Lost allot but need to lose more!!

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Hey all! A few years back I went from 289lbs down to 195lbs. I didn't lose the weight correctly as I basically starved myself and lost it all in less than a year. Yes, just as everyone says, over the course of the last 10 years I've gained it all back plus. Now I'm trying to lose it in a proper manor. I got up to 338lbs which is my all time high. I went on a vigorous diet/exersize plan consisting of a 2hr workout every day and about 1800 calories. I got down to 269lbs but it was just to hard to stick with and once again I fell off the wagon and went back up to 285lbs. So now I'm trying a more subtle approach to lose and stick with it. I've managed to get back to 281lbs but I feel I should be losing the weight a tad faster. My biggest confusion is how many calories I should take in per day to get to my goal weight in a reasonable amount of time and maintain it. I'm a big framed guy at 6'1" tall with a 13D foot and 14 ring finger. My lifestyle is between sedentary and light activity as I'm an electronics tech by trade which sometimes has me out and about doing a lot of walking and working off ladders but sometimes requires me to sit a lot. My weaknesses are pizza, sweets and alchohol. I usually drink a few whiskey/diet coke mixers once or twice a week. The sweets are daily and the pizza is once or twice a week. I've tried to cut them out and that just isn't going to work. Any input is appreciated!