I just recently started eating two meals a day, hence digging up this thread. I've found it has a few challenges.
One -- meal size. I'm a stocky guy, and increasingly active, so I need my meals to be big and filling. This has meant upping my carbs a bit, but also keeping up good energy sources, like salmon. If I don't get enough calories, I'm more prone to binge.
Two -- what macronutrients to eat during which meal. I feel better if my first meal is mostly fat, with some protein (i.e. eggs, yogurt, fish, etc), but my second meal protein with a fair dose of carbs (meat with veggies and tubers). The second meal being heavier on carbs also has improved my sleep. In either case I eat big portions to meet my caloric needs.
Three -- hydration. If I drink enough water, two meals is more than satisfying.
Last -- this is harder to do on workout days, but I'm still working on it. In any case I've gotten good results and am getting leaner and stronger. It seems that my best workouts are between meals, with fats for energy and carbs for recovery, but I'm not sure if this affects me burning fat stores.