It all depends on how long and fast the ride is and what your training level is. As you get fitter you will start burning more fat for fuel and you don't have to eat as much during the ride.

For early morning rides lasting about 2.5 hours, starting at 7am and burning around 2000 Calories the answer is nothing, nothing and a lot afterwards when I get home.

If it is a century ride starting in the morning that will have me on the bike for hours and burns 4000+ Calories:
I have a nice big breakfast, about 1000 Cal with milk, eggs, almond butter, cheese, bacon and home made bread.
Grab a banana and some 100 Cal bars for the ride.
Have a nice big lunch half way into the ride including a good burger, fries and beer.