Imagine if the food you eat could 'clean' your body and make you feel well. Dr Giles Yeo investigates the latest diet craze and social media sensation - clean eating.

In a television first, Giles cooks with Ella Mills, the Instagram entrepreneur behind Deliciously Ella, one of the most popular brands associated with clean eating, and examines how far her plant-based cooking is based on science. She tells him clean has lost its way: "Clean now implies dirty and that's negative. I haven't used it, but as far as I understood it when I first read the term, it meant natural, kind of unprocessed, and now it doesn't mean that at all. It means diet, it means fad".

Giles sifts through the claims of the Hemsley sisters, who advocate not just gluten-free but grain-free cooking, and Natasha Corrett, who popularises alkaline eating through her Honestly Healthy brand. In America, Giles reveals the key alternative health figures whose food philosophies are influencing the new gurus of clean. He discovers that when it comes to their promises about food and our health, all is not always what it appears to be. Inside a Californian ranch where cancer patients have been treated with alkaline food, Giles sees for himself what can happen when pseudoscience is taken to a shocking extreme.

Horizon Season 56 Episodes...

• s56e01 - Clean Eating - The Dirty Truth
• s56e02 - Hair Care Secrets
• s56e03 - ADHD and Me with Rory Bremner
• s56e04 - Why Did I Go Mad?
• s56e05 - Strange Signals From Outer Space!
• s56e06 - Space Volcanoes
• s56e07 - Antarctica - Ice Station Rescue
• s56e08 - Cyber Attack - The Day the NHS Stopped
• s56e09 - 10 Things You Need to Know About the Future
• s56e10 - Dawn of the Driverless Car
• s56e11 - Dippy and the Whale
• s56e12 - What Makes a Psychopath?
• s56e13 - Mars - A Traveller's Guide
• s56e14 - Goodbye Cassini - Hello Saturn
• s56e15 - Being Transgender

Horizon Show Summary

Horizon is BBC Two's flagship 50-minute science documentary series.

Recognised as the world leader in its field, it regularly wins a sweep of international science, medical and environmental film accolades, and has recently won the Royal Television Society Award and the Prix Italia.

In 2002, the British Academy of Film & Television Arts presented Horizon with the BAFTA Television Award for Best Factual Series or Strand.

In 2003 it won the prestigious Images et Science award for best medical documentary and the Carl von Linne Award at the Living Europe film festival in Sweden. That year, a Horizon co-production with WGBH Boston won the Emmy for best documentary.

In September 2014 it celebrated its 50th anniversary and it continues to enjoy outstanding critical acclaim.