If you don't want any drafters, a can of beans will do the trick.
I ride so slow that I don't need anything special for a ride. I think for the guys that are going full out some carb jells and such help keep their energy levels high.
You will have to experiment to see what works for you. I think that high fat meals are going to make you sluggish. High carb meals may make you start strong and then feel depleted. If you like steel cut oats, that is probably a great meal before a ride. Oats have a great history behind them like the Roman army eating oats and marching long distances.