You learn to eat your necessary nutrition in 30 miles not 30 minutes. You Start off with cooked protein of some kind, followed by some form of bread or potato and then finish with a green and some kind of desert. A little dab at a time from the doghouse next to you or off the dash under the windshield as you roll.
We used to have two Dutch ovens going on the floor near the shifter. It would contain chopped ham, taters small, some onions (This is a type of food you have to have etc) and something green like brussel sprouts. Takes 6 hours to cook. You have 4 or 5 to go when it's done and ready to eat. and there is chopped tomatos and some form of drink and so forth to finish.
I don't know too much about day cabs, but we used to call ahead to whatever truckstop and have them precook and wrap in foil a particular way of meal. If I remember right in the morning I asked for a western omlette with everything, easy on Jalapenos, and then some form of potato to go with it and perhaps a bit of meat with it so that it all cooked together, wrapped in such a way you just break off as you eat going down the road.
Philadelphia Food trucks of the old roach kind with cheesesteaks, taters and onions and so on, wrapped you a few extra for the next few days for a 10.00 or so you did not count on actually pulling INTO a formal truckstop and then wasting time with all that served meal, parking and so forth. You needed to be down the road. They are waiting on you.
The three Stanley thermoses contained the jewel collection, good stiff coffee in two and strong alcohol in the third marked as such. This would be way before the CDL days where they put a stop to that. So the third contained known good water (Usually from distilled gallon jugs which broke) The spirits were not for drinking however. Its for cuts and trauma you accumulate eating splinters throwing pallets all day in the trailer. Otherwise you run a bad fever from being infected and then get really sick. Then you cannot drive. And lose your income if not your life.