Should it be against the law to discriminate against a vegan?

This has become an interesting topic for discussion recently; especially with the recent greggs-gate fiasco involving a simple sausage vegan roll. Initially I would have thought that most people would not take issue with what someone decides to eat or not eat, however, a recent poll by YouGov suggests quite the contrary. According to the statistics, 56% of those questioned do not believe it should be against the law to discriminate against vegans. Whilst 25% believe it should be. The remaining 19% remain unsure. 

Now we all know certain rights are protected by law. These can be viewed in the Human Rights Act 1998 and include characteristics such as ones sexuality, religious belief and race etc. However does dietary choice warrant protection via legislation? Furthermore, if so, to what extent? Would every restaurant be bound to offer vegan options? Could a vegan sue over a vegan related joke? Would not catering to non-meat-eaters constitute a hate crime? Yet, if for instance the Equality Act was updated to include veganism, then surely, would meat eaters not have the same rights? Would it not get to the point where vegan-only restaurants would be bound by the same law to offer a meat option?