Fiber seems so, well, boring. It's not one of the nutrition topics commonly placed among

cutting-edge research. By definition, fiber is indigestible, can't be absorbed into the body,

so it just stays in our gut to bulk up our stool.

This is not to belittle the importance of bowel regularity. Constipation is a global issue.

In the United States, for example, chronic idiopathic constipation impacts 5% of people.

If even half of the adult U.S. population ate three more grams of fiber a day,

a quarter cup of cooked beans or a bowl of oatmeal, we could relieve enough constipation to save

billions of dollars in medical costs annually. But it's not like we thought fiber really did

anything. In fact, you can get the same laxative effect with indigestible plastic particles.

Feeding people a couple spoonfuls of sliced polyvinyl tubing, not recommended, ends up

increasing their stool bulk, frequency, and softening the consistency. So for decades, fiber was

viewed as a similarly inert, indigestible substance.

We've since moved beyond fiber's classic function as an anti-constipation agent

to recognizing its other beneficial effects, including the many ways it can facilitate weight loss.

The first major review, dietary fiber and weight regulation, based on a dozen interventional

studies where people were randomized into higher or lower fiber diets, found that the

additional consumption of 14 grams of fiber a day led to an average weight loss of four pounds,

over 3.8 months. That's only about a pound a month, but the weight loss was greater among

those with excess weight.

Study participants with overweight or obesity lost triple the weight compared to lean individuals.

And 14 grams of fiber isn't a lot.

That would even take the average U.S. diet up to the recommended minimum average adequate

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