Fiber and Weight Loss

Claiming a scientific formulation, fiber supplements, such as Skinny Fiber, have been promoted alongside other fad supplements to promote weight loss in those who take it. Some resellers are even using common exaggerated wording to claim that the product acts like a "magic sponge" to "swallow up fat" and 30%–40% of everything you digest.

Glucomannan

This 'sponge-like' effect most likely comes from the overly-hyped ingredient in Skinny Fiber is glucomannan (amorphophallus konjac), which contains a soluble, fermentable (fermented in colon) fiber taken from an elephant yam, native to Asia. It has been endorsed by many as the 'super-fiber,' because it can reportedly absorb 50% of its weight in water, thus creating a "mass-effect' of a viscous, gel-like mass that forms in the stomach. This gel-like mass eeks its way through the intestines.

Here is a video of what a Skinny Fiber pill does in a glass of water. Clearly, those of us that have made a glass of Metamucil or psyllium husk, we have seen a similar effect.

There is not substantial research evidence that glucomannan is a 'super-fiber', with little to no evidence that it works on weight loss, body mass, body fat, and waist/hip circumference compared to a placebo. 
(see a more recent blog on glucomannan)

Fiber

Beyond glucomannan, Skinny Fiber and other fiber supplements, in and of themselves, are not necessarily bad. Dietary fiber is actually really good, especially in its role in disease and cancer (colon, breast) prevention.

Getting the recommended 20-35 grams of fiber per day aids in digestion, may help control blood sugar and cholesterol, promotes bowel health, helps prevent constipation, and can promote fullness (satiety). Of course, the last two benefits, preventing constipation and promoting fullness, can subsequently lead to weight loss (from more bowel movements and eating less). 

However, in classic supplement industry form, these benefits are attributed to the supplement, and simply not the fiber, and its subsequent effects on bowel movements and caloric intake. They are trying to trick us into selling their specific product.

Understand how Fiber Works

Here is a great illustration of how fiber works. In the end, fiber helps with regularity and slows up food in our stomach, which in turn slows down digestion. So, we do not get a rush of blood cholesterol and sugar into our blood, that we would get without the fiber. Think about eating a donut, the sugar and cholesterol will be in the blood stream quickly, because there is no fiber to slow down the digestion. Now, what if we at a bunch of broccoli, then the donut? Of course, the digestion of the donut would be slowed by the broccoli and its fiber content.

It is hard to sparse out the effect of fiber, because to get fiber, we need to be eating healthy foods (e.g. fruit, vegetables, beans, etc.). I assume most people are not eating fiber supplements with their donut, but could be a new diet trend we can start:  "The Donut and Fiber Diet" or "The Donut and Broccoli Diet".

Read the Label

Looking at the Skinny Fiber label, 2 capsules has 1.16 grams of a proprietary blend of fiber powders, but does not indicate how much fiber is in each capsule (which they should!). Even it was comparable to, let's say, to Fiber Choice chewables, 2 tablets have only a total of 4 grams of fiber. Not much fiber, especially if we are shooting for 30 grams of fiber per day.

Get Fiber in Food, "Dietary Fiber"

So, a fiber supplement gives us about 4 grams of fiber per serving. As a comparison:

Raspberries, 1 cup = 8 grams of fiber
Pear, with skin = 5.5 grams
Apple, with skin = 4.4 grams
Green Peas, 1 cup = 8.8 grams
Broccoli (boiled), 1 cup = 5.1 grams

Clearly, instead of people buying this stuff, they could just eat some fruit and/or vegetables!
Here are some more high fiber foods.