Thinking about it you are only paying £1.75 (ish) per meal!
Before I did the diet I added up all the meal's, takeaways, snack's, drinks (we have an onsite starbuck's), other drinks (eg wine etc) that I buy in a week. Added in the fact that OH would not have takeaways just for him & also he would cut down on snack's as we were not "popping" to the shop so often. Personally it decreased my weekly bill. Then following the diet you spend less on your conventional food so you are saving again! Try it! Even if it is a bit more than your weekly shop - is the extra worth it for the change in your life?
Good Luck
Nicky
CDC Swindon