Sugar free jello -- the only problem is that I can kill a whole container of that stuff in one sitting.... (BAAAAAAAAAAAAAAD habit!)
As far as the empty stomach quandry -- generally the optimal time to burn fat is cardio in the AM on an empty stomach. 45-60 min -- also check out the "When 30 + 30 NOT = 60" thread (search on WarLobo as author & "30" as the search criteria) at a low but intense pace (e.g. steep incline walking fast on the treadmill). I have to hit it between 6 - 7 am BEFORE I start getting panic-level hungry. Alternatively, do cardio after you lift. But don't lift on an empty stomach. The two most important meals of the day are breakfast (it gets you going after an 8 hr fast) and your post workout meal -- it refuels you after a heavy workout. Its a good time for something like a protein mix + some simple carbs like Ultra Fuel (Twin Lab) with some l-glutamine. Then eat some protein & green, leafy carbs like 2 hrs later (no starchy carbs) - this is what I use when I work out at night (usually 7-9 pm).
If low impact 45-60 min cardio gets boring or you've been doing it for a while (e.g. 6 weeks) then switch it up with some interval training (HIIT) for 20-30 min. Just like with your diet, if you keep doing the same thing, eventually your body gets conditioned to it and it won't respond as well. It needs to be stimulated and challenged constantly! And also follow what your body tells you -- if you are getting burnt out, getting bored w/ the diet, not sleeping well, etc. dont' be afraid to take some off and just recover. Another word for "over training" is "under recovery" and its just as important as diet & training.
I also dont' think anyone mentioned cheat days? Definitely allow yourself at least a cheat meal once/week. Sometimes you may need a whole cheat day, but I think that if you are looking for serious results, a full on cheat day can set you back too far. You need a break from the diet just for your comfort & sanity, and it also gives you a carb load meal to help stimulate your diet occassionally. As new@ & I think phem said, you get to the point where you actually feel like crap if you junk out on your cheat day. At that point, just keep eating clean, just more.
Challenge yourself to stick to the new "lifestyle" for 3-4 weeks and see how you feel at the end of it. You'll probably see some exciting results and want more!