2 yr Male Black Lab

Question
When is it too late to neuter? And is it just a myth or does it calm thier behavior?

Answer
After the dog has made a desperate attempt to get loose and got killed dashing off in search of a female in season.  

While neutering after a problem behavior starts helps less, it should calm the dog down.  You, the dog, and everybody else will be better off if you go ahead now.  It also reduces the chances of cancer later.  The real myth is that the dog will become fat and lazy.  Dogs become fat because they eat too much for the amount of exercise they get.  

Your dog definitely should be narrower at the waist than the hips and chest. You should be able to easily feel the ribs, but not see them.  Each dog is different.  Standard recommendations are a good place to start, but each dog must have its food and exercise adjusted to its individual needs. Here is a link to a good illustrated guide, http://www.longliveyourdog.com/twoplus/RateYourDog.aspx