It's very easy to spend that amount. We spend around that a week and buy only organic, fresh produce. Roughly:
£20 meat and fish ( chicken, salmon, sea bass, steak)
£20 dairy. Milk, greek yogurt, eggs etc
£30 veg and fruit
£10 odd other bits ie oil one week, rice the other etc
People's food bills only increase dramatically when they start adding processed meats, crisps, frozen stuff, snacks, drinks, etc etc. If people are eating meat/ fish, carbs and veg it's fine.
We eat out at least once a week dinner, once lunch, once breakfast. Which would add say £20 a week if eating at home so £100 ish a week