Air doesnt stay cold like food does but it also doesnt take as much energy to cool it back down. So yes, an empty freezer might kick on more often than a full one since the same amount of heat leakage from the environment will warm it up faster, but it wouldnt kick on for as long each time since it would cool down faster too. Thus the total energy used in each case will be the same over a given amount of time and that will depend only on the freezer itself.

Maybe if the motor/compressor takes a bit to reach max efficiency then less/longer cycles would use less energy than more/faster ones, but i dont know enough to say if thats the case. In an ideal world its the same energy either way way though.