Real talk: Technically, fiber is not considered an essential nutrient for dogs—they can live without it. (You know, in the same way you can technically live without your iPhone.) That said, incorporating it into your dog's diet has quite a few health benefits both in both the short and long-term. But a quick scan for "fiber" on the dog food label isn't enough: It's important to understand the different types and how they could help or harm your pup's overall health.
Broadly defined, fiber is the part of grains and vegetables that doesn't become absorbed through digestion. Soluble fiber absorbs water and is fermented in the intestines, releasing fatty acids that promote the health of the lining of the gut. Insoluble fiber also absorbs water, but doesn't ferment. Most fiber-rich foods contain a mix of both soluble and insoluble fiber, both of which offer benefits.
For starters, fiber is the ideal remedy for dogs who suffer from both diarrhea and constipation because insoluble fiber acts like a sponge by absorbing excess water and acid (aka diarrhea) and soluble fiber acts like a broom, sweeping things along and preventing roadblocks (aka constipation). Similarly, it's a go-to solution for dogs who need to drop a few pounds. Typically low in calories, fiber absorbs water and creates a sensation of being fuller, longer.
The long-term perks? The same fiber that promotes a regular poop cycle will help keep the cells and bacteria in your pup's colon healthy. And the same fiber that helps your dog reach and maintain a healthy weight and can help dogs with blood sugar problems, including diabetes.
Just in case you are inclined to dismiss fiber or switch to a fiber-heavy doggy diet, there are issues with too little and too much. Aside from diarrhea and constipation, not enough fiber in a dog's diet can lead to troubles like blocked anal glands and long-term health issues regarding colon diseases and weight, which in turn lead to myriad chronic health problems that affect your pet's quality of life.
On the other hand, too much fiber causes food to move through the dog's digestive system too quickly, keeping the body from absorbing essential nutrients from their food. Something else to keep in mind if you're using fiber to regulate your dog's weight: dropping pounds too fast could lead to unintended problems.
How to Find the Balance
Start by reading labels. Look for fiber-rich ingredients like vegetables and grains and avoid those listing "powdered cellulose," which is a blanket term for subpar ingredients that literally could include shredded paper, tree pulp and cotton. These are cheap, starchy fillers that offer virtually no nutritional benefit.
Next, evaluate your dog—if he is healthy, active, poops regularly and is at an ideal weight, he's likely getting an adequate amount of fiber. (That doesn't mean he wouldn't enjoy and benefit from a few green peas in his dog bowl!) However, if your dog is having trouble with digestion or weight, it could be that their fiber intake isn't ideal. Talk with your vet about either changing your dog's diet or supplementing it with fresh vegetables like kale, pumpkin, apples, peas, broccoli, celery, and beets.