days.

Using the latest research, Michael transforms what they eat, and introduces a programme of intermittent fasting. He works with GP and fitness trainer Dr Folusha Oluwajana to radically increase their activity levels, including high intensity exercise. And he explores a host of other ways for the volunteers to work on their aerobic fitness and general well-being - with everything from algae-topped smoothies to cold water swimming and balancing on one leg.

Can Mosley cut the volunteers' risk of disease, shave years off their aerobic age, and also transform their overall health in just 21 days? In the first episode, Michael runs a raft of tests on the volunteers to assess their health, and examines what they eat. Michael investigates their digestive health and starts them out on a new training plan.

The whole series will be available to stream or download for free, on All 4, following transmission of this episode on Thursday 27 May.