Diet and exercise

how much is enough? I am looking for some concrete with exercise, for example is 4 days @ 45 minutes a session enough? Or should i do 5 or 6 days a week. I tend to over do it, either exercise too much or not enough. I want a plan I can stick with. I have a lot of knowledge about exercise for example the need to change routine often. Add weight resistant to the training, because muscle burns more calories etc. No one ever saids how much or how often. You hear people talk about walking , but we all know thats not enough for real results. If you are doing nothing and then start walking great, but really in time you will need to change the time and the amount of the exercise in general. Also when you exercise should you eat enough calories to make up for what you burn? I am 5' 8" male 210 lbs now, would like to get my weight between 170-175 lbs. I can achieve that goal pretty easily, but I want to keep it off for good. I have foods that I must have, but can limit what I eat. Like I said in the begining I tend to over do things. If I am exercising and diet fine, but if I cheat big trouble. I do not want a diet I want to eat for life. I like convience foods that are premeasured, so I know what I am eating and how much. I also like taste and to have foods that last for a while. what are some good convient foods out there? Thanks for any help you can provide.