As a 115kg (18st) woman who refuses to diet, unapologetically wears short shorts and eats tiramisu, I have experienced and witnessed a lot of fatphobia. This is a form of bigotry that equates fatness with ugliness, inferiority and immorality. In my new book You Have the Right to Remain Fat, I talk a lot about how being fat has shaped my life, how fatphobia has multiple dimensions and how it does not just move outward – from us to others. It moves inward – from our culture to ourselves.

Researchers who study stigma have found it often leads to depression and anxiety, as well as decreased access to employment, friendship, romantic opportunities and a sense that one is not welcome in the wider culture. Fatphobia has manifested itself in unexpected ways in my own life. I’ve found, for instance, that men often approach me with an interest in starting a private sexual relationship but not a public romance, and that it has been harder to find jobs with opportunities for promotion because employers associate fatness with laziness. I argue for the right of every person – regardless of their size – to live a life free from discrimination.

Here are 10 of the most common instances of fatphobia that personally affect me and many others – with some advice about how to combat them.

1. ‘Wow, haven’t you lost weight!’

I remember going to the family doctor when I was 11, having spent the summer starving myself. I’d only eaten toast and lettuce and exercised two to three hours a day in the hope I could spend my final year of primary school free from constant teasing. When the doctor saw me he did not ask how a child had lost weight so rapidly or express alarm that I might be sick. He congratulated me, told me to keep up the good work and said if I lost more weight I might be able to date one of his sons. One woman I worked with told me she had developed a drug habit in order to maintain her low weight, and had never received more compliments than at the height of her addiction. Weight loss is always considered positive, no matter how it’s achieved. “You’ve lost weight!” seems innocuous, but it actually creates an uncomfortable sense that people are surveilling and judging your body.

Make it a rule not to use language that focuses on your own or others’ weight. We have no idea what someone is going through, whether they are dealing with body shame or trying to heal from an eating disorder. When we stop using this kind of language altogether, we create an environment in which people of all sizes can coexist without a sense of weight surveillance.

2. Selfies taken from above

The religious avoidance of the double chin in selfies – with the camera always held 20cms above the photographer’s head, with the face tilted just so – sends a constant message about who and what is worth documenting.

Try documenting yourself at different angles. Remember you are photographing a special emotion or an important moment, and that you are trying to capture a two-dimensional image of a complex person.

3. Tiny seats in restaurants

Many fat people have anxiety about seating at restaurants. Will there be booths where the space between the table and the seat is fixed? Will the chairs be wobbly little metal ones held up by the furniture equivalent of pipe cleaners? This anxiety leads to many fat people opting out of social dining situations.

The restrictive size of seating – and this applies strongly to desks in classrooms too – is an example of what’s called structural fatphobia. It is not a person hurting another person directly. It is what happens when we create structures based on presumptions about which bodies belong in which places.

If you’re going for dinner with a fat friend, check images of the restaurant’s interior to make sure there are sturdy chairs without armrests, and non-stationary tables and chairs if cramped booths are the main seating option.

4. Romantic discrimination

We chalk up a lot of our romantic decisions to evolutionary biology, but the truth is our partner choice is highly influenced by social expectations and ideals. If we lived in Mauritania, for example, where fatness is the beauty ideal, we would have no difficulty finding “biological” rationalisation for that attraction. We are taught who is beautiful, and get social cues about who to avoid choosing as a partner.

It is useful to remember that our first reaction to another person is often a result of how we have been trained, socially, to react. We can take a moment to ask ourselves whether making romantic decisions in this way is getting us what we truly want. I have found that in romance I really want a sense of safety, shared values and overall chemistry. But we are not trained to seek out those qualities. We are trained to seek out people who adhere to one-dimensional, culturally set standards. Attraction is wonderfully complex and we miss out when we only experience it along one axis – how someone measures up to beauty standards.

5. Aggression on public transport and planes

Most instances of overt fat hate happen to me on public transport. I avoid busier times on the train (peak commuter hours and when teenagers get out of school) because I have found I am much more likely to be accosted verbally in a packed carriage. Once, a group of teenagers sat in front of me and began taking selfies. I watched them huddle together and start laughing. One of them tipped the phone and I saw that they were laughing at a zoomed-in image of my face. Another time, I asked a thin woman who was lying across three seats on a train platform if I could sit down; she called me a fat bitch. In this second instance, another thin woman stood up for me and proceeded to tell her off. I will always be grateful. It is important to interrupt instances of bigotry because we do not want to live in a world where anyone can be harassed because of who they are or what they look like.

6. Professional and formalwear do not come in plus size

A fat activist once said clothing was the alphabet we used to express ourselves – and fat people have fewer letters. When applying for jobs, I found it impossible to find well-made professional clothing that I liked in my size. This decreased my confidence. I could see my smaller colleagues were better dressed and it made me question whether I belonged. A friend of mine almost relapsed into her eating disorder when she was preparing to get married; she had so much difficulty finding a dress that she questioned whether she deserved to be a bride. Business suits, tuxes and wedding gowns are harder to come by in larger sizes. This sends a message about who gets to participate in important cultural moments and who belongs in the business world.

7. Fashion double standards

Beyond formalwear, fashion creates other problems. Thin people and fat people can be wearing the same item of clothing and be perceived differently. A thin person wearing yoga pants may be presumed to be heading to the gym, while a fat person may be perceived as sloppy. A thin person in a tank top is not noteworthy; a fat person in a tank top is scandalous or brave. In a 2017 Allure article, the plus-size model Ashley Graham declared she was tired of being called brave for wearing a bathing suit. In 2016, a woman from Florida called Kelley Markland came home to a note from a stranger that declared: “Women who weigh 300 pounds should not wear yoga pants.”

The solution to this one is simple: we all need to wear what we want. People who feel anxious about what other people are wearing should interrogate their beliefs and stop acting on their bigotry.

8. Fear of being seen in public with fat people

Many people, fat and thin, avoid being friends with or dating fat people for fear of public criticism. I once met someone who quite literally worshipped my body, but when it was time to take our casual hangouts into the public sphere he told me he did not have the balls to be seen with me. I ended the relationship, and have since vetted my dates in order to avoid partners like him.

The journal Appetite published the “fat suit study” in 2014. This involved a professional actor going out in public on different occasions, with and without a fat suit, and serving herself either a small amount of pasta and a large amount of salad or a large amount of pasta and a small amount of salad. It was found that participants served and ate a larger amount of pasta when she was wearing the prosthesis than when she was not, and it was therefore posited that being near a fat person inspires people to eat more. This kind of inquiry legitimises the sense that proximity to fatness bears the threat of contamination.

It is an unfortunate reality that we are taught to avoid being seen with people who differ from the norm – whether because of body size, gender, disability or even fashion. We all lose when we live like this. It is important for fat people to recognise that we are worthy and deserve to develop boundaries when it comes to the kind of behaviour we will accept. And it is important for thin people who are afraid of being seen with fat people to interrogate their fear and ask themselves what they lose when they deny someone else’s humanity.

9. Unsolicited weight-loss advice

Just the other day, a complete stranger came up to me while I was sipping a latte in public and told me to avoid pork so I could reduce my weight. This behaviour is jarring – and more often comes from well-meaning people we know. Though I am no longer friends with people who offer me weight-loss advice, there were many years in which I found myself on the receiving end of incessant suggestions from my grandmother, my extended family at holiday parties, the woman who sold me coffee every day, teachers, nurses and doctors. Trust me. Fat people have tried every kind of diet; this kind of advice only makes us feel alienated.

10. Medical discrimination

Often doctors refuse to treat fat people properly, insisting that if we lose weight the issue – whatever it is – will simply go away. I have gone to the doctor with a sore throat and left with a prescription for weight loss. When I edited an anthology in 2012, a woman submitted a story about going to her doctor with suspicions she might have a serious uterine problem – doctors diagnosed her on sight as having polycystic ovary syndrome without examining her. Three years later she found out she had cancer, which could have been treated much earlier if her health had been taken seriously. I met a woman who was pressured to get weight loss surgery as a teenager and now, because of the way that kind of surgery can affect bones and teeth, she deals with huge dental bills. Medical discrimination leads to delayed diagnosis and treatment, and poorer health in the long run. It has to stop, for everyone’s sake.

• Virgie Tovar’s You Have the Right to Remain Fat is published by Melville House at £7.99. To order a copy for £6.79 go to guardianbookshop.com or call 0330 333 6846.