“Every vegan seems to have their own lightbulb moment when something clicked and they stopped eating animal products,” says Cambridge University archaeologist Dr Pía Spry-Marqués, who committed to a plant-only diet two years ago as she researched the history of pork.

“My son was born three years ago and I was nursing him. People looked at me funny for breastfeeding my child, and yet it was fine to drink lattes with cow’s milk, or eat chocolate spread,” she recalls to The Independent.

“I started thinking about how it’s weird to drink cow’s milk. I was writing the book and researching factory farming and pigs nursing piglets and it was all too much. I decided that I would go vegan the next day. And that was it.”

As Dr Spry-Marqués immersed herself in the history of pork - from the Paleolithic era to now- she learned about how pigs are relatively sensitive, social creatures which can express empathy. And about the extremities of industrial farming, where pigs are castrated without pain relief and kept in harsh, cramped conditions. And how the byproducts of this process end up in all sorts of items from paint brushes to medical gauze to yoghurts and bone china.

The archaeologist, who is based in Cambridge and originally from Spain, admits that before she began exploring the relationship between humans and pork for her book Pig/Pork: Archaeology, Zoology, Edibility, which is knowingly dotted with recipes including pig testicles served with a garlic sauce. She - like most of us - gave little thought about the provenance of the food she was eating.

“The only time I saw pigs were the dead piglets on display in Spanish butchers, or legs of ham in restaurants and bars. But you're so disengaged it doesn't shock you to see their pale soft skin on the counter. Now I think about it, it shocks me that it didn’t shock me before.

“I love Iberico ham. I love chorizo,” adds Dr Spry-Marqués. “But it’s just not worth it.”

Inspiring vegan food from Blissful Basil - In pictures Show all 10 1 /10 Inspiring vegan food from Blissful Basil - In pictures Inspiring vegan food from Blissful Basil - In pictures Inspiring vegan food from Blissful Basil - In pictures Blueberry Muffin Energy Bites Inspiring vegan food from Blissful Basil - In pictures Bright Morning Citrus Salad Inspiring vegan food from Blissful Basil - In pictures Carrot + Coriander Bisque Inspiring vegan food from Blissful Basil - In pictures Easy Does It Sunday Evening Chili Inspiring vegan food from Blissful Basil - In pictures Hellooo, World! Green Smoothie Inspiring vegan food from Blissful Basil - In pictures Inspiring vegan food from Blissful Basil - In pictures The Classic—Spicy Cauliflower Rice, Roasted Sweet Potato and Avocado Mash. Inspiring vegan food from Blissful Basil - In pictures Shaved Jicama Ceviche Salad with Avocado Inspiring vegan food from Blissful Basil - In pictures Seasonal Fruit Crisps Apple, Almond & Blackberry Sunflower

The existence of vegan wine was one the author's most startling discoveries, she says. "I was like ‘What?!’ Surely wine is vegan, it's just grapes.’ It’s not. Wine has animal-derived additives from eggs, fish bladders. And pig trypsin, which is banned in the EU but used in the US, is secreted by the pancreas and used to break down the proteins in wine and clarify the drink. It’s also found in beer," she says.

It quickly became clear to Dr Spry-Marqués that pork’s widespread use is an issue of supply and demand.

“The less meat we consume overall the less we have for byproducts used in some other way. We use every little part of the animal and if we’re going to be killing them we might as well. But if the consumption of meat decreases then we’ll need to find alternatives," she argues.

But Dr Spry-Marqués’ book isn’t simply a ‘veganiser’, written only to turn the stomachs of the biggest bacon butty fans. It also unpicks pork’s complicated cultural history. Pigs were first domesticated in what is now modern day Turkey around 9,000 years ago. Unlike other animals which were perused as prey and later captured and farmed - like chickens - pigs, or more accurately wild boards, were attracted to the waste food in human settlements and then farmed. "Look where they got themselves just for a few scraps of food,” says Dr Spry-Marqués.

“We now think of that region as pig free, but it is actually where it all began,” she adds. Completely independently, pigs were domesticated again in China a thousand years later, emphasising how our history with pork is vast and varied. Evidence suggests, for instance, that pigs were prohibited in Judaism and Islam in order to differentiate members of the religion. However, issues around safety and transporting the meat also likely played a part in it being vetoed, she adds. And during the time of the Spanish Inquisition, the authorities used ham to test whether a person had converted to Catholicism.

Pointing to carnism - a theory coined by social psychologist Melanie Joy - Dr Spry-Marqués argues that eating meat isn't something humans inherently do. Isn’t it strange that in the UK we happily scoff pulled pork but not pulled dog? When do we shudder at the idea of eating a horse steak, but salivate at the thought of a medium rare beef burger? Leviticus 11 in the Old Testament, which prohibits pork, also bans the eagle and “any kind of raven” and camels. The writer was piecing together how arbitrary what we eat is.

“We’re conditioned by an invisible belief system that encourages us to eat animals which is shared by all meat-eating cultures. If you think about the millions of different animals out there, we’ve only chosen a few that we class as edible. The others are seen as disgusting. Just imagine eating a rat.”

Two years on from devoting herself to veganism, Dr Spry-Marqués says she feels healthier but also like she had been cheated by how she used to consume food. So, perhaps she's not a “superhero vegan” and she has conflicts about ethically sourced quinoa and cashew nuts as much as meat. But she says she now gives her food a lot more thought.

“Even the tiniest step in one direction will make a difference," she argues. "The more mainstream it becomes you won't have to make that choice anymore, it’ll be the default.”