The trouble with dieting is that sometimes the metabolism slows down and you won't burn as many calories. Try weight lifting to increase human growth hormone and testosterone levels. That will increase muscle mass which will cause you to burn more calories than when you didn't have the new muscle. While you are gaining muscle and losing some fat, your total weight may actually show a gain. The key to weight and health is to measure your percentage of body fat. Chart your lean muscle mass, body fat, etc over time to see how you are improving. Some body builders don't do a lot of aerobics.
Diet: check out the Zone diet 5 daily meals without a lot of exercise, 7 daily meals with a heavy exercise program. The formula is really easy. Don't buy the book--too scientific and technical--who cares. Check out the website www.zoneperfect.com where they have a one week trial diet. The formula is simple, at each meal you ensure that 40% of the calories come from carbs, 30% from protein(builds fat buring muscle), and 30% from fat (slows the uptake of carbs-->insulin-->fat). Good luck. Remember, not your total weight, but your body fat percentage.