Serious question: how is this enough calories for lunch? Assume you need 2,500 calories/day. Suppose you need a third of those at lunch, that's 830. (And given the traditional light continental breakfast, I'd expect an even larger lunch to compensate, so probably closer to 1,000.) A single sandwich with three layers of bread and three single layers of cheese or meat, can't be over 400 calories. I'd be starving and un…
So I'd have 100% whole grain bread with lean meat and some cheese. I'd use a flavorful cheese so I didn't have to use too much in order to not go over budget (in terms of calories). I used things like mustard instead of butter.
With this I could go about 5 hours without feeling particularly hungry (office job).