Psyllium is a water-soluble complex carbohydrate. This article seeks truth concerning weight loss on dietary fiber.
Non-peer-reviewed articles concerning weight loss on psyllium are common.
Practicing medicine requires evidence-based information winnowing chaff from seed.
This article explores peer-reviewed reports concerning the effect of fiber on body mass, where soluble and insoluble fiber are studied together. Bogus science would not withstand peer review found in this research.
Fiber sources abound in markets and home gardens. Leaving aisles of simple sugary foods, one is immersed in fresh produce displays, displaying gems rich in complex carbohydrate.
A pure form of fiber--psyllium--is readily available, reaped from milled seed husks of Plantago ovata, a species of plantain cultivated in India. Taking psyllium husk powder orally, mixed in water, creates a mucilage, expanding and pressing on chains of intestinal neurons, creating a "full feeling" and satiety, resulting in reduced food intake, and more weight loss.
Hypotheses concerning the biophysiological mechanism of fibre-induced weight loss must be supported scientifically. Extant medical research supports the effectiveness of psyllium and other fiber sources in obesity management:
• "Psyllium and chitosan rely on their bulk formation to decrease hunger and fat absorption, respectively." 
• "Individuals on a diet with a below median fat intake and an above median fiber intake showed a weight loss of 3.1 kg vs 0.7 kg for those on a diet with an above median fat intake. The below median fat intake and above median fiber intake reduced the incidence of diabetes in this patient group by at least 50%." 
• "...During this 6 week period all food was provided and adherence was high irrespective of the fiber randomization group. In the subsequent 9 month period when fiber intake was voluntary (and for most of this time subjects self-prepared their regimen), those who continued consuming high levels of dietary fiber sustained significantly greater levels of CR [calorie restriction], equilibrated at a lower BMI, and experienced greater dietary satisfaction than subjects who ate less dietary fiber." 
• "Low-fat and VLF diets contain a high proportion of complex CHOs, fruits, and vegetables. They are naturally high in fiber and low in caloric density. Individuals consuming these types of diets consume fewer calories and lose weight (13-17)...
• "Most participants increased consumption of vegetable products, but the increase in dietary fibre exhibited wide between-subject variability (6-65 g/day). Body weight, waist circumference, and mean systolic and diastolic blood pressure decreased across quintiles of fibre intake." "Conclusions: Increasing dietary fibre intake with natural foods is associated with reductions in classical and novel cardiovascular risk factors in a high-risk cohort." 
• "After adjustment for potential confounding factors,dietary fiber showed linear associations from lowest to highest quintiles of intake with body weight and waist-to-hip ratio. Fiber was also [negatively] associated with blood pressure and levels of triglyceride, [positively associated with] high-density lipoprotein cholesterol, 
This review of peer-reviewed medical articles supports hope in a helpful effect from increased dietary fiber on human body mass. The fiber sources studied included fresh produce from stores or home gardens, cereal fiber (insoluble or soluble), psyllium powder, such as is found in Metamucil, and other bulking forms.
 American Journal of Health-System Pharmacy. 09/01/2001;2001;58(17).
 Diabetologia 49: 912-920 
 Aging Clinical Experimental Research. Feb. 10, 2008;20:513-520.
 Obesity Research. (2001) 9, 1S-5S E-mail: email@example.com
 J Epidemiol Community Health 2009;63:582-588.
 JAMA. 1999;282:1539-1546.