We don't get takeaways/delivery/fast food for meals through the week, about once a month DH and I will order in Chinese or pizza for us after DS has gone to bed (DS wouldn't touch it anyway!) and for meals I don't buy frozen foods or things like chicken nuggets for meals, I make them homemade for him when we are having them. So fast food like McDonald's is reserved for times when we are out and plan to be home for lunch but then something goes wrong or plans change last minute and DS starts moaning that he is hungry and anything else would be ages. So maybe once every 2-3 months? Or it might end up being twice in a 3-week period but then would not happen again for 4 months...kwim? But tbh DS doesn't really like McDonald's that much, he begs to go but it's because he wants the toy from the happy meal.

He will only eat nuggets, not burgers, and if he eats two full chicken nuggets then I have to say that DH and I are very happy. Maybe 10 french fries and he always chooses a bottle of organic milk for his drink.
BUT my DH does love to go to McDonald's for breakfast, DS has always eaten by the time he/we get there and so he has pancakes and milk. Or a toasted English muffin with jam.
My DH takes DS out regularly on a weekend morning (usually swimming) to give me some time -- usually it is time to clean the house or it is when I am getting groceries and they don't want to come, but it is also good for them to have time alone and not have me there nagging about everything. And he almost always stops at Subway for lunch on the way home. It's part of their thing, DS loves it (doesn't eat much of his sandwich, he is SO fussy) but he loves the ritual and routine of it, the time spent together, the fun they have, the fact that he feels they are doing something really special and a big sneaky, because if I was with them and DH asked if I wanted to stop at subway I would say no, insist that we either go to a real restaurant or go home and not spend the money....so they only get to do this because they are alone, kwim, and it is all really a bonding thing for the two of them. If it was McDonald's and not Subway and it was EVERY week I would ask DH to try to find some alternatives for now and again but I'd also leave it to him to make the final decision....but I do also know that my DH would take that on board what I have said.
My DH does also always take a lunch box when he goes out with DS. It's habit, we try to take one any time we are going out at all (to avoid random stops for lunch when we don't want to!) with cut up fruit, a banana, a sandwich, crackers, carrot sticks, tomatoes, etc etc.