Fiber is a nondigestible carbohydrate. We humans hear often about how important a high-fiber diet is, so sometimes people assume the same is true for their pets. Dogs do need some dietary fiber to promote healthy digestion and elimination, but they don't require much. Generally, dog foods advertising themselves as high-fiber are inadvisable. Your dog can experience negative consequences if you feed her too much fiber. Ask your vet about an appropriate amount for your pet.
Effects on Bowel Movements
The primary result of feeding your dog too much fiber is excessive defecation. While most dogs should have one to two bowel movements daily, yours may have considerably more than that, depending on how much excess fiber she eats. Meanwhile, too much fiber without enough water intake can cause constipation, another problem.
Other Negative Effects
Too much fiber and excessive defecation can also prevent proper digestion and absorption of essential nutrients. Different nutritional deficiencies can have all sorts of secondary effects on your pet's health. If your dog is eliminating often and not getting enough nutrients, she'll also eat more. This can cause unhealthy weight gain, which also leads to complications down the road, such as diabetes, arthritis and heart problems.