Magazines and television are often blamed for portraying an ideal body image that causes people to question their looks and lose confidence in themselves. But what about the role social media plays in moulding attitudes to the way we look?
Kelsey Hibberd, from Southend, remembers her years at secondary school as being miserable. She intentionally kept her Facebook friends to a minimum because she knew they were the ones who wouldn't pick on her.
"I'd always been tall, and I was a bit podgy too," she says.
"No-one seemed to notice at primary school, but then in Year 7 everyone started pointing at me, noticing things, making me think I was ugly and not special."
She became increasingly conscious of even tiny things such as the shape of her eyebrows and size of her forehead.
"I would have been subject to much more abuse if I'd had more friends on social media," she says.
Kelsey describes the bullying she experienced between the ages of 11 and 16 as "absolutely awful".
"It was all about my body and how I looked," she says.
She changed her hair colour and stopped eating to try to fit in before she realised that "it was for other people to stop hating on me".
Now, at 20, Kelsey is running a mentoring programme called Loud Education, which goes into schools to talk to pupils and train teachers on how to deal with body confidence issues. It also provides advice on any lesbian, gay, bisexual, and transgender issues pupils might have.
As a result, she is well aware of the power of social media. Teenagers can have thousands of "friends" online and that can leave them exposed, she says.
"You put forward your best self, and that can be a bit dangerous, because you naturally compare yourself to others," she says.
Among teenagers, Facebook, Twitter, Instagram and a number of other messaging apps, such as WhatsApp, are their main means of communicating with each other and the world.
In 2013, two-thirds of teenagers had signed up to the Facebook app, where images are posted and shared millions of times a day.
Never have they known so much about their friends' lives and the way they look.
In 2012, MPs recommended that all schoolchildren should take part in compulsory body image and self-esteem lessons.
An inquiry by the All-Party Parliamentary Group on Body Image heard evidence that girls as young as five were worrying about their size and their appearance.
Adults were not immune from these negative attitudes either, with about 60% of the public feeling ashamed of the way they looked.
The MPs' report said pressure to look good had pushed up cosmetic surgery rates by nearly 20% since 2008.
MP Caroline Nokes was a member of the parliamentary group which, along with a number of charities, businesses and public bodies, is launching a campaign to change attitudes to body image, called Be Real: Body Confidence for Everyone.
She has visited schools and talked to 12- and 13-year-olds about how easily images in the media can be altered, enhanced and improved to create something far from realistic.
They understand, she says, because they go through the same process when they post images on social media sites.
"I ask them to shut their eyes and put their hand up if they have ever enhanced an image on Facebook," Ms Nokes says.
They usually all put up their hands. she says. One girl said every image she uploaded had been altered.
Most cameras in smart phones have built-in filters and a range of effects that can be used to enhance even the most embarrassing selfies.
Social media has a huge effect on young people's body confidence, she explains, because it cannot be ignored.
"They can make decisions not to look at magazines and TV, but social media networks are the primary way they communicate and their main channel to the outside world," she says.
"But they are seeing the world through a filter, and that's not healthy."
She wants to make teenagers feel better about themselves by making them wary of an appearance-based world.
"It's really important we try to instil confidence that they can be who they are," she says.
Her aim is to educate young people, to make them more cynical about the images they see and admire, and to work with retailers and businesses to encourage them to be more responsible in their advertising.
Dr Phillippa Diedrichs, senior research fellow at the University of West of England's Centre for Appearance Research, says research backs up the link between social media and body image concerns.
"The more time spent on Facebook, the more likely people are to self-objectify themselves," she says.
She explains there is a tendency to seek out negative social interactions in these forums, and to ask people to comment on how you look, which can lead to body image anxieties.
People using social media sites also tend to cultivate a persona, and even friends and a peer group, she adds.
In her view, the answer to body anxiety is to showcase a more diverse range of bodies in the media because there is not just one way to be healthy or one ideal look.
Kelsey agrees. She rebuilt her confidence by volunteering with the YMCA when she 15. When she went to college, she started to rediscover who she was and feel comfortable about her body again.
Now she has plans to go into advertising.
"I want to get in there and change the norm, change perceptions for the better. People are drip fed so why not drip feed them with positive things," she says.