Fiber (soluble / psyllium)
What it is
Viscous, gel-forming soluble fiber that slows digestion and increases satiety to support lower energy intake.
What the evidence says
Evidence is mixed and effects are small. A 2023 meta-analysis in the American Journal of Clinical Nutrition found isolated soluble fiber produced only minor weight changes in adults with overweight/obesity, while a dose-response meta-analysis of psyllium specifically found no significant effect on body weight, BMI or waist circumference. Soluble fiber more reliably improves glycemia and lipids than it drives weight loss, so its role is supportive (satiety, metabolic health) rather than a primary slimming agent.
Roughly 5-15 g/day of psyllium (often divided before meals); general soluble-fiber intake of 10 g+/day in trials.
Educational summary of doses studied — not a recommendation. Talk to a clinician before starting any supplement.
Sources (2)
- 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 — American Journal of Clinical Nutrition (2023)
- The effects of psyllium supplementation on body weight, body mass index and waist circumference in adults: A systematic review and dose-response meta-analysis of randomized controlled trials — Critical Reviews in Food Science and Nutrition (2020)
Educational summary of published research, checked against primary sources and linked inline. Not medical advice; supplements are not FDA-evaluated to treat disease. See our editorial policy.