Table 2.

Themes, sub-themes, and representative quotes derived from the interviews conducted in 12 study participants

Theme	Sub-theme	Representative quote
1. Personal factors and cultural beliefs	1.1 Ethics and animal rights	“And now I care less about the health, the reason for myself, and it’s more for ethical reasons.” (ID 05) “And then I started volunteering in an animal sanctuary, and I had, like a closer relationship to like cows and pigs and things like that. So I just felt like I was like disrespectful to animals.” (ID 12) “The initial change was for sort of moral, compassionate reasons.” (ID 07) “I know deep down in my heart, that it’s not right what we’re doing to other creatures. I also think for most vegans. That’s the way to sustain it is just having it as a bedrock value that it’s not right.” (ID 04) “The most important reason I consume the diet is for ethical reasons.” (ID 08)
	1.2 Health effects	“I did it mostly for my health. A number of years ago, when I got ulcerative colitis, I was looking into different diets, and I realized that a plant-based diet, if done properly, could make the inflammation go down. And so I started on a plant-based diet. And it worked!” (ID 01) “I was told I had like a dairy sensitivity, so I removed it from my diet and then I gradually kind of went plant-based after that.” (ID 05) “I’ve been anemic before, which is just common among reproductive-age women [who] menstruate. So, I guess feeling like, maybe, you know, there’s no way to probably overcome that from a dietary perspective…maybe not getting all the nutrients I could get from, you know, non-plant-based sources.” (ID 06)
	1.3 Culture and religion	“Cultural reason for me, as an Indian, the South Indian vegetarian, I mean, I never grew up with meat in my house…I can say my parents, to an extent, disapprove of me not eating a plant-based diet for religious and cultural reasons, but as I’ve gotten older, I also care less about what my parents say, so it doesn’t really matter. It’s kind of what I want.” (ID 02) “I’m vegetarian, and I have been since I was born because my family just raised me that way.” (ID 03)
	1.4 Environment and climate change	“And for the environmental health as already proven. Then that’s why I’ve stuck with it… For like water use is a very big thing because maintaining farms and places where meat is processed uses a ton a ton a ton of water.” (ID 03) “Back, you know, years ago when I started, maybe… it’s a little bit more now because of the seeming urgency of climate change.” (ID 11)
	1.5 Weight management	“I feel like it’s easier to keep my weight down. You know, even though I’m now post-menopausal, do gain a little weight now and then. And I feel like it’s a good way just to, to stay healthy.” (ID 04) “I feel like adhering to a plant-based diet does make it easier to have a long-term weight management goal if I want to stay as fit, partially because of the satiety of plant-based foods. Especially if I truly have a portion of my meal that’s like whole vegetables and whole grains, so there’s only so much you can eat, plus the fiber content also makes it difficult to digest everything I’m eating.” (ID 02)
2. Social influences	2.1 Influence from loved ones	“For the approving side, I would definitely say my family. And I think that’s just because they also follow a plant-based diet. It also aligns with, you know, cultural values that they held when they first raised me that way. So in that way they’re pretty approving. My significant other also eats a plant-based diet.” (ID 03) “I’m probably a little less plant-based now, just because my partner was vegan for most of our relationship, and he has just recently decided he doesn’t want to be a strictly vegan.” (ID 06)
	2.2 Influence from peers	“One of my friends would not be happy with me if I walked to an Indian buffet and just get the dessert and like did not touch the raw vegetables. So, like dessert and rice, and really just fatty curry that they have, you know. ‘But you have to eat your vegetables’… At first, it’s a joke, but that’s the real pressure.” (ID 02) “I grew up in a very conservative town…I had a friend who was vegan in high school, and I saw the way people treated her, including myself - like I’ll be totally honest, like just the judgment that she experienced, and I was like ‘I could never do that,’ just seeing the way she was treated for it. So that’s just- that was the norm to me, but I don’t experience it now.” (ID 09) “Also, the social aspect. You know, there’s sort of a stigma around veganism that I didn’t really want to be a part of…I didn’t wanna experience like the bullying that comes with being a vegan.” (ID 09)
	2.3 Influence from authoritative figures	“[One] person I need to add to that list is my primary care doc. I’ve only had a handful conversations for my primary care. Remember the whole message for me is saying, should consider eating healthier if you want to gain weight. There’re ways you can do that, without just eating sugar. Here’s a list of plant-based foods that are higher in like good fats and higher calories by definition.” (ID 02) “I’m influenced by opinions of experts in the field… one major one is like, who’s done major nutrition research is Walter Willett…There was one paper that came out on eggs that he did, and my parents ended up consuming a lot fewer eggs.” (ID 10)
	2.4 Influence from books, classes, and social media	“I did read books about like environmental impact. So, I mean, that just kind of like strengthened my resolve.” (ID 12) “I took an interesting class like a few years ago. I’ve been eating more vegetables since then.” (ID 12) “I think on social media, I am a lot and influenced positively, like I follow a lot of people like, let’s say, just like on Instagram, or read a bunch of articles about people who also consume plant-based [diets].” (ID 03)
3. Consumption of plant-based diets at home and away from home	3.1 Limited options when eating out and traveling	“The fact that restaurants may give you one choice, or you’re basically stuck with salad.” (ID 01) “Availability - I think one concern I have is where I go next… will I live in a place that has enough around me for me to consume? Like enough restaurants that cater to plant-based diets.” (ID 03) “I feel that I don’t have amazing access to eating a lot of the cultural foods that I did growing up…there are just not vegan versions of them, and if there are, like, they’re not nearly as accessible.” (ID 08) “Sometimes when traveling it can be hard like, I think a couple of years ago we went to Mississippi for vacation, and it was a bit of a challenge. We cooked a lot.” (ID 07) “We just got back from a road trip. Oh, I wish there was some vegan fast food out there, you know, like, it’s not healthy. But sometimes you just need to go in for something quick to eat.” (ID 04)
	3.2 Social isolation	“Right now, it seems like my social group now really likes to go out to different restaurants and try, you know, whatever type of cuisine, so I wouldn’t want to not be able to participate because of my dietary restrictions.” (ID 06)
	3.3 Ability to prepare plant-based meals at home	“It’s easier to consume a plant-based diet as it’s faster. It doesn’t involve, maybe a lot of preparation in terms of cooking. So, for example, if I just wanna put together some like rice with some oil and vegetables that can be like you can assemble that pretty quickly.” (ID 06) “I’m about, I would say, 80% plant based…I eat [at] home. When, when I’m doing well, I eat [at] home, I would say, 95% of the time.” (ID 01) “Disadvantages are more time to prep and cook because a can of beans doesn’t taste as good as a piece of fish, and [bean is] just plain, you know.” (ID 10)
	3.4 Difficulties in preparing different diets in the same household	“So, for cooking together, it’s often a little bit difficult. My partner yesterday, for example, made some vegetable stir fry along with some chicken. She made the vegetables very separately, but I want cooked vegetables separately to begin with…because I won’t just like season them on a pan with nothing.” (ID 02)
4. Challenges in awareness and access	4.1 Lack of inclusiveness and understanding	“There [are] a few things we can order, and I like those things, but sometimes you have to ask them to tailor it, and they like don’t understand. There’s also like cultural and linguistic barrier that just makes explaining too annoying or atypical.” (ID 08) “It almost is like, well, if you don’t want the meat-based option, you’re some weird, special person who’s gonna ask for additional things and need to be accommodated.” (ID 06) “Sometimes there’s a kind of mild disappointment… I had several people trying to sell me to eat sushi in Japan…and then I’m forced to explain what my opposition is being plant-based…I kind of don’t want to box myself into that position [and] have to explain my life choice to everyone all the time.” (ID 02)
	4.2 Lack of education and information	“When we grow up…we don’t learn how to grocery shop or cook food, I feel like there is not meaningful thought or consideration given to how do we prepare, consume, purchase food as individuals in society… I think also just lack of education and like information about our relationship with food.” (ID 08) “Sometimes people who attempt to go plant-based or try to go plant-based don’t really have a super good grasp on the nutrition part of it.” (ID 05) “It’s not done as seriously. There are definitely calorie labels, for sure, but I feel like there should be a more of a macro breakdown as well. And proteins, fats and carbohydrates, because a lot of the time the plant protein is quite lacking compared to the chicken or something that they put in a meal.” (ID 02)
	4.3 Lack of availability of quality vegan protein sources in restaurants or grocery stores	“And especially if I’m eating outside, it is hard to get, like a quality protein source.” (ID 02) “Maybe other concerns, sometimes it’s hard to find vegan products in certain grocery stores that [are] better.” (ID 04) “But I think in the grocery store… like all the plant-based meat products or tofu, or something, is at the bottom, and there’s like a lot smaller selection… it’s not like featured to my eye in the grocery store.” (ID 08) “It’s very hard to be vegan if you want to eat out, way harder than being vegetarian…I just didn’t eat enough of like the tofu overall to get enough protein…I knew that I could do it with beans and legumes and grains, but I didn’t feel satiated, I guess.” (ID 10)
5. Perceptions on meat and dairy alternatives	5.1 Nutritional quality of alternatives	“I don’t eat meat substitutes regularly. I try to stay away from processed foods just generally. So I try to limit my meat substitute intake.” (ID 05) “They’re high in sodium - I try to avoid like super high sodium products and high fat. So, if they were a little bit more whole, I’d probably use them more often.” (ID 09) “I guess my partner really likes all the chicken alternatives. I grew up in a household [where] my parents really would always go for those types of things. But I also can view that as pretty processed, and probably has a lot of other things added to it.” (ID 06) “I drink primarily like oat and soy milk are probably my top ones, and I do use nondairy cheeses. Not a lot. I don’t really like to [eat them] because I feel like they don’t have much of a nutritional benefit, but I’ll do if I think it’ll add something.” (ID 09)
	5.2 A way to transition to plant-based diets	“When I first became vegan, I consumed a lot more of those because it was like, oh, this is like cool product. This is similar to something that I used to eat.” (ID 08) “I think that those alternatives…are a good thing for promoting a vegan diet, because it gets people to actually enjoy the food instead of just eating mush.” (ID 12)
	5.3 Taste and price	“It’s been really popular to consume dairy alternatives now for a long time…The alternatives to cheese…melt very weird, so I would go along with buying them if someone else really wants to.” (ID 06) “I don’t really consume them as much anymore, mostly for health reasons, and because they’re more expensive.” (ID 08) “It would be nice if the meat substitutes were cheaper.” (ID 05) “There’s a lot of like rapid improvement in making vegan food taste better…there’s a lot of really good vegan cheese options, but you have to know which ones they are.” (ID 12)
6. External facilitators	6.1 Healthy, cheap, and convenient options	“The accessibility of good, cheap, healthy foods is very lacking in the United States. But in the US, I get fries and burgers, or something like that, it’s hard to get good cheap options.” (ID 02) “I think if there were like very cheap, dense- protein options that would help…Some of the vitamins, if they would put them in more foods…the vitamins that vegans don’t always get.” (ID 12) “And just convenience. I think more restaurants that are like vegetarian-heavy would be really nice…to be able to have options when you aren’t able to cook, that would be more plant-based, that’s pretty rare at restaurants.” (ID 10)
	6.2 More recipes	“I probably need to try different recipes or ways of making a number of ways to make it, you know, more palatable, but I feel like the palatability of the food is quite difficult.” (ID 02) “In general, having recipes where I would waste less food. Because when I’m at my place, it’s just, I’m making food for one person, so then it becomes easy for food to go bad.” (ID 06)
	6.3 Support from other people	“I noticed that some of the people around me who have more hostility to even trying plant-based food…I guess about why that is because they just don’t know anyone in their life who is vegan or plant-based, and not just to share the benefits of it, but like to know how to do it…I think they just don’t know how to even get started.” (ID 08) “I think having people to do it with is always great. And so, working with my mom, we’ve always kind of enjoyed coming up with new recipes trying new recipes. We add them to her cooking book…So it makes it less burdensome and just more fun.” (ID 10)