Confused about dietary fiber? No wonder.

I always thought fiber had a simple definition: complex carbohydrates in food plants impervious to enzymes in our digestive tract.

OK, bacterial enzymes complicate the definition a bit.   But the real complication comes from what food companies toss into products to increase their apparent fiber content on food labels.

Now the FDA has issued guidance to industry about what companies can use to boost their products’ fiber content.  In FDA-speak:

We intend to exercise enforcement discretion for the declaration of dietary fiber, pending completion of a rulemaking regarding revising our regulations, if the declaration includes one or more of the following eight isolated or synthetic non-digestible carbohydrates, when present in a food and included in the amount of dietary fiber declared on the Nutrition or Supplement Facts label:

• mixed plant cell wall fibers
• arabinoxylan
• alginate
• inulin and inulin-type fructans
• high amylose starch (resistant starch)
• galactooligosaccharide
• polydextrose
• resistant maltodextrin/dextrin

What this means is that food manufacturers can use these to count as fiber.

Here, for example, is a happy announcement from Sensus, a company that manufactures “Frutafit” and “Frutalose” chicory root fibers.  It

welcomes the announcement that the US Food and Drug Administration (FDA) recognizes inulin-type fructans derived from chicory root as dietary fiber for the new nutrition facts label. The recognition consolidates the fiber status of chicory root fiber in the US and supports further opportunities for healthy food applications in the US.

The Sensus announcement explains that this decision came about as a result of a “joint citizen petition,” one in which you can bet this company was involved.

This decision is about marketing.

If you want fiber in your diet, the best sources are still foods: fruits, vegetables, beans, whole grains, nuts.