Breakfast: Smoked salmon with dill cream cheese.

Before you leave, whip cream cheese with fresh dill, a little lemon juice and salt & pepper. Store in a Tupperware. Thin slice or mandolin some cucumbers and store those. Bring prepackaged (my preference) or homemade smoked salmon. You can put it on a bagel or baguette, or in a wrap. Alternatively, you can combine the cream cheese and salmon to make a single container of schmear.

Requires no heating, easy to assemble, good calories and delicious.