Good Diet Plan?

Ok so I have decided to get back on my horse to try and lose approximately 40lbs. I decided to try this Insanity video, by recommendation of friends and family. I do also play basketball when I get the chance, because I am in Pharmacy School right now. So being in school the hard task is being consistent. I know exercise by itself won't do it, so I am wondering what is a good diet plan. I do love chicken, I can use that as my protein every day, but the next thing is making a variety of other things to help with a diet plan. Normally for lunch I try to stick to a turkey sandwich on wheat (6 inch) from subway with a bag of chips and diet soda. I have tried to stick to some chicken and broccoli for lunch and dinner, but fell off of that horse after 3 weeks if that. For those of you who into fitness I can use some help to stick to it. Thanks in advance.
Good Diet Plan?
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