Potatoes are good for you. If you are on a diet, potatoes are not the enemy. Potatoes are highly nutritious, relative to caloric value.
(Yes, I know all about the potato famine. Do you know why the potato famine happened? Because the population of Ireland had exploded. It exploded because of potatoes. After the "discovery" of potatoes, and their introduction to Ireland, the population increased ten-fold. An acre of land would support ten times more people than it had before. Potatoes are good stuff.)
A small to medium potato, at four ounces (or 100 grams), is only 70 calories. The potatoes they give you in restaurants are often 12 ounces, but even that is only 200 calories. As long as you don't load them up with butter or sour cream there is no reason you can't have potatoes.
I'm not big on fish. I was fed lots of it when I was growing up. It isn't any treat for me. Besides which, I really hate fish bones. But, I know it is nutritionally rich. High protein-to-calorie ratio. The "right kind" of fat. (At least, that's the case with tuna and salmon.) I was delighted to find frozen salmon "bricks": "fillets" from some commercial outfit. I know foodies will have a fit: they are frozen, they are unnatural shapes, etc, etc. But I haven't found a bone in a single one, and I like that. Besides, the nutrition is the same. Yes, it is counted with some kind of "butter" marinade, but, if you broil them, most of that runs off. 90 calories per. They take 20 minutes in the oven (or 15 if you crank the temperature a bit).
Being so good on the potatoes and fish, I can probably afford to do frozen veg. (Yeah, I know, the foodies are off screaming in the corner again. Sorry, if I take four hours to make dinner, I don't have time to write.)