I could not have my grain in the morning until many months in. The first time I tried it I was starving all afternoon too. Try going back to a Phase 1 breakfast and adding your one food later in the day.
It's going to be trial and error for awhile as you figure out what works best for your body. That's why a lot of us recommend Phase 1.5, add one food at one time and see how it works. If you have any trouble with it try it at a different time or try a different food. That way you get a really good sense of what works for you.
Baby steps, losing the holiday excess first.
Maintaining 48 lb loss since 2008, working off regain to a sensible maintenance level. 60+ lbs and counting!