Michael Dello had been a vegetarian for two years when he decided to go vegan. The repercussions weren't what he expected.
"My girlfriend at the time said, 'I was embarrassed enough to introduce you to my friends [as a vegetarian]; how do you think this will make me feel?'" Dello says.
She felt he'd become a bore by taking food to the extreme.
Zerin Hassan had a similar experience when she made simple changes to her diet. She swapped takeaway, soft drinks and alcohol, for vegetables and sparkling water, causing controversy among her friends.
"Some make nasty comments about what I choose to eat or not eat. I will get comments saying, 'You're too skinny, don't you think you should put on weight?'
"At one event, [a friend] picked up a green pea and made a 'joke' that if she just ate the pea she'd be as skinny as me."
Nutritionist Fiona Noonan says these experiences are common, partly because when you eat differently to your friends, they can be worried you're judging them.
"It makes people look at themselves and their own eating habits, and they think you're judging their food choices," Noonan says. "There are also people who will judge your choice – and you – as boring."
"There's a stigma, and I think this is in part because there are these people [on social media] who are borderline obsessive about how they eat, and it seems to be their whole identity. Sometimes people want to cut you down, in case you're going to turn into that."
It seems even royalty is not immune from this judgment. Prince Harry has reportedly given up alcohol, caffeine and meat in line his wife Meghan Markle's habits. His friends are apparently saying he's calmer and healthier – but incredibly "boring".
Perhaps that's because they miss doing the things they once did with him – after all, he's had a reputation as a party animal in the past.
"Our socialising is centred around food and alcohol, and once you step away from the norm people don't always see it as a positive thing," Noonan says. "They want you to blend back in."
And some people who change their eating habits do let the ins and outs of their diet take over conversations.
"There's a fine line," Noonan says. "Sharing what you're doing and how great you're feeling with your friends is cool, but people don't want it rammed down their throat."
If you're considering changing your habits in order to eat "clean", here are a few suggestions from Noonan:
■ Reassure friends that there's no need to judge each other, and try not to worry too much about what others think.
■ Don't preach. "There is a risk of taking it too far and talking about it all the time, so don't become 'that' person."
■ Just be yourself. When you're eating well, you may find you have more energy and may be even more fun than usual.