I've heard that blamed on the EU for changing the diet of the British.
In 1972, before the UK became member of the EU, I was the first time in the UK, in London to be exact for 5 days, with a school trip of secundary school.
The reason was also the very comprehensive Tutankhamun exhibition in the British Museum, which was a huge thing at that time.
We visited the usual cultural stuff as well ofc incl the crown jewels in the Tower, had to see that musical "the Show Boat", and most importantly had a lot of secret meetings between the boys sleeping room and that of the girls.
It was also the first time I had as desert that glass like clear jelly in a terible cheap color on top of a dry cake.
In general the food available to us (small wallet) was to our taste terrible.
The only hot meal I liked was fish and chips
And I liked very much for our lunch the extra thin sliced sandwich bread with thick strawberries (you could choose between three thicknesses of sliced bread in supermarkets)
I guess that your diet changes are more coming from all those foreign cuisine restaurants and cheap take-aways with Indian curry and pizzas... are more coming from Brits on holiday in Spain, Portugal etc.... than from the EU.