Instagram has announced stricter measures on posts related to weight loss products and cosmetic surgery.
Some posts will be hidden from under 18s while others promoting "miraculous" weight loss products will be removed.
There have been increasing concerns over the impact promoting diet products can have on young people.
Actor and body positivity activist Jameela Jamil said the move was a "huge win" in the fight against the diet and detox industry.
Unrealistic "get thin quick" promotions will be taken down and young people will be restricted from viewing some posts related to dieting and cosmetic surgery if they have an incentive to buy.
The changes will also apply to Facebook, which owns Instagram.
Emma Collins, Instagram's public policy manager said: "We want Instagram to be a positive place for everyone that uses it and this policy is part of our ongoing work to reduce the pressure that people can sometimes feel as a result of social media."
Advice had been sought from experts in the field of social media policy, she added.
There has been increasing concern over the effect the cosmetic and diet industry is having on people through the promotion of unrealistic goals.
In February, the medical director of National Health Service England, Stephen Powis, called for a ban on celebrity-endorsed social media ads promoting weight loss aids, stating that products were having a damaging effect on the physical and mental health of young people.
Ms Jamil, who founded the I Weigh movement as a reaction against content promoting weight loss products and unhealthy lifestyles, welcomed the changes.
"Facebook and Instagram taking a stand to protect the physical and mental health of people online sends an important message out to the world," she said.
"I'm thrilled to have been able to work towards this with them, alongside a host of other experts who shed light on the danger of these products."
- BBC