Several viewers slammed Channel 5 show How To Lose a Stone in a Month on Thursday, describing the programme as out of touch.
Four food addicts were put on lose-weight-fast diets to try and drop as much weight as possible inside four weeks, in the series previously called How To Lose a Stone For Christmas.
They were all put on some of the world's most extreme weight-loss programmes - and had to stick to them.
Dr Amir Khan and Ruth Langsford helped them through it but one diet in particular caused a stir.
It saw one of the contestants told to survive on 800 calories a day - almost a fifth of what she was eating before.
One viewer tweeted: "@channel5_tv What kind of doctor advises to cut calories down to 800 a day on How to lose a stone for Christmas? Why are you pushing fad diets?"
Another said: "Just turned over to How To Lose A Stone and they've put someone on a liquid master cleanse + 800 cals on non liquid days. Bit irresponsible aint it? @channel5_tv".
The comments didn't get any better.
"Very reckless that a TV channel would allow this show to air, very worrying a 'doctor' is recommending poor dietary advice which isn't sustainable or beneficial - really frustrates me," one viewer reacted.
One to-the-point watcher added: "This is one of the worst programmes I have seen in a while!!"
Another said: "None of the diets are sustainable! Programmes like this are pointless and potentially dangerous."
Mirror Online has contacted Channel 5 for comment.
Despite the criticism, the four dieters all succeeded in their challenge to lose a stone inside a month.
Dr Amir and Ruth praised their dedication after slimming down inside four weeks.
They all vowed to keep "aspects" of their diet - but none of them said they will totally stick with it.
