I have lived by myself for a long time, enjoy food, and do have three meals a day. Brekkie is cereal (porridge in winter and branflakes in summer), lunch is usually something with eggs. I slice of toast (good quality bread), with half a tin of low salt, etc baked beans topped with a couple of poached eggs, cost about 60p. Other days I may just have a couple of boiled eggs with a slice of bread. Sometimes in the winter I make up a whole lot of soup, which I have with a roll. All of these lunches work out well under a £1 each and take just a few minutes to prepare.
Tea is my main meal of the day and I have fish with salad or couple of pieces of chicken breast or drumstick, again with salad. Never purchase ready made salads, make up my own and with careful storage only need to buy once a week. sometimes I will boil up a few potatoes to mash. Once a week I have one of my daughters over after work for chat and tea, so will splash out a little more then. Home made shepherds pie, or fish pie type of thing. If I fancy a dessert it is usually a yoghurt.
Stopped buying fresh veg years ago - only like shopping once a week. Find frozen are easier and fresher. Not too keen on fruit, maybe the occasional banana.
I eat healthy and well, but reckon that food should cost me no more than a maximum of a fiver a day and I do not shop in Lidl or Aldi, do not like them - continue with Sainsbury. Obviously my weekly shop does include all toiletries etc. and I reckon on spending somewhere between £40- £45 per week. Only on very rare occasions can I use the £50 plus voucher!!!