I know that puppy food is a lot higher in fat than most adult food but I also know it's higher in calcium which can be bad for an adult dog. But is it bad enough that it is dangerous to feed to an adult dog or just not recommmended?! My dog is underweight just that kind of dog stresses his weight off and vets just recommond diets that he won't touch he is fussy as well which makes life exciting. My boyfriend brought the wrong food a while ago and it was puppy brand since he had already opened it and feed it to him I decided to keep feeding it. This now appears to be the most successful dog food I have tried with Chip he eats it which is always a bonus :-) So basically what I am trying to ask in a long winded way is puppy food bad/dangerous to feed to an adult dog?!?!

Yes, puppy food is much higher in fat and could be high in protein too. You don't mention what breed of dog you have.

I think it's probably bad if you feed nothing but puppy food. But I've heard vets recomend adding some puppy food to a dogs diet if it's really underweight. Pregnant dogs are supposed to eat puppy food along with the regular dogs food to make sure it gets enough nutrients & fat. So, I would say no, it's not gonna kill your dog. But I would recomend adding regular dog food to it to make sure he's getting enough adult nutrients as well.

My Dog is a hunterway(a heading dog) Dobbie cross.
I have been feeding him a adult dog food but only puppy biscuits as he won't touch any other biscuits fussy little brat

Hmm I didn't know pregnant dogs should eat puppy food. I learn something new on here everyday!

The only danger I ad ever heard of was the higher fat content.

Your dog appears to be a cross of two working breeds that are active so I would need higher fat to maintain and gain weight. I wouldn't worry much about the puppy food he's getting but if he puts on more weight than is needed, I would probably try to gradually move him to adult kibble. I would begin by first reducing the puppy kibble by gradually adding adult to the meal and taking away the puppy food. I frequently use fat to add flavor and to assist with weight gain without incredibly increasing the protein content. By fat I mean cast off grease, especially like bacon or lard. Cooking oil that has been used to fry meats or french fries is good. A little flavored fat on the meal can really improve a dog's appetite.

I feed my puppies and adult dogs the same food and this is raw meat products. I always have dry dog food, which I offer two- three days in a week, but raw meat is number one in their diet. First time I offer my pups bean size pieces of raw chicken, beef liver or kidneys, when they are 5 weeks old, as a treat. By age of 6-7 weeks, they eat some raw meat every day as a supplement. Usually I raise one litter of pups one time per year with 100% success. They are healthy, look sharp and they are playful. My oldest dogs live up to 14-17 years and they rarely see veterinarian, only in emergency cases, which are very rare. My dogs live active life and hunt and run loose for some time every day.