As others have said, there are really a lot of variables involved. As the PP mentioned, you should also keep in mind that you might not be sat immediately at your ADR time. Most times, you'll be seated pretty close to your ADR time (I'd say less than a 15 minute wait), but I've had waits of 45 minutes or more past the ADR time ('Ohana, BoG, Citricos, and R&C were the ones where I've had long waits; not consistently, but it's happened). The ADR means you'll be given the next available table for your party size after you check-in and the guests with ADRs that have checked-in before you have been seated. After that, I've found that food normally comes out pretty quickly after ordering (~10 minutes), but again, this can depend on the kitchen, how busy they are, if they're having issues, etc.