Hmm, I'm finding this thread really interesting. I've been fortunate enough never to have to feed us for £1 per day. I'm not much of a cook, so if I really had to, our menu would look something like this:
Breakfast - porridge oats with whole milk (40p for 2 portions including cost of milk), small cup of milk for DS (probably around 15p), share a banana or an apple (15p). So we're already at 70p just for breakfast.
Lunch - 2 fish fingers each (12p per fish finger so 48p in total), small can of baked beans (24p) plus some frozen peas (15p). 72p
Dinner - with only 53p left, it would have to be something really cheap like eggs (8p an egg so 24p for four eggs) on toast (you can get an 18 slice loaf for 45p so 5p for 2 slices). So that's 29p. That leaves 24p. I'd probably let DS have a slice of cheese (5p) and a value fromage frais (7p) before he went to bed to stop him feeling hungry. Total 41p for dinner.
For snacks we could then afford one slice of toast (15p) and one piece of (cheap) fruit between the two of us. That would bring it to half a penny over £2.
Personally, I'd have to massively reduce DS's milk consumption to fit within the budget, change where I shopped and the brands I bought and we'd be eating 4 portions of fruit and vegetables a day rather than 7. It also wouldn't look very appetising. I've realised how much I rely on being able to pick up a nice piece of meat or a ready-prepared salad to have food that appeals to us
.