Aggressive behavior

Question
I've adopted a Boston terrier  Chihuahua, Male neutered at a yr.old. He is sweet but aggressive when corrected. Growls or nips. Also he is food obsessed. He is good around other animals. Snuggles when he is tired, otherwise a nice dog. I would like to know the best training to correct his behavior as I do have experience with dogs, just not with such a high energy breed. Can you help please?

Answer
Stop correcting the dog.  Instead, use prevention, management, and positive training to alter his behavior.  Dogs that growl when punished are either frightened or defensive, neither of which is behavior you want to encourage.  It would help to know what behavior the dog is doing that annoys you into feeling that you have to correct it.  I would be happy to give you some force free ways to alter the behavior so that you won't have to get stern with the dog.  Also, when you say he is food obsessed, do you mean that he is protective of his food, or do you mean that he only obeys you when food is obvious and present?  A dog that likes food is a highly trainable dog, but you have to do it properly so that the dog doesn't only perform when you have a tidbit.  I actually never "correct" my dogs, I simply teach them behaviors that are incompatible with the behaviors I don't like.  For example, let's say my dog jumps up a lot.  I would ignore the dog completely, even if he jumps all over me, UNTIL the dog quiets down and has all four feet on the ground, then I mark that with "yes" or a click, if I have a clicker handy, and then reinforce with a treat.  Then, I simply lengthen the amount of time his feet must stay on the ground before I click.  Or, I might step forward a tiny bit and use the "sit" cue to have him sit BEFORE he gets close enough to me to jump on me.  Clicker training is wonderful to use with dogs that get aggressive, because it's non-threatening and positive, and hands off.  Recent studies show that being aggressive with a dog, even if you just think you are correcting bad behavior, tends to make dogs more aggressive, not less.  There are some free clicker training lessons at www.clickerlessons.com.  If your dog is food aggressive, then read "Mine! A Practical Guide to Resource Guarding in Dogs" by Jean Donaldson.  I actually use her protocols as a preventive strategy with puppies so that they never get food aggressive.