The before-and-after photos that prove weight gain isn't something to fear.

It was 2012 and Hannah Foster was at her lightest.

She was on a trip to Spain and for one of the first times, she let someone take a picture of her wearing a bikini.

Five years later, the Californian native has gained back some of the weight. But, she says, she’s way happier than she was back in 2012.

Sharing a side-by-side image of the two photographs on her Instagram account, Hannah said she wants people to realise that “transformations aren’t always what they seem”.

Transformations aren’t always what they seem. Pic on the right is after losing almost 100 pounds in 2012. It was one of the first times I had ever allowed anyone to take a picture of me in a bikini (and only because it was my first time swimming in the ocean). The girl on the left hated herself vastly more than the girl on the right, even though she weighed 30 pounds less than right-girl. She was in a nasty relationship, living abroad and lonely, and despite losing weight STILL HATED HER BODY. Losing weight won’t make you love yourself. . . Pic on the right is after 25 years of realizing that losing 5 pounds won’t make me a better person, it won’t make me like myself, and most importantly it won’t make me happy. I go to the gym, I eat healthy, but it’s not for weight loss; it’s because I only get one body and I want to use it as long as possible. Eating 800 calories a day isn’t taking care of your body, even if it makes you skinny. (Eating that little is part of what made gain weight, I was starving my body.) #barebutbold . . #bopo #bopowarrior #bodypositive #effyourbeautystandards #embracethesquish #selflove #selfloveclub #loveyourbody #loveyourself #curvy #plussize #plusisequal #allworthy #allbodiesaregoodbodies #nowrongway #nowrongwaytobeawoman #nomakeup #nophotoshop #sacigers #curvygirl #transformation #tbt #throwback

A post shared by Hannah (@lavidahannah) on May 4, 2017 at 10:59am PDT

“The girl on the left hated herself vastly more than the girl on the right, even though she weighed less than right-girl,” she wrote.

“She was in a nasty relationship, living abroad and lonely, and despite losing weight STILL HATED HER BODY.

“Losing weight won’t make you love yourself.”

Monday motivation to continue my affirmations of self love and keep focusing on a balanced and kind life. ✌???? #motivationmonday #motivation #bodypositive #bopo #bopowarrior #barebutbold #allworthy #allbodiesaregoodbodies #curvy #curvygirl #plussize #plussizefashion #fatshion #selflove #selfloveclub #loveyourself #loveyourbody #nomakeup #nowrongway #nowrongwaytobeawoman #effyourbeautystandards #embracethesquish #aeriereal ✌???? @nonairbrushedme @nowrongwaymovement @aerie

A post shared by Hannah (@lavidahannah) on Apr 24, 2017 at 7:50pm PDT

The picture on the right, taken on a recent trip to Hawaii, is symbolic of Hannah’s realisation that “losing five pounds won’t make me a better person”.

“It won’t make me like myself, and most importantly it won’t make me happy. I go to the gym, I eat healthy, but it’s not for weight loss; it’s because I only get one body and I want to use it as long as possible.

“Eating 800 calories a day isn’t taking care of your body, even if it makes you skinny. (Eating that little is part of what made gain weight, I was starving my body.)”

Not bad for a Wednesday ???? I’m so happy to be comfortable enough to actually enjoy the beach instead of hiding behind a sundress or quickly covering up with shorts. Thank you #bopo! . . #instagood #goodvibesonly #goodvibes #goodlife #bopowarrior #body4me #bodypositive #allworthy #allbodiesaregoodbodies #effyourbeautystandards #hawaii #maui #instatravel #loveyourself #loveyourbody #selflove #selfloveclub #curvy #curvygirl #fatshion #plussize #plussizefashion #nowrongway #nowrongwaytobeawoman #barebutbold #imjustnotthatsize . . @nowrongwaymovement @plussizestylewatch @strutbymic @styleandcurve @allisonkimmey @allstarcurves @effyourbeautystandards @mybodysmiles @imjustnotthatsize

A post shared by Hannah (@lavidahannah) on Apr 19, 2017 at 2:02pm PDT

Speaking to Yahoo Beauty about the two images, which have been shared around the globe since Hannah posted them, the 25-year-old said they perfectly illustrate the lie that being thinner means being happier.

“This photo is the perfect illustration of looking ‘thinner’, but truly still disliking myself for a whole host of reasons, body-image-related and not,” she said.

“After losing weight, my body image struggles seemed to pause for about four months, but that just let other image and personal issues come out that had been overshadowed by primarily hating my body.”

LISTEN: Is it ever OK to comment on someone’s weight?

For years, Hannah said, she had convinced herself that losing a little more weight, exercise a little more, she would be much happier.

“The turning point for me was talking with someone about disliking my body and she said, ‘If you talked to another person the way you talked to yourself, you would seem like the most horrible, nasty person. You’re not a horrible, nasty person, so why do you treat yourself that way?’

“This just blew my mind,” Hannah said.

Now, Hannah wants to use her voice to let other women know the ‘fantasy’ of being thin and happy is not realistic.

I’m going to Hawaii for the first time next week. I used to LOATHE vacations to sunny places because I hated my body so much and wanted to cover up as much as possible. I would almost never wear a swimsuit in public unless I wrapped up in a towel or sundress. I actually get to be excited for a trip to a tropical destination for once; it’s a such an amazing new feeling! ???? . .p.s. I used a filter on this because the original pic was so overexposed you almost couldn’t see my skin haha . @allisonkimmey @nonairbrushedme @effyourbeautystandards @styleandcurve @plussizestylewatch #effyourbeautystandards #allworthy #bikini #body #bodypositive #bopo #bopowarrior #nowrongwaytobeawoman #nowrongway #allworthy #allbodiesaregoodbodies #selflove #loveyourself #hawaii #travel #wanderlust #loveyourbody #forever21 #plussize #cellulite #plussizefashion #fatshion #curvy #curves #curvygirl #curvyfashion #nomakeup @garret_43 @allstarcurves

A post shared by Hannah (@lavidahannah) on Apr 12, 2017 at 3:45pm PDT

“If you can just get there then you will be happy and perfect and your whole life will be better. This point does not exist,” she said.

“I know a lot of women don’t love themselves, because if they did, we wouldn’t have women’s magazines telling us how to improve our bodies and they wouldn’t make any money.

“We wouldn’t need to talk about body image or self-love if there weren’t so many women who looked at themselves and compared themselves to others.”