10-12lbs in 4 weeks is 2 lbs per week. You really need to loose that weight that fast? I'd drop the PWO drink, lower your carb intake a tad, veggies and fruit both being good, though fruit is little higher in carbs, but over all, 10lbs is not that much, I'd take it slow and easy, forget the zone, just eat the same forumla most always talk about, meat/fish, veggies, good fat, some nut seeds, toss in some fruit.
I keep reading that 80% of body compostition is made in the kitchen, balance from training.
So, since you got fat from the injury and did not back off your eating, now is the time to make minor adjustments, but again, 12lbs in a month is a lot, but it's your call.