I have a 4yr old German Shorthaired Pointer. Over the past month he has seemingly been losing weight. We have 3 other dogs and none of them have this problem. I started increasing his food intake, and keeping him indoors out of the weather. Of course fresh water. I read that he needs a premium dog food with MEAT as a first 5 ingredient. Add canned dog food to the dry dog food. Are there any recommendations? I can't afford a vet, but I don't want to lose my dog! Thanks for the help!

Get a fresh stool sample to the vet. I know you said you can't afford a vet but a stool sample should only run about $16. If he has worms the vet will see the ggs. Wrms do not go away and can get really hard on the dog.

Yes, a lot of vets will run a sample for you without having to pay a consultation fee.
Worms can definitely make a dog drop weight, and suddenly too.
Does his tummy look bloated but skinny across his back?

Worms are obviously the first thing to look for as the above experts have said when a dog is losing weight as you described. Heartworm medication every month is crucial, especially if your dog gets into "nasty" stuff like feces and dead animals. Meat should always be the number one ingredient in dog food, however, dogs primarily lose weight on a high-protein/fat diet. It's essentially like the "Atkins" diet. They lose weight because it's all protein and fat, which their metabolisms are generally made for. I would suggest giving your dog a lot of healthy dog-safe carbohydrates such a sweet potatoes, brown rice, apples (as long as the seeds and core have been removed), oatmeal, bananas, certain types of beans (if you don't mind the after effect) and pasta.

I hate to say this, and definitely agree that the dog should be checked for worms, but that's no the only thing to consider.

This could be a tumor. It could be many things. If he's eating the same food the other dogs are, and dropping in weight, than obviously something is going on.

If you have to borrow the money, call the vet and ask for a payment plan, beg, whatever. This dog needs to be seen by a vet. You don't know what you're dealing with here.

By all means, start with the test for worms. If the test comes back positive, get the treatment, see if it works. But, if it's negative, there's more going on, and you need to find the money to give the best care for this animal you willingly took into your life.