Fiber is good. Don't know what is in metamucil -- could have other "stimulants" which wouldn't be good. I prefer to eat whole foods, rather than take supplements.
Consider adding a couple tablespoons of ground flax seed to your breakfast and another couple to you dinner. This offers good fiber, good (omega-3) fats, good protein and lots of vitamins and minerals.
Pale stools imply a lack of bile. Bile turns the stool dark brown. A common reason for "clay colored stools" is gallbladder obstruction. Do you have trouble digesting rich foods?
You might start eating lots of fresh whole apples in preparation for a liver flush. That will provide both malic acid to soften Gallstones
and give you more fiber from a nourishing whole food source. Four apples per day gives you 50% of the day's supply of fiber!
There are two main types of fiber: Soluble and insoluble.
Soluble fiber is stuff that thickens liquids, like oat bran, pectin, etc. Apple flesh has lots of pectin. Soluble fiber absorbs liquids, mops up toxins and cholesterol in the intestines, and forms soft stools. If one has diarrhea, soluble fiber forms bowel movements. If one has small hard stools, soluble fiber enlarges and softens them.
Insoluble fiber is stuff we can't digest. Cellulose, wheat bran, psyllium husk, etc. Apple skin has lots of insoluble fiber. Insoluble fiber adds bulk, speeds the passage of food through the intestines and "brushes" the intestines clean.