Problems with a food aggressive dog
Food aggressiveness in dogs has many reasons, the most prevalent ones being:
A dog has some basic and very simple needs additionally to food, water and shelter. These are knowing its place in the rank order of the pack, getting enough exercise and mental stimulation (especially important for dogs of the working dog breeds), company (don’t forget, a dog is a pack animal, not a solitary one) and the possibility to socialize with other dogs / animals / humans during its infancy.

photo credit: Tambako the Jaguar
If these needs are not met in a satisfactory manner, problems in dog behavior can arise. Proper socializing starts with teaching the dog the fact that ALL humans are higher ranking then it. This is especially important if children are around. A dog should never be allowed to take on the role of the highest ranking alpha member. This you achieve by setting it boundaries and routines from the beginning.
Dogs should always eat / been fed after the humans have eaten as this imitates the natural pattern in the pack with the alpha animals eating first and all others later.
Establish routines for feeding and other activities. Use always the same commands, times and places for the same activities. So, for example, for feeding a dog that tends towards food aggressiveness, you want to feed it always at the same time, the same place and let it first obey some simple commands like “sit and wait”.
The more nervous the dog, the more calm should you and the surroundings be. If the dog acts up, stop the activity and ignore the dog until it has calmed down.
After the dog has eaten remove leftovers, where no food, there no food aggressiveness
If you have several dogs / animals feed them according to their pecking order, the higher they rank the earlier they get fed.
Take care that the dog gets enough exercise and mental stimulation. Make sure you understand the needs of this for your dog breed exactly.
If these simple tips don’t help and your dog continues to be aggressive, with or without food around, please seek urgently the help of a professional. Your vet or your local dog club can point you in the right direction!