lunches should ideally be the biggest meal of the day. It really depends on how much you're eating the rest of the day... breakfast- 400 cal midmorning snack- 100 cal lunch- 500 cal snack- 200 cal dinner- 400 caI Im not sure about fat grams though, so I can't help you on that. This adds up to 1800 calories.est Answer: Lunches should be around 500 calories or less for girls, not to sound sexist. For example you can get a six inch turkey sandwich at subway that has 280 calories.