Welcome! My name isXXXXX am a 2003 graduate from UC Davis, and currently a Medical Director of a veterinary hospital.
Difficult question. I agree with you that not all foods are really created equal. Actually, neither are the pets. Let's take a very active or hyper labrador or shephered, compared to the same dog that sits around in a house all day doing nothing. Their energy "needs" the calories they need to maintain their body weights are very different.
I reviewed the previous answer and your responses. Many of these holistic diets are not necessary.
You want something researched. Agreed. Then, let's stick with a food that is clinically tested.
Science Diet foods, also known as Hills, is widely respected in the veterinary community. Some people hate it because it has corn, or meat is not the first ingredient. I can understand that. But!!!!
They have a new product line. It is called Science Diet "Ideal Balance". It does not have corn, uses quality meat products, and it is very well balanced.
Ironically, you'll still likely pay less for Ideal Balance, then you would Blue Buffalo, or these fancy holistic foods.
How much to feed. Guess what. As much as you want!!!!
What? That's crazy.
Yep. You need to weight Ruben once a month and work with your vet.
Your vet should evaluate her and establish her current body score, as to determine how much underweight she may be.
But, if we determine 2 cups a day is what she needs to maintain and gain just a bit, than its 2 cups. if it happens to be 4 or 5 cups, than that's the number.
Don't worry about the guidelines on the bag!! It is only a starting guideline, but please, work with your vet to keep assessing her weight regularly. Too fast of growth is not ideal either for the bone structure. Ideal Balance by Hill's
One last thing:
Make sure a fecal test has been done. Even if it was alredy done, I would encourage repeating one more time.
Bring in a fresh poop sample to the veterinarian. Ideally, within a few hours. Request that it be sent “OUT” to the laboratory instead of being looked at in the hospital (more accurate that way). We are not interested in only worm eggs, but also checking for the very common microscopic bugs like giardia and coccidia. These types of parasites will not be cured with over-the-counter dewormers. Giardia can also be difficult to identify on routine fecal tests, so ask your vet if they always add a “giardia elisa” to the fecal test. Here is more detailed information about fecal testing:Fecal Testing
I would hate for something as silly as a giardia infection to be the cause of poor weight gain, even if there is no diarrhea.
Hope that information has been helpful.
Please remember to select Reply to Expert, if for any reason you need further clarification, have more questions, or were expecting a different type of answer. Prior to leaving a feedback rating, which I greatly appreciate, my goal is to provide you the best answer possible.