The ADA recommends that the general population have a snack about an hour before a workout. The snack should be relatively high in carbohydrates and moderate in protein while being low in fat. Also, keep in mind the Glycemic Index of the food. A banana is often a safe bet for many people because it has a GI of 70, which is high. Foods with higer GI scores will cause a faster rise in blood glucose, which is good for a workout.
You might want to look into casein protein. It’s a slow-absorbing, complete protein that is generally good for supplying your body with continuous amounts of quality protein over a period of about 8 hours, or while you sleep. Do some research on this and as always, consult a registered dietitian before you make any big changes in your diet!
I hope this was helpful!