I live to eat, so this is important. I love the wonderful cafes, inns, pubs and restaurants you find on the route. Fantastic diversity and always welcoming to walkers in my experience. If I am camping overnight in remote places, I try to eat at such establishments at lunchtime, or failing that, use the excellent Mountain House Meal packs and whatever looks tasty at the last shop. Plus of course, my own special recipe GORP (good old raisins and peanuts), to keep me going on the trail.
As for water, carry what you think you will need, judging where you can replenish. Some trails, at high elevation, are very dry at any time of year. The South Downs Way, for example, has few natural water sources on the downs but does have water points at intervals. Make sure you know where they are.
What I find very helpful, is to drink as much as you can before you start the walk, to make sure you start the day hydrated. Remember the saying “yellow or straw you have to drink more”? – so pay attention to your output colour. My input was 5 – 6 litres on the North Downs Way in summer, on other days in autumn, ½ – 1 litre is fine.
In colder months, or at campsites, I love Rooibos tea, in a mug or a flask. This wonderful stuff doesn’t stew, leaving a strong tannin taste and can be carried all day in a flask and it still tastes good. No caffeine as it is a diuretic, I leave my coffee addiction at home and usually I don’t drink alcohol on my walks either, although I love Real Ale.