Yeah, I'd definitely say so. A sensible dinner for me was usually a chicken breast or stir fry (go light on the oil, though!) and a bunch of vegetables. I'd usually always have an apple for dessert, too. You may find that you lose weight too fast this way. If so, you would want to add calories to your lunch, but not dinner. I guess that also depends on when you're riding, though. If you're doing after dinner rides, then you'd be fine to eat more for dinner.
Keep a spreadsheet of your rides and your ride mileage, avg. speed, etc. This helped me a lot in obtaining goals, and it's a lot of fun to look back on your progress.