When I was a kid, my grandmother was always trying to get me to eat a lot foods you had to chew a lot. “Gives you roughage,” she’d say wisely. “Keeps you regular.”
Well, that was then, this is now.
Our prune-eating grandmothers were onto something, but they had just scratched the tip of the iceberg. Research on fiber is exploding, and its résumé of health benefits now extends to weight loss, as well as cancer, diabetes, heart disease, blood sugar management. Fiber is essential to the care and feeding of a healthy microbiome.
What’s more, the old conventional wis-dom about there being only two kinds of fiber (“soluble” and “insoluble”) was upended in the 1980s when two English researchers—Englyst and Cummings — discovered a third kind of fiber called resistant starch which, as of this writing, is currently the subject of an enormous amount of research interest. (More on this in the next column.)
So what is fiber? What does it do? Why do we need it? And why should we care? Let’s start with weight loss.
Fiber’s not expensive, it’s not exotic, and it’s certainly not sexy, but when it comes to weight loss, it works like a charm. More than a dozen clinical studies have used dietary fiber supplements for weight loss, most with positive outcomes. When you take the fiber supplement with water before meals, the water-soluble fiber binds to water in the stomach, making you feel full and less likely to overeat. It also suppresses hunger.
Fiber supplements have also been shown to enhance blood sugar control and insulin effects. It has even been shown to reduce the number of calories that the body absorbs — adding up to about 3 to 18 pounds a year. And a study in the prestigious New England Journal of Medicine found that a diet with 50 grams of fiber today lowered insulin levels in the blood. For the record, insulin’s two common nicknames among health professionals are “the hunger hormone” and “the fat-storing hormone.”
My co-author on the book, Smart Fat — Steven Masley, M.D. — followed patients at his south Florida clinic for ten years, tracking what they ate, how much exercise they did, what vitamins they took, and how much weight they lost. He found that fiber intake was one of three variables that predicted weight loss success better than anything else (The other two were minutes spent exercising and vitamin D intake).
One of the most impressive studies of all followed 2,900 healthy subjects for ten years and looked at the relationship between fiber, cardio-vascular disease, weight, and insulin. The results were spectacular. Fiber was inversely associated with insulin levels and weight, and low fiber intake turned out to be a better predictor of heart disease than saturated-fat consumption (not surprising to anyone who’s read my book, The Great Cholesterol Myth).
Remember, the benefits of fiber aren’t limited to weight loss. Fiber is the great modifier of blood sugar, and high blood sugar has been implicated in a baker’s dozen of unwanted degenerative disease, including heart disease. Even Alzheimer’s is now being called “type 3 diabetes”.
Americans currently get a paltry amount of fiber in their diets, estimated at around 10 to 11 grams per day. That’s not nearly enough. I don’t usually agree with conventional recommendations from traditional health agencies, but in this case, they’re on the right track: Current recommendations range from 25 to 38 grams a day (depending on age and sex), but in my opinion more is even better. Our caveman ancestors got much more — between 50 and 100 grams daily, according to most research.
In the next column, we’ll talk about what fiber is, where it’s found, and how to get more of it in your diet.