If you eat something indulgent and fattening in leiu of eating an actual meal, does it cancel itself out?  Usually I have a granola bar at my desk in the morning for breakfast.  Today someone brought in these incredible homemade brownies with a whole layer of brown sugar, butter, and eggs.  She thoughtfully left them up at my desk in a tupperware container so that I could offer them to passersby.  Guess how many are left and guess how many were taken by passersby?  Guess how many times they were even offered to passersby - I wasn't going to waste these precious choclatey treats on just anyone.  Anyway, instead of my usual breakfast, I ate brownies.  However, I didn't eat the granola bar so I didn't really do anything bad right?  I just substituted one for the other. 

Similarly, there is an ice cream place within walking distance of my apartment that is open until 11pm every night during the summer.  Every evening an internal battle takes place in my head.  "I need ice cream."  "No I don't."  "But it's good to go for a walk!"  So if I give in and get the ice cream, does the fact that I've walked over to get it cancel out it's badness?  How about if I decide not to have actual dinner and go get ice cream instead?  Makes sense to me.
  ¶ 5:06 PM