I believe that Dr. Tobias is one of the leading experts on MVD, and she says:
There is no surgical treatment for HMD. Dogs with the condition are managed medically, and treatment is based on the severity of the condition. In some dogs no treatment is needed. The mainstay of medical management is to reduce the amount of protein in the diet. Specific veterinary diets such as Hill’s L/d have been formulated for dogs with liver disease.
The protein is highly digestible (often milk based or soy) and is only mildly protein restricted. Diets for dogs with HMD should contain about 15-20% protein (roughly 2 g/kg per day of protein), 15-30% fat, and 30-50% highly digestible carbohydrates on a dry matter basis. They should also be high in zinc and Vitamin E and low in manganese. Most dogs with HMD do well on diet change alone.
Changing the type of bacteria that live in the intestines can also decrease toxin production and absorption. This can be accomplished by giving lactulose syrup or yogurt. Some veterinarians may prescribe antibiotics for a short time as well.
Nutriceuticals- compounds that are not considered “drugs”- can also improve liver function. Milk thistle (“silymarin”) can help improve liver function and regeneration. Because the government does not regulate over-the-counter compounds, purchase of specially formulated veterinary supplements is recommended. Two veterinary companies that sell milk thistle include Nutrimax (“Marin”) and RxVitamins (“Hepatosupport”). Veterinarians may also prescribe Denosyl (SAM-e) to improve liver function.
MVD
I'm not sure, but it seems like some of the answers you are getting is just talking about the amount of protein in a normal dog's diet.