What are you short of in your diet? Your answer would decide what you need to eat/drink during those periods. Probably on your way to the gym a Pre-workout could be fit in, but I just drink coffee and that gets me going. If your short on protein then maybe a protein shake. Short on carbs and lifting energy a banana or such. Short of healthy fats then nuts are the way to go.
To make sure you have enough energy to get through the day, why don't you try some energy bars or trail mix on your way to work and home? They're packed with protein and healthy fats to keep you going. Plus, they make for a great snack on the go!