Certain posts will be hidden from users under age 18 while others will be removed from Instagram as well as parent company's platform Facebook, Instagram's public policy manager Emma Collins said in a statement on Wednesday.
"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," Collins was quoted as saying in a report on cbsnews.com.
Social media users including actress Jameela Jamil have long been criticizing influencers like Kim and Khloe Kardashian and Kylie Jenner for promoting fat-loss products.
"If celebs and influencers were actually honest with us about some of these diet/detox products..." Jamil had tweeted in November last year which went viral.
Instagram will remove posts entirely if it "makes a miraculous claim about certain diet or weight loss products, and is linked to a commercial offer such as a discount code".
The updated policy is part of Instagram's work to "reduce the pressure that people can sometimes feel as a result of social media,a said Collins.
Earlier, in an interview with the London Evening Standard, Collins said Instagram worked with external experts to make this change without ruining the spirit of the platform.
"We want Instagram to be a positive place for everyone," she said.
Several studies in the past have suggested that Instagram may be a contributing factor to eating disorders and depression among teenagers.
A recent study published in the journal Pediatrics showed that children who view unhealthy snack images on social media platforms like Instagram are likely to consume more calories from unhealthy snacks.
"The results are supported by celebrity endorsement data, which show unhealthy food endorsements increase children's unhealthy food intake, but healthy food endorsements have little or no effect on healthy food intake," said researcher Anna Coate from the University of Liverpool in Britain.
The study was conducted with the aim of examining the effect of social media marketing of snack foods (healthy and unhealthy), via vloggers' Instagram pages, on children's snack intake.
Children in the group that viewed the unhealthy snack images consumed 32 per cent more calories from unhealthy snacks specifically and 26 per cent more calories in total from healthy and unhealthy snacks compared with children who saw the non-food images, the findings showed.
The results suggest that the marketing of unhealthy foods, via vloggers' Instagram pages, increases children's immediate energy intake.
( With inputs from IANS )