I think I spent about £40 p/w last year, that felt like a lot for me!
What on earth do you buy?! I'm not judging because I'm pretty greedy but I really hope that price includes alcohol or something!
Buying basic stuff (flour, eggs, veg, fruit, milk etc.) and making your own meals is the cheapest, tastiest and healthiest option, but if you totally hate that... some of the value ranges in supermarkets DO taste good (and trust me, I'm fussy). The best thing to do is cut out the really bad stuff that you don't need.