Depends how much prep youre willing to put in, but even easy stuff can be healthy.
Gravy from the chilled isle in the supermarket (made with stock) goes well with your rice and chicken, all low fat and fairly healthy. Always get other people wanting my lunch when I heat that up in the office!
The freezer section has rice steam bags that have extra frozen veggies in over the tilda packets, or just add frozen mixed veg to the tilda ones?
Frittatas are easy to make and you can put a whole host of veggies/sweet potato/turkey mince in. Add trimmed bacon medallions cut very finely, gives you a great bacon & eggs start to the day without overloading on calories.
Home made egg fried rice is also easy, and much lower in calories than your take away equivalent, especially if you load it with chicken/veggies.