Alternatively, a couple of scrambled eggs with a piece of toast and a bananna is fairly healthy.
A fried egg on an English muffin also isn't a terrible way to start the day.
Target ~400 cals, Try and get some protein and fiber in there. Watch out for saturated fats and high sodium (see the DASH diet for tips). If you are diabetic or risk diabetes, check out the glycemic index and shoot for low GI foods.
That'd be my advice (I'm not a doctor, what I'm suggesting could be 1000% wrong.)