I got to fill in one Sunday Morning for a pastor who was out.  I love talking about this subject.  Not just fitness and nutrition but how it relates to a bigger purpose.  Exercise is a gateway drug.  I've noticed as people improve their physical health that improvements happen quicker and easier in other areas of their lives.  You WILL be motivated after hearing this talk.  (note: I recorded this in the church so there is a little echo, I'm no sound engineer, it's worth the listen still)