when does your son come home and when (and what) is his next meal?
a sandwich is enough for a mid morning snack, but not for a midday meal unless the kids get another meal right when they come home. traditional wisdom has it that you should have a good breakfast and lunch, and a smaller meal for dinner. that's possible when the kids come home no later than 2pm but if they usually come home at 3-4pm or later then a sandwich is not enough to get them through the day.
I think you’re thinking of adult portions, but a sandwich and a piece of fruit is a lot of food for a child considering the volume of their stomach.
This could also be an overseas perspective because in my opinion (having just returned from USA) the single meal portions are very large in USA compared with overseas.
A sandwich and a piece of fruit will probably be in the 400-800 calorie range. It’s absolutely enough food for 1/3 meals. Especially if the kid is also eating snacks
depending on age a child needs about 1400-3000 calories per day. the bulk of which should be eaten in the early part of the day when you are most active. 400-800 is not enough for that.
the official US guidelines for school provided lunch range from 550–850. that's a bit lower than i would choose based on daily needs especially for older kids. breakfast and lunch should be more than 1/3rd each. dinner should be less than 1/3rd.
i am from austria. a sandwich here is considered a snack. not a meal.
3 meals averaging 600 calories plus a snack is completely reasonable. A sandwich is a meal. I don’t know what kind of sandwiches you’re eating in Austria but I don’t think it’s the same as me.
a sandwich is enough for a mid morning snack, but not for a midday meal unless the kids get another meal right when they come home. traditional wisdom has it that you should have a good breakfast and lunch, and a smaller meal for dinner. that's possible when the kids come home no later than 2pm but if they usually come home at 3-4pm or later then a sandwich is not enough to get them through the day.