A government minister has written to magazine editors asking them not to promote post-Christmas "miracle" diets because they pose a "health risk".
Equalities minister Jo Swinson wrote an open letter asking magazines to "shed the fad diets and fitness myths" in their January editions.
She suggested they "celebrate the beauty of diversity in body shape, skin colour, size and age" instead.
Ms Swinson is one of the co-founders of the Campaign for Body Confidence.
The letter was sent to magazines aimed at women and men, as well as health, celebrity and gossip publications.
Ms Swinson wrote: "I am sure that you want to promote a healthy lifestyle for your readers but at this time of year in particular far too much of magazine coverage tends to focus on irresponsible, short-term solutions and encourages readers to jump on fad diet bandwagons.
"As editors you owe more to your readers than the reckless promotion of unhealthy solutions to losing weight.
"If your aim is to give practical, sensible advice about losing weight - and not how to drop a stone in five days - you should encourage reasonable expectations, instead of dangerous ones, along with exercise and healthy eating."
She later told the BBC she was opposed to "any diet that is encouraging you to lose weight at a miracle speed, which is an unhealthy speed, or cutting out food groups, or skipping meals.
"Any of these kind of fad diets actually can have negative health consequences, and most diets don't even work anyway."
Jane Johnson, former editor of Closer and The Sun's Fabulous magazine, told the BBC that magazines do care about their readers and are very careful about the advice they give.
"Most magazines now are very much about holistic wellbeing.
"I don't think many magazines nowadays do the whole miracle fad diet thing. It's seen as very irresponsible and they want to make sure their readers stay with them, trust them and are loyal to them.
"Readers do go to them for advice, rather than the government," Ms Johnson said.
Ms Swinson did concede that magazine editors would have decided their January content some time ago, making any late change to their content difficult, but added: "I hope that the editors will recognise that this is something their readers really do worry about.
"It's something which affects people of all ages and in particular, many parents are worried about the message that this sends to their children."