Bella Davis has struggled with body dissatisfaction since she was eight years old. “I grew up thinking having a soft body was wrong,” says the now 29-year-old from the Central Coast.

As a teenager, Davis was “always striving to be thinner”, “obsessed with tracking calories” and “terrified to date” or be intimate with anybody in case they commented on her body.

Even going to the beach with friends was fraught. “I’d wait for them to go into the ocean first, because I felt really insecure,” she says. “Some days I’d cancel and say I was sick.”

Cancelling plans and becoming fixated on changing your appearance or body are symptoms of body dissatisfaction, estimated to affect 4.1 million Australians, according to the Butterfly Foundation.

Body dissatisfaction is a leading risk factor in developing eating disorders and “can also lead to anxiety, depression, self-harm, lower self-esteem, substance use and smoking”, says the Butterfly Foundation’s head of prevention services, Helen Bird.

It can peak in summer as we tend to wear less clothing, and Australia’s outdoor culture increases the opportunities to compare yourself with others, she says. According to the Butterfly Foundation, between 2012 and 2023 the overall number of people experiencing eating disorders in Australia increased by 21%; studies have found body dissatisfaction can rise during the summer months.

For Alex Rodriguez, 27, a dietitian and fitness instructor in Brisbane who lived with anorexia in his teens, disordered eating and exercising “was very isolating”, he says. “There’s a lot of pressure around summer bodies being lean, having to show off visible muscularity, trying to be ‘better’ or ‘more disciplined’ than our mates.

“When I was experiencing pretty significant disordered eating and body dissatisfaction, I was just never present. Christmas, birthday parties, beach trips, camping trips – I was never fully present when others were having fun, relaxing, connecting, taking photos, making memories.”

Bird says people with body dissatisfaction report “significant disengagement from activities”, including going to the beach or pool, pursuing romantic relationships, shopping, giving an opinion and standing up for themselves.

Rodriguez says his brain was “always elsewhere”. He recalls feeling anxious during social events, preoccupied by what his body looked like, what he was or wasn’t eating, or about how those occasions were going to impact his rigid exercise schedule.

His recovery has “been about learning what are genuine health-oriented goals … and what were forms of self-punishment or self-destruction”, he says.

The festive season brings “a surge in societal messages like ‘summer body shred’ and ‘bikini body’ as well as messaging about ‘overindulgence’”, says Bird. The message that “thinner or more muscular bodies are healthier, more attractive or more successful remains deeply ingrained”.

Bird says while there is limited research comparing global rates of body dissatisfaction, “we do know that these factors can make it difficult for many people in Australia to accept their body as is”.

As gyms, weight-loss drugs and food companies try to sell quick fixes for “healthier” bodies at this time of year, she says it’s important to remember “there is no such thing as a summer body. Every body that exists in summer is already a summer body.”

Davis, who is now a social media influencer for body positivity, says there are “a lot of people who profit off your insecurities”, but recent media coverage of celebrity weight loss has been particularly confronting. “It sends this message that you can’t live in a bigger body and be healthy, which is so untrue,” she says. “Bodies aren’t trends.”

Sophie Henderson-Smart, founder of Saint Somebody, which makes swimsuits for sizes 8 to 28, says, “Unfortunately in Australia, our beach culture is very fatphobic.”

She created her brand because she couldn’t find swimwear that fitted well, and says some of her customers have spent “20 years refusing to go to the beach, and certainly not in front of people they know”.

Being able to provide those women with swimwear they feel good in is “so special”, she says. “That feeling of bobbing around in the water is such an amazing feeling, it’s freedom.”

Feeling body confident took a lot of “unlearning”, says Davis. “It sounds so silly, but I can wear shorts and a singlet out of the house now and be happy.”

Davis still experiences body dissatisfaction on bad days. “But now I tell myself ‘I don’t have a bad body, I’m just having a bad body image day’,” she says. She is also careful about who she follows on social media, focusing on “people who are moving for joy, or to get stronger, not to change their body”.

Bird endorses this approach. “Unfollow or mute accounts and people that are leaving you feeling dissatisfied with your body,” she says. Instead, use social media to focus on “your hobbies, values and interests outside the realm of appearance”.

Before Rodriguez sets new health or fitness goals, he always checks in with himself about what they would contribute to his life. “I always ask myself: is this helping me be happier, more content, within myself?

“It’s not disordered to want to make improvements to the way we’re eating or to set a movement-related goal,” he says. “But it comes back to why we are doing these things and how it builds our life up, rather than … taking over our life.”

Most importantly, if you’re struggling with negative thoughts and feelings about body image, “reaching out for professional support as early as possible is key”, says Bird. “[It] can help stop body dissatisfaction becoming a lifelong struggle.”

• In Australia, the Butterfly Foundation is at 1800 33 4673. In the UK, Beat can be contacted on 0808-801-0677. In the US, help is available at nationaleatingdisorders.org or by calling ANAD’s eating disorders hotline at 800-375-7767. Other international helplines can be found at Eating Disorder Hope