It's a Wednesday night and I'm out for dinner with a group of people. Some of them are friends but most I don’t know. When it comes to ordering, we start discussing what to get. Do we share? Do we get starters? Somewhere along the way I mention I’m a vegetarian so I can’t join in on sharing the meat options.

After we order and the waiter leaves, the guy sitting next to me turns and says, "So, why did you become a vegetarian?" It’s an innocent question, usually designed to start conversation, but more often than not it turns into a debate involving the whole table about the pros and cons of cutting out meat.

Since becoming a vegetarian in 2010 this same scene has played out in my life countless times. In different countries, cities, restaurants and bars. Face after face has seen mine fall, a look of resignation creeping over it as I lay down my fork and prepare to engage in a bottomless conversation that will rob my meal of its heat and my youthful vegetarian activism of any gusto it has left.

At 27, I’m spent.

So why the interest?

Most people love food. What we eat is a huge part of our everyday lives; it’s rich with tradition, history and nostalgia, and most importantly it brings people together.

Some of my earliest memories are of eating Christmas dinners at my grandmother’s house in New Zealand. Each year she would make a rich wet fruit dessert gleefully named "money pudding" stuffed full of small coins wrapped in tinfoil. The pudding itself tasted faintly like dishwashing liquid but that didn’t stop my brothers and me piling thick steaming wedges into bowls and retreating to our chairs to pull apart the sticky pieces for coins. After collecting our bounty and swallowing a few small spoonfuls of the goo, we would guiltily scrape the desecrated remains into our father’s bowl for him to finish up.

"When we see video footage of pigs rammed into cramped pens or chickens stuffed into tiny cages littered with poo and feathers, we are disgusted. But the connection between that and the chicken pad thai we are about to eat is not likely to be top-of-mind."

As adults, what we choose to eat also says a lot about who we are. People are quick to praise others for their healthy meal choices – seen as a sign of discipline – and look down on others for filling up on junk. But when someone choses to cut out meat, the food group central to most of the western world's meals, the response can be mixed.

Are you looking after yourself?

One of the most common things people bring up when I attempt to explain the reason why I became a vegetarian is health.

"I don't feel like you get all the nutrients you need from cutting out meat altogether," many say. "How do you get enough iron and protein?"

It's true that meat offers some nutritional benefits that are hard to substitute in a plant-based diet. Lean red meat is a good source of iron and protein, and vitamin B12 is only found in animal products. But what interests me more is the person in front of me who seems so worried about my health. No one seems to mind when I drink too much alcohol, have five coffees in a day or demolish a huge packet of chips in one sitting. But as soon as I hold up a spinach leaf as my primary source of iron, all hell breaks loose.

Making the break

People choose to become vegetarians for all sorts of reasons including animal rights, the environment or simply taste.

My own decision to make the change came about after years of half-hearted thoughts and one powerful course at university. I realised that my idea of myself as an "animal lover" was at odds with my diet and no amount of justification could get around that.

I loved the taste of meat and cutting it out was hard because that craving didn't disappear, but it was also easy because I knew why I was doing it; like appreciating someone is good-looking while knowing you can't flirt with them because you're in a happy relationship.

But cutting out meat didn't ease my conscience. Far from it. As soon as I began looking into animal industries I realised that animal products were everywhere and despite my new diet I was participating in horrible practices every day. Make-up, silk, eggs, milk and cheese all became sources of guilt. To be a truly ethical eater, I thought, would require me to eat nothing at all.

The modern hunter

Another point people often make is the circle of life. Humans have killed and eaten animals since the beginning of mankind – it's in our DNA.

But the days of the hunter-gatherer are long gone, and most people in the west, myself included, are completely divorced from the process of killing animals. When we see video footage of pigs rammed into cramped pens or chickens stuffed into tiny cages littered with poo and feathers, we are disgusted. But the connection between that and the chicken pad thai we are about to eat is not likely to be top of mind.

Hypocrisy exists in vegetarianism, too. People are often quick to point out my shoes are made from leather or my jumper from wool. They question how someone can be morally superior about food choices while also participating in industries that exploit animals for their byproducts. The answer – you can't, and most don't set out to be.

The righteous vegetarian

So where does all this hostility towards vegetarianism come from? For some people, it's the frustration of having to cater for them; for others it's the reasoning behind it. It doesn't help that some vegetarians take a righteous position. Take this quote from US actor Natalie Portman:

"Part of my reason for being vegetarian was because it practices respect and love for life all through the day, so three times a day, you make a decision to eat things that have not been killed."

Over the years I have reached the conclusion most people just don't want to feel judged, and even though becoming a vegetarian felt like a personal choice to me, the message behind stepping outside the status quo is that the status quo is bad, and that puts people on the defensive.

But it's quite the opposite. The realisation that you can choose what you do and don't eat gives you a greater appreciation for what people choose for themselves. I believe vegetarians think more about what they eat, because they are forced to, and often make healthier decisions. I also accept that I'm in a privileged position and some people don't have the luxury to choose what they eat. It would be silly to expect people in an impoverished country who happen to rely on meat for survival to adopt a vegetarian diet, for example.

An unwanted debate

So how to answer the question without sparking a tired debate? Over the years I have tried a number of different answers, from the early impassioned ones ("I didn't want to be involved in the killing of animals") to the older, more even-tempered ones ("I felt there were more reasons to become a vegetarian than not") to the downright lies ("I just stopped liking meat"). It seems that whatever I try, it's an issue people want to argue about.

After I became a vegetarian I envied friends who seemed confident about their stance on food while I was in the grip of panic about not doing enough and still contributing to animal industries.

Around that time I confided in a childhood friend who had been a vegetarian since she was 10 and didn't seem to have the same angst.

"Everyone has a line," she said.

"Whether your line is out here" – she extended her arm in front of her – "and you are a vegan...

"Or your line is here" – she pulled her arm closer to her chest – "and you are a vegetarian...

"Or here" – closer still – "and you eat only a small amount of organic meat…

"Everyone has to find their line. You just have to find yours and accept that."

It was good advice and I took it on board. My diet isn't perfect. I still eat eggs, milk and other dairy products. My bag is leather and sometimes when I smell chicken cooking I want to throw down what I'm doing and tear into it with my teeth.

But I've found my line and accept where others have set theirs.

Maybe that's what I'll say next time I'm asked.