tips on dropping slowly

Need you guys to critique my diet a little bit. Work a very physical job Mon thru Fri at night about 4 hours. Best I can figure I burn between 1500-2000 extra calories those nights. That makes for a problem I've never had before can't gain weight, or lose slowly to keep as much muscle as possible.I am currently 6ft 4in 230lbs not on cycle. This is what my diet looks like.
Sun-Tues-300g Protien, 250g Carbs, 70g Fat split into 5 meals. One of those being dextrose80g and whey40g after workout.
Wed-I spike it up to get my fullness back around 700g carbs, 300g protien, 100g fat.
Thur-Fri-Same as Sun-Tues.
Sat spike it up again.
Supplements are 30-40 grams of glutamine a day, 3-6g vit c 2 megamen multis, around 5 g arginine 2 after workout, fish oil caps 6g a day.

I am trying to lose around .5 to 1 lb per week. Any help with supplement sugg or diet tips would be greatly appreciated.