If you have a sore mouth and throat after treatment then you will probably have difficulty in chewing foods. Try to make moist meals by adding gravy, sauces, butter, margarine, milk, custard and/or cream. Soften foods by mincing, liquidising, mashing and chopping.
For example:
Avoid dry, rough foods, e.g. toast, crisps, raw vegetables.
If you cannot manage soft foods then try chilled or frozen nourishing drinks and supplement drinks, e.g. full fat milkshakes, full fat milk, yoghurt drinks, Complan, Build-up, which can be obtained at supermarkets and/or chemists.