Try an egg for breakfast. Boiled, scrambled, poached or even fried. With a couple of slices of toast and a smear of butter and marmite. You could start brekkie with cereal with a chopped up apple or banana with yoghourt and some milk. Lunch - sandwich made with some sliced meat and salad (lettuce, tomatoes, cucumber) with a piece of fruit for pudding. Or grated cheese sarnies with - again - tomato or some fruit chutney for a change. For supper try fish (grilled or fried), potatoes, maybe mashed or whole, different green veggies or salad. A lamb or pork chop, chicken joint - or a pasta dish made with tinned or fresh tomatoes, mince, grated cheese and whatever veg you can grate (i.e. disguise) in the sauce. We used to have a 'sweetie' day once a week when my children were allowed to buy/eat whatever sweeties they wanted. Mars bars, crunchies, turkish delight, cola type sweet things, juicy fruit things, etc etc. But they could only devour these AFTER they'd eaten their tea. And then they had to clean their teeth!