Very common behaviour and not at all to do with hormones or your dog being aggressive. Below is a fact sheet on food and bone guarding.
I would do the following to ensure that your dog is happy with being approached while eating or having a chew.
If your dog is happy for you to approach his food or bones when eating, make him even happier, by adding to that food some higher value food like liver. Do this regularly.
Don?t give him things that you later want to take off him. If you do have to remove a bone and you are not confident of your dog?s reaction, call him into another room away from the bone. Bones and chews above all things are more likely to bring about food guarding behaviour because they are long lasting resources.
When my dogs are eating bones, I go to them and give them another bone. When my dogs are eating, I add food to their bowls.
You could go as far as hand feeding your dog can to help make it understand that human hands PROVIDE food, not take it away. I often use my dog?s daily food for training purposes and this means I may feed my dog from my hand 100 times a day (tiny portions). They like my hands. Other people do the same ? they like other peoples hands.
If you dog is the sort of dog who will have a bone, chew it, then leave it, but guard it from a distance, then only feed him bones when he is hungry enough to eat them, of the type that he can actually totally consume. Or give them in another room and leave him to it.
If ever your dog growls when eating or at any other time, remember he is only saying, ?please don?t take my bone? or ?please stop doing that?. If I said to you, please don?t take my chocolate would you scruff me or pin me to the floor??? If you did do that, do you think that would benefit our relationship? Do you think that it would make me respect you more???
If a dog growls and you leave him alone then he learns that growling is all he needs to do. Growling is not aggression, it is designed to prevent aggression. It may be undesirable, but it is not aggressive in itself. If you never remove food from your dog he may learn that even growling is not necessary.
If a dog learns that you always provide food and more food or bones and more bones then he is unlikely to guard his food at all.
If you have confirmed food guarder and do not feel confident to try any of the above, then just feed your dog in another room, where he will not be disturbed.
At least this way, the food guarding behaviour is not likely to deteriorate.
If your dog regularly guards things or is over protective of his food, toys or other items, and you don?t feel that anything in this document can help, then GET HELP from someone and soon. Unwanted behaviours rarely just ?go away? of their own accord, but they are, very often, very easy to resolve once proper understanding is brought to the situation.