The retailer opened the pop-up butcher, selling only plant-based meat, for three days in a bid to introduce more people to vegan options.
The outlet was so popular it had to limit how many products each customer could buy.
Speaking about the launch of the butcher, in a statement sent to Plant Based News, Buyer for Sainsbury's, James Hamilton said: "Whilst we're seeing a huge climb in sales of our plant-based foods, we know from conversations with customers that there is a sense of trepidation about cooking with them.
"So, our Meat-Free Butchers has been launched to encourage people to get up close to the products, try what they like and take home some valuable cooking advice and recipe inspiration.
"We have carefully selected the products on offer from the growing range of over 100 plant-based products now available at Sainsbury's, so customers are in for a real meat-free treat when visiting the butchers."
Unnamed protestors - thought to be linked with the 'carnivore' movement, which encourages a largely raw meat-based diet, took to the store to share their thoughts.
One of the of protestors held a sign saying: "Veganism is violence to humans, animals, and the planet."
Another held a sign saying: "Eat local meat, save lives."
'Free to protest'
The protestors were met with a mix of comments from vegans online with some condemning the protest, and many others confused about the message.
"I would like to know how he came to the conclusion that veganism is violence," said one. "It is a philosophy based on causing as little harm as possible, so I am confused."
"I think this is a ridiculous protest," said another. "But people have a right to protest peacefully, so what can you do?"
Plant Based News has contacted Sainsbury's for comment.