Three in five vegans say they have “relaxed” their principles when eating.

A survey by Zizzi also showed that 73% of those with a form of gluten intolerance had still ordered while eating out even though no gluten-free option was available.

The poll shows 64% of respondents said that either they are themselves, or they know, a fussy eater but that 68% said that they have, or they would, compromise on their own eating habits in order to help diffuse arguments.

When asked which diets are the hardest to cater for, veganism came out on top, with non-gluten diets a close second.

1. Vegan (20 per cent)

2. Non-gluten or coeliac (18 per cent)

3. Non-dairy or lactose intolerant (11 per cent)

4. Halal (10 per cent)

5. Kosher (8 per cent)

6. Vegetarian (7 per cent)

7. Low-fat (6 per cent)

8. Diabetic

9. Low-sugar

10. Nut allergy

Jo Fawcett, Marketing Director at Zizzi, said: “We are proud of the diverse selection of dishes we offer at our restaurants nationwide. With specialist diets now commonplace, we understand the importance of being able to cater to a range of preferences and needs.

“Our inclusive offering of vegan, non-gluten and low-calorie dishes alongside our popular indulgent pizzas and pastas are proving to be more and more popular with customers who are realising they don’t need to compromise when dining out with family members who have different requirements.”