Mark Hyman, MD
Practicing physician and pioneer in functional medicine
May 29, 2010
The Super Fiber That Controls Your Appetite and Blood Sugar
Imagine eating 12 pounds of food a day -- and still staying thin and healthy. That may sound crazy, but it's exactly what our hunter-gatherer ancestors ate for millennia! And they didn't have any obesity or chronic diseases like heart disease, diabetes, cancer, or dementia.
Of course, I wouldn't advise anyone today to eat 12 pounds of food, because the food in our society lacks one major secret ingredient that our ancestors ate in nearly all their food -- fiber!
Fiber has so many health benefits that I want to focus on it in this week's blog. I'll explain some of its benefits and give you nine tips you can begin using today to get more fiber in your diet. I'll also tell you about my favorite "super-fiber" that can help you increase your total fiber intake overnight.
But before I tell you about what fiber can do for you, let's a look a little more at the history of fiber.
Why Bushmen are Healthier than the Average Westerner
Dr. Dennis Burkitt, a famous English physician, studied the differences between indigenous African bushmen and their "civilized" western counterparts. The bushmen seemed to be free of the scourges of modern life -- including heart disease, cancer, diabetes, and obesity.
Dr. Burkitt found that the average bushman had a stool weight of two pounds and the "civilized" men had a stool weight of only four ounces - that's 87.5 percent smaller! The difference was in the amount of fiber they ate.
Today, the average American eats about 8 grams of fiber a day. But the average hunter and gatherer ate 100 grams from all manner of roots, berries, leaves and plant foods. And the fiber is what helped those ancestors of ours stay healthy. Just take a look at all the good things that fiber can do for your body.
You need fiber to keep you healthy from top to bottom, as well as to provide food for the healthy bacteria that work within you to promote health.
In fact, fiber can actually prevent obesity(i) and all the chronic disease of aging. This is because fiber slows the rate at which food enters your bloodstream and increases the speed at which food exits your body through the digestive tract. (ii) That keeps your blood sugar and cholesterol in ideal balance -- and quickly eliminates toxins from your gut and reduces your appetite,
There's good science to back this up. Research shows that fiber can lower blood sugar as much as some diabetes medications,(iii) lower cholesterol(iv), and promote weight loss.(v)
It's clear, fiber is a great ally in the battle of the bulge.
But it's also a hero in more serious battles.
For example, one recent study showed how butyrate made by gut bacteria from certain types of fiber acts as a switching molecule that turns on an anticancer gene -- and turns OFF colon cancer. In fact, fiber has been shown to reduce the risk of colon cancer by as much as a third and breast cancer by almost 40 percent.
It also lowers cholesterol and reduces the risk of heart disease by as much as 40 percent.(vi) And if you have diabetes, adding fiber to your diet may even help you use less insulin. Plus, it's a great natural cure for constipation and irregularity.(vii)
Now that you know how beneficial it is, let's look at how you can begin taking advantage of fiber's health benefits.
Getting Enough Daily Fiber
You should shoot to get 30 to 50 grams of fiber into your diet every day.(viii) The type of fiber you choose is important, too.
Most people think that bran is the best type of fiber to eat. But bran (wheat fiber) is mostly insoluble and doesn't get digested. Think of it as more of a scouring pad for your intestines. That's good for getting you regular, but it just can't help your health the way that soluble fiber can.
You'll find soluble fiber in fruits, vegetables, beans, nuts, seeds and most whole grains. The bacteria in your gut metabolizes the soluble fiber in these foods, and that's when the benefits start.
Soluble fiber can help lower cholesterol, blood sugar, and insulin, prevent cancer, balance hormone levels, remove excess estrogen and reduce the risk of breast cancer, make vitamins and minerals, provide food for the colon cells, and more. So it's easy to see just how crucial soluble fiber is to good heath!
In just a minute, I'm going to tell you how to increase your fiber intake. But first, I want to tell you about some recent discoveries regarding an ancient fiber source that can help you lose weight, lower your cholesterol, reduce your appetite and lower your blood sugar more effectively than ANY other fiber. It's called glucomannan, but I call it super fiber!
Glucomannan: The Benefits of Super Fiber
Glucomannan (GM) is a soluble, fermentable, and highly viscous dietary fiber that comes from the root of the elephant yam, also known as konjac (Amorphophallus konjac or Amorphophallus rivieri), native to Asia. The konjac tuber has been used for centuries as an herbal remedy and to make traditional foods such as konjac jelly, tofu, and noodles. More recently, purified konjac flour, or GM, has been used as a food stabilizer, gelling agent, and supplement.
What makes this fiber so super is the fact that it can absorb up to 50 times its weight in water -- making it one of the most viscous dietary fibers known.
That means that GM can help you shed pounds. In many studies, doses of two to four grams of GM per day were well-tolerated.(ix),(x) This amount also resulted in significant weight loss in overweight and obese individuals.(xi)
GM works by promoting a sense of fullness.(xii),(xiii) Plus, it pushes more calories out through your colon, rather than letting them be absorbed.(xiv) It also lowers the energy density of the food you eat. In other words, it bulks up food in your gut -- creating a lower calorie content per weight of food you eat.(xv)
And since fiber has almost no calories but a lot of weight, adding it to your diet lowers the energy-to-weight ratio of the food that you eat. Studies show that the weight of food controls your appetite, so the fiber increases the food's weight WITHOUT increasing calories -- a critical factor in weight control.
This powerful fiber may also control your appetite in other key ways.
For example, it sends signals to your brain that there is a lot of food in your gut and tells it to slow down on stuffing food in there.
GM also leaves your stomach and small bowel slowly because it is so viscous. By slowing the rate of food absorption from the gut to the bloodstream, GM reduces the amount of insulin produced after a meal, which also controls your appetite.
It may also increase the level of hormones in the gut (such as cholecystokinin), which is another way to control your appetite.(xvi)
And finally, you lose more calories through stool because GM soaks up all those extra calories!
GM can also help your health in other ways. In addition to weight reduction, GM has been studied for its effects on constipation, serum cholesterol,(xvii) blood glucose,(xviii) blood pressure,(xix) and insulin resistance syndrome.(xx)
With all those benefits, there's no doubt you should eat more fiber. No, you probably won't be eating 12 pounds of food like your ancestors did! But you can increase your fiber intake, just by being smart about what you eat. Here are some simple suggestions for increasing fiber in your diet.
9 Tips for Increasing the Fiber in Your Diet
1. Get the flax. Get a coffee grinder just for flax seeds, grind 1/2 cup at a time, and keep it in a tightly sealed glass jar in the fridge or freezer. Eat 2 tablespoons of ground flax seeds a day. Sprinkle it on salads, grains, or vegetable dishes or mix it in a little unsweetened applesauce.
2. Load up on legumes. Beans beat out everything else for fiber content!
3. Bulk up on vegetables. With low levels of calories and high levels of antioxidants and protective phytochemicals, these excellent fiber sources should be heaped on your plate daily.
4. Go with the grain. Whole grains like brown rice or quinoa are rich in fiber, too.
5. Eat more fruit. Include a few servings of low-sugar fruits to your diet daily (berries are the highest in fiber and other protective phytochemicals).
6. Go nuts. Include a few handfuls of almonds, walnuts, pecans, or hazelnuts to your diet every day.
7. Start slowly. Switching abruptly to a high-fiber diet can cause gas and bloating. Increase your fiber intake slowly till you get up to 50 grams a day.
8. Consider a good fiber supplement. If you're have trouble getting your fill of fiber, choose a supplement that contains both soluble and insoluble fiber and no sweeteners or additives.
9. Choose GM. By now, you know that my favorite kind is glucomannan (GM), or konjac. Many companies sell it in capsule form. Although I don't normally recommend specific brands, I like the one produced by Natural Factors called WellBetX. You can take 2 to 4 capsules with a glass of water, 30 to 60 minutes before eating. Don't take any medications within 1 hour before or 2 hours after taking it because the fiber may absorb the medication.
As you can see, fiber has big benefits for your health -- from encouraging weight loss to preventing chronic diseases. I hope you'll start adding more of this important compound into your diet today!
Now I'd like to hear from you ...
Have you noticed any ill-health effects from having a low fiber intake?
How much fiber do you think you currently eat every day?
What high-fiber foods do you enjoy?
What steps are you taking to get more fiber in your diet?
Please let me know your thoughts by adding a comment below.
To your good health,
Mark Hyman, M.D.
(i) Howarth NC, Saltzman E, Roberts SB. Dietary fiber and weight regulation. Nutr Rev. 2001;59:129-139.
(ii) Burton-Freeman B. Dietary fiber and energy regulation. J Nutr. 2000; 130(2S Suppl):272S-275S
(iii) Vuksan V, Sievenpiper SL, Xu Z, et al. Konjac-Mannan and American Ginseng: Emerging alternative therapies for type 2 diabetes mellitus. J Am Coll Nutr. 2001;20(5Suppl):370S-380S.
(iv) Gallaher DD, Gallaher CM, Mahrt GJ, et al. A glucomannan and chitosan fiber supplement decreases plasma cholesterol and increases cholesterol excretion in overweight normocholesterolemic humans. J Am Coll Nutr. 2002;21(5): 428-433.
(v) Baer DJ, Rumpler WV, Miles CW, Fahey GCJ. Dietary fiber decreases the metabolizable energy content and nutrient digestibility of mixed diets fed to humans. J Nutr. 1997;127: 579-586.
(vi) Vuksan V, Jenkins DJ, Spadafora P, et al. Konjac-mannan (glucomannan) improves glycemia and other associated risk factors for coronary heart disease in type 2 diabetes. A randomized controlled metabolic trial. Diabetes Care. 1999;22(6):913-919.
(vii) Astrup A, Vrist E, Quaade F. (1990). Dietary fibre added to a very low calorie diet reduces hunger and alleviates constipation. Int J Obes. 1990;14:105-112.
(viii) Walsh DE, Yaghoubian V, Behforooz A. Effect of glucomannan on obese patients: A clinical study. Int J Obes. 1984;8:289-293.
(ix) Livieri C, Novazi F, Lorini R. The use of highly purified glucomannan-based fibers in childhood obesity. Pediatr Med Chir. 1992;14(2):195-198.
(x)Vita PM, Restelli A, Caspani P, Klinger R. Chronic use of glucomannan in the dietary treatment of severe obesity. Minerva Med. 1992;83(3):135-139.
(xi) Cairella M, Marchini G. Evaluation of the action of glucomannan on metabolic parameters and on the sensation of satiation in overweight and obese patients. ClinTer. 1995;146(4):269-274.
(xii) Burley VJ, Paul AW, Blundell JE. Influence of a high-fibre food (myco-protein) on appetite: Effects on satiation (within meals) and satiety (following meals). Eur J Clin Nutr. 1993;47:409-418.
(xiii) Hill AJ, Blundell JE. Macronutrients and satiety: The effects of a high protein or high carbohydrate meal on subjective motivation to eat and food preferences. Nutr Behav. 1986;3:133-144.
(xiv) Pasman WJ, Saris WH, Wauters MA, Westerterp-Plantenga MS. Effect of one week of fibre supplementation on hunger and satiety ratings and energy intake. Appetite, 1997;29:77-87.
(xv) Liu S, Willett WC, Manson JE, Hu FP, Rosner B, Colditz G. Relation between changes in intakes of dietary fiber and grain products and changes in weight and development of obesity among middle-aged women. Am J Clin Nutr. 2003;78(5):920-927.
(xvi) Bourden I, Yokoyama W, Davis P, et al. Postprandial lipid, glucose, insulin, and cholecystokinin responses in men fed barley pasta enriched with beta-glucan. Am J Clin Nutr. 1999;69:55-63.
(xvii) Arvill A, Bodin L. (1995). Effect of short-term ingestion of konjac glucomannan on serum cholesterol in healthy men. Am J Clin Nutr. 1995;61:585-589.
(xviii) Chen H-L, Sheu WH, Tai T-S, Liaw Y-P, Chen Y-C. Konjac supplement alleviated hypercholesterolemia and hyperglycemia in type 2 diabetic subjects--a randomized double-blind trial. J Am Coll Nutr. 2003;22(1):36-42.
(xix) Reffo GC, Ghirardi PE, Forattini C. Glucomannan in hypertensive outpatients: Pilot clinical trial. Curr Ther Res. 1988; 44(1):22-27.
(xx) Vuksan V, Sievenpiper JL, Owen R, et al. Beneficial effects of viscous dietary fiber from konjac-mannan in subjects with the insulin resistance syndrome: Results of a controlled metabolic trial. Diabetes Care. 2000;23(1):9-14.
Mark Hyman, M.D. practicing physician and founder of The UltraWellness Center is a pioneer in functional medicine. Dr. Hyman is now sharing the 7 ways to tap into your body's natural ability to heal itself. You can follow him on Twitter, connect with him on LinkedIn, watch his videos on Youtube and become a fan on Facebook.