I just want to add that weight gain has nothing to do with whether a dog is de-sexed or not. Our 5 year old neutered (at 6 months) female is a very healthy, lean and active dog because she is on raw food. She is fed an appropriate amount for her size and she is neither too skinny or too fat despite being half labrador. She's a shelter puppy herself and does not need to contribute to more unwanted puppies in the world. And there are enough roaming dogs in our neighbourhood for that to be a real danger.