Man, this is an extremely tricky issue that I have never seen anyone adequately address, though John Berardi tries really hard. I really wish I could find a reliable formula, but I doubt any formula can possibly take into account things like indvidual metabolism. Therefore, individual experimentation is key.
Another problem is that much fitness advice is written by people who have never had high bodyfat levels (Has John Berardi ever *not* seen his abs?), so it's hard to be sure that their advice will work for people who gain fat easily and are probably insulin resistant (myself included).
1456 cals/day sounds really low, though I think the good macronutrient ration of the zone will help counteract some of the harmful effects of extreme dieting. What concerns me is that you say you've been doing this for a month, but you havent' seen any changes *and* you feel weak and tired. That's a bad sign. Though it could be that you are still adapting to the diet, it could also mean that you've gone too extreme. If you can keep it up for another 2-4 weeks and you still haven't seen any changes and are still feeling bad, I think you may need to make some changes.
Of course, all of this assumes that you are in fact eating around 1456 cals every day and getting some exercise. You need to be sure about the former. It's very easy to deceive ourselves. Keep a food log.
Perhaps the most surprising thing is that your weight hasn't changed at all, so at least you aren't losing muscle. Try taking waist measurements as well. Honestly, you can't go much lower in calories, so increasing your exercise is about the only option remaining. Just do it gradually.
I say "about" your only option because there is still the option of adjusting macronutrient ratios, which Robb says not to do until you reach 10% bodyfat. But if you increase activity levels, and you still haven't made any gains in another month, I would certainly consider it.
Best of luck and keep us posted,