This Morning hosts Ruth Langsford and Eamonn Holmes spoke to Dr Michael Mosley on Wednesday's show ahead of his new Channel 4 documentary.
He claims he will help a group of people lose a stone in just three weeks with his diet, which only allows 800 calories a day.
This enraged plenty of viewers who thought this was irresponsible as men are supposed to eat around 2,500 calories a day, and women are supposed to eat around 2,000.
Assisted by his wife Dr Clare Bailey, Dr Michael puts the subjects through their paces over video calls, even telling them to pour sugary drinks down the sink in front of him. "How could you possibly be happy on 800 calories a day?" asked Eamonn. "It's pretty tough to begin with but what most people report is within
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