Directions: 2 to 5 capsules up to 4 times daily for fiber supplementation. (metamucil.com)
In my experience, I can say that most people do need an extra fiber supplementation to their everyday diet - no matter if they are on keto or not. (bodyketosis.com)
The Journal of Nutrition 146, no. 2 (2016): 306 - 317; Thompson, S. V., et al. «Effects of isolated soluble fiber supplementation on body weight, glycemia, and insulinemia in adults with overweight and obesity: A systematic review and meta - analysis of randomized controlled trials.» (saragottfriedmd.com)