My dogs occasionally eat grass. They won't tell me why but perhaps they need the fiber. The act of eating indigestible things is known as pica. Some children have eaten calk, dirt, sand, or paper. If you eat anything processed for more than one month then you might qualify for the diagnosis of xylophagia (the consumption of wood) in the form of cellulose. Just look on the nutritional facts for some cheap products like hotdogs. How in the world does a hotdog have fiber? The same may be true for things like shredded cheese, ice cream and salad dressings.
While I would prefer to avoid eating trees, it may surprise you that the consumption of cellulose is not a bad thing. Methylcellulose is a soluble fiber product available as EZ Fiber (from bamboo cellulose). There are other well know commercial fiber products that use methylcellulose; however, they contain additives and artificial sweeteners. They may also contain maltodextrin which can be made from wheat and contain gluten.
Because of its thickening properties, cellulose is used in some sustained release prescription products. While the food additive cellulose has no nutritional value the fiber content is needed in our Standard American Diet.
When you eat unprocessed foods there are parts that are not digested. The cellulose in corn is evidently not digested. Fiber is a natural part of foods known to be good for you and may be either soluble fiber, insoluble fiber or a combination. Soluble fiber such as the (EZ Fiber) turns to a gel, slows digestion and absorbs bile and toxins in the gut. Insoluble fiber found in carrots, celery, green beans, and green leafy vegetables adds bulk to the stool and may help food pass more quickly.
Adequate fiber helps control blood sugar, and can decrease your risk of heart disease and stroke. It is also useful in diverticulitis, irritable bowel syndrome, and hemorrhoids. The fiber goal is 20 to 30 grams of fiber per day. Healthy choices include chia seeds, psyllium and ground flax seeds. Fiber PF is a product with a combination of psyllium and flax seeds. It also contains nutrients to aid in healing the intestinal tract. Fiber rich vegetables include root vegetables, beans, peas, broccoli, brussel sprouts, cabbage, and cauliflower. Fibrous fruits are also helpful.