my husky needs to put on some weight

Question
I am trying to put weight on my red/white husky.  Male/almost 2 yrs old and little over 50 lbs.  Vet said he was a little under weight and suggested changing dry food to puppy food-changed from Beneful to IAMS puppy-lg. breed.  He is so picky and only eats it with canned food-he is getting picky with canned food now and really has never been a big eater --he is on heart worms, reg. checkups-I am about ready to change vets-I will buy whatever it takes
HELP -  do you think he needs tests?

Answer
Possibly, although my first instinct is that he is just a lean dog and may be not getting enough high calorie food.  Try making sure that his food has higher concentrations of fat and protein, and you may want to begin supplementing the food with some meats (human food).  I usually give mine some hamburger, and they love it and do well with it.