Consumers are buying vegetarian meat alternatives believing they are sources of protein - but some may contain very little at all, new research suggests.
A report from Safefood, the all-island body promoting food safety and healthy eating, said one in four meat alternatives resembling products such as burgers, sausages and mince is not a good protein source.
One in three of those surveyed said they bought the products because they believed they were healthier.
The vegan food market is one of the fastest growing globally over the last five years, with UK sales of meat-free products forecast to top £1bn by 2024, Safefood said.
Its research assessed the nutritional content of more than 300 meat substitutes sold in supermarkets across Ireland.
These products are marketed alongside foods that provide protein, including meat, poultry, eggs, fish, nuts and beans.
But Safefood said they may have a different nutritional value.
Dr Catherine Conlon, director of human health and nutrition with Safefood, said: "Judging by the number of vegetarian meat alternative products available, there's clearly a market for these as plant-based alternatives to meats such as beef or chicken.
"From vegetarian meat alternative burgers to sausages and mince, these are popular choices for many people who want an alternative source of protein in their diet or want to eat them for ethical or environmental reasons.
"However, one in four of the products we surveyed was not an adequate source of protein.
"When we asked people about vegetarian meat alternative products, a third thought they were healthy or better for them.
"However, many of these plant-based products are simply highly processed foods. If you think about it, eating a sausage roll, whether that's plant-based or meat, is still a sausage roll."
More than one in three adults who responded to a Safefood survey said they eat vegan or vegetarian versions of burgers, sausages, chicken or fish. Of those, three in 10 (32%) said they consume them once a week or more frequently, with almost one in 10 (8%) consuming them daily.
The most popular meat alternatives are mince, consumed by almost half of those who eat meat alternatives (41%), followed by chicken (34%) and burgers (31%).
The main reasons for consumers purchasing them are that they are perceived to be healthy or better for you (33%), for taste (26%) and their environmental impact (12%).
Dr Conlon added: "There are some positives to these products. Some are lower in fat and saturated fat than their meat equivalents, while others are a source of fibre. But if people are considering these as a protein replacement, I would encourage them to check the label.
"The reality is that these are processed foods and a bit of a mixed bag.
"If you are going to eat them, read the label and look for products that are a good source of protein and lower in saturated fat, sugar and salt.
"There are lots of protein sources that you can choose from, including meat, poultry, eggs, beans, lentils, nuts, tofu and chickpeas."
For more information see safefood.net.