Lunch??? I have lunch at midday, Ideally you should be eating enough not to snack but if it's to stave off sickness,
Couscous is free and you can add what you like to make it savoury or sweet.
If savoury lots of roasted mediterranean veg, garlic amd herbs.
If sweet then sweetener, cinnamon, Peaches, apricots, pears etc.
Jacket potato with beans and crispy bacon, and a side salad.
Or lots of simple to make soups.
Leek and Potato
Carrot and coriander
Spicy Lentil