Don't buy, won't buy - margarine, seed oils, skimmed milk, non-dairy 'milk', low-fat versions of things, artificial sweeteners, palm oil, fruit juice except tomato juice, things marketed as snacks.
Staples - fruit, vegetables, mushrooms, tea, cocoa, rashers, fresh meat, assorted deli meats, nuts, dried fruit, butter, lard, assorted cheeses, natural yoghurt, whole milk, double cream, creme fraiche, olive oil, anchovies, olives, eggs, canned tomatoes, chickpeas, frozen peas, green beans, spinach, berries, wine, all sorts of spices and seeds.
Always have salt and sugar in the house, usually have coffee though I don't drink it myself.