SHEDDING FAT AND STAYING FIT: CAN YOU OVERDOSE ON FIBER?
Some researchers claim that excess fiber may interfere with the absorption of certain nutrients, such as calcium, iron, and zinc. But while several studies have shown that adopting a natural high-fiber regimen causes a small drop in the absorption of certain minerals at first, other research suggests that this effect is only temporary since the body adapts after a few weeks and returns to its previous normal levels. In any case, since natural whole foods are better sources of most vitamins and minerals, a small drop in absorption is of little import.
Phytates (phytic acid), a component of fiber, have often been singled out as the factor responsible for this transient decline, but research by the Nutrition Institute of the U.S. Department of Agriculture has not shown this to be true. Another study, this one performed by Dr. James W. Anderson, chief of endocrinology at the University of Kentucky Medical Center, measured the effects of a diet consisting of 50 to 70 grams of dietary fiber - from vegetables, whole grains, legumes, fruits, and 2/3 cup of oat bran a day - on a group of diabetics for an average of twenty-one months (some were tested for up to fifty-one months). The group did not show any drop in blood levels of calcium, phosphorus, iron, or even magnesium, a mineral in which diabetics may be deficient. In fact, research at a Pritikin Longevity Center showed that people following this type of eating plan for as long as five years had normal levels of vitamins and minerals. In some cases, these levels were higher than in those people consuming a more traditional diet. It appears clear that people who eat even relatively large amounts of dietary fiber remain in a consistent state of mineral balance (that is, they retain as many minerals as they lose), without showing signs of nutritional deficiency.
So, can you overdose on fiber? You can probably take too much as a supplement, just as you can take anything to the point of its not helping you anymore - or even to the point of toxicity. But you will derive optimal benefit by consuming what is provided naturally in the foods recommended on the Pritikin Lifetime Eating Plan: Unless you have certain acute intestinal disorders such as diverticulitis, or an exacerbation of an inflammatory bowel disease such as ulcerative colitis or Crohn's disease, if you're following the Pritikin plan you simply don't have to worry about consuming too much - and you certainly don't have to worry about not getting enough!