Plenty of these in the fridge and freezer aisles of any supermarket! They usually come in a one or two-person container so they come in the right portions, and they also claim to be balanced and healthy. Most light ready-meals contain lots of protein (fish or meat), veg and carbs, and very little fat, to give you a normal amount of calories (300-350 Kcal per meal).
Our nutritionist says: "The main course is the most important, so don't skimp on the quality or the quantity, otherwise you'll end up hungry and start snacking. My advice is to make them healthier and more substantial by adding lots of extra veg."