Most people understand the importance of dietary fiber in their diet. Much has been said about its importance in heart health, diabetes, cancer prevention, and even weight control.
What is less well understood is how different types of fiber effect the body. Some provide fecal bulk, some are absorbed more quickly into the blood stream than others, and thus raise blood sugar levels more quickly, and yet others provide benefits to the heart.
Thus, despite the apparent simplicity, fiber is a complex topic. And whilst all types of fiber are important, if you are looking at preventing or managing specific conditions, its not enough to just look at the total dietary fiber as written on food packaging.
Dietary fiber is broadly classified into soluble and insoluble fiber. Soluble fiber is fermented in the colon, and plays a role in slowing the absorption of glucose into the bloodstream. It also encourages the growth of the 'friendly' bacteria that help break down bile, and are involved in the creation of B vitamins like folic acid, niacin, and pyridoxine.
Insoluble fiber, on the other hand, acts a bit like an intestinal broom. It provides bulk to the stools, and makes sure they pass through easily and quickly. This is the type of fiber that keeps you 'regular', not insoluble fiber.
Insoluble fiber does provide a feeling of fullness, however. This makes it great for weight loss and controlling hunger. It also keeps blood sugar levels more stable, although research into the rate at which carbohydrates enter the bloodstream have found there to be some significant differences within the foods that make up the fiber group. Dietary fiber can thus be rated by its Glycemic Index, which effectively ranks fiber foods with each other on a relative scale.
The idea is to try and include more low gylcemic index foods. Foods with a high glycemic index cause blood sugar levels to spike, providing too much energy to the blood in the form of carbohydrates, which in turn sets off the body's sugar controlling hormone - insulin. You thus get a 'high' followed by a sudden drop. This in turn leads the body to want more carbohydrates to balance itself again, leading to cravings and overeating, as well as tiredness and moodiness.
Low glycemic index foods include lentils, chickpeas, baked beans, fruit loaf, salmon sushi, barley, milk, custard, soy milk, yoghurt (not diet yoghurt), apples, strawberries, grapes, spaghetti, peas, carrots, fructose, strawberry jam, and chocolate milk.
Moderate glycemic index foods include pea soup, rye bread, porridge, muesli, ice cream, bananas, pineapple, kiwi fruit, new potatoes, beetroot, white sugar, honey, and mars bars.
High glycemic index foods include broad beans, bagels, white bread, brown rice, watermelon, udon noodles, desiree, pontiac and sebago potatoes, and glucose.
For riders following XLR8 make sure you check the carbs in all foods before consuming some great options for food with fibre are:
100 grams of asparagus has 2.1 grams of dietary fiber and 3.38 grams of carbohydrates.
Asparagus grows perennially, peaking in mid-spring to early summer. The stalk is very fibrous. It is delicious when cooked just until tender by lightly steaming, oven roasting, or grilling with a little olive oil. The flavor of asparagus is unique and pairs well with heavier proteins and mashes. It is a good source of vitamin A and copper.
2. Bok Choy
100 grams of Bok Choy has 1 gram of fiber and 2.18 grams of carbohydrates.
Bok Choy is a sturdy cruciferous vegetable with a crunchy base and broad leaves that lends itself well to Asian stir fry dishes. It is a great source of vitamins A, C, and K, carotenes, and antioxidants. Antioxidants fight the damaging free radicals that contribute to premature aging and disease.
3. Broccoli Rabe
100 grams of broccoli rabe has 2.7 grams of fiber and 2.85 grams of carbohydrates.
This bitter, leafy and flowering vegetable can be steamed or sautéed, and seasoned with garlic and lemon to quell the bitterness. Broccoli rabe is a great source of minerals, such as calcium, iron, and magnesium.
100 grams of radishes has 1.6 grams of dietary fiber 3.4 grams of carbohydrates.
Crisp radish bulbs and the greens are both delicious eaten raw in salads. They are both spicy and cooling. Radishes contain sulforaphane, an antioxidant which is known to aid in the prevention of various types of cancer.
100 grams of spinach leaves has 2.2 grams of dietary fiber and 3.63 grams of carbohydrates.
Spinach is a dark leafy green. It can be eaten raw in salads, sautéed, or added to soups and stews. Spinach is quite high in vitamin A. It is also a great source of calcium, required for bone health, and iron, needed blood health.
6. Swiss Chard
100 grams of Swiss chard has 1.6 grams of dietary fiber and 3.74 grams of carbohydrates.
Swiss chard is another dark green leafy vegetable with a colorful, edible, and fibrous stalk or rib. It is a wonderful source of vitamin K. It can eaten raw, sautéed with garlic and olive oil, or braised. You can also pickle the crunchy ribs.
100 grams of zucchini has 1 gram of fiber and 3.11 grams of carbohydrates.
Green and yellow zucchini, also known as summer squash or courgettes, contains no saturated fat or cholesterol. Zucchini is an important source of potassium. It can be sautéed, grilled, or stuffed and baked. It is a favorite in the Mediterranean Diet.
100 grams of avocado has 6.7 grams of dietary fiber and 8.53 grams of carbohydrates.
Avocados are loaded with fiber. The flesh of this unique fruit is creamy, fatty, and savory. Avocados are one of the best sources of mono-unsaturated fatty acids that are vital to lowering LDL cholesterol. The flesh is best enjoyed raw on salads, in guacamole, or as a creamy element blended into smoothies. You can also use it as a sandwich spread in place of mayonnaise or mustard.
100 grams of blackberries has 5.3 grams of dietary fiber and 9.61 grams of carbohydrates.
Blackberries are best eaten at their peak of ripeness. Eaten too soon will result in a terribly tart sensation. Eaten too late they will be mushy. You can use them in pies, jams, fruit salads, and berry compote sauces. Or, just toss them whole on yogurt or ice cream. They are a great source of both soluble and insoluble fiber, which is beneficial to digestion. They are also a decent supply of copper.
100 grams of gooseberries has 4.3 grams of dietary fiber and 10.18 grams of carbohydrates.
Gooseberries are not always available in markets. They thrive in humid summers and severe winters. Perhaps that is why they seem prevalent in Northern European climate zones. They are available in a variety of colors. Gooseberries are high in anthocyanins and flavones, the compounds that are responsible for fighting aging, cancer, and inflammation. The tart berries are used to add flavor to cooked, savory, protein dishes. The ripe berries are generally eaten by the handful.
100 grams of mulberries has 1.7 grams of dietary fiber and 9.8 grams of carbohydrates.
Wild mulberries are native to North America and Asia. They are very similar in structure to blackberries. In fact, mulberries are prepared in the same manner. Resveratrol is one of the key components in mulberries, similar to red grapes. Resveratrol reduces constriction of the blood vessels, thereby lowering blood pressure and preventing stroke.
100 grams of nectarines has 1.7 grams of dietary fiber and 10.55 grams of carbohydrates.
Nectarines are a stone fruit that is similar to a peach in texture and flavor. They have a smooth skin, rather than the fuzzy skin a peach has. Nectarines have a floral aroma. The best way to eat them is right off the tree when they are ripe, just like an apple. The skin and flesh are edible, not the stone. This is a great source of vitamins A and E, as well as the B vitamins.
100 grams of peaches has 1.5 grams of dietary fiber and 9.54 grams of carbohydrates.
Peaches are perfect for pies and cobblers, or cooked into chutneys. You can braise tough cuts of pork with sweet peaches, or make a barbeque sauce from them. The best way to eat a peach is to grab it fresh off the tree with plenty of napkins to catch the ripe, sweet juice. Peaches are lower in sugar than you might think. They are also a good source of vitamins and beta-carotene.
100 grams of strawberries has 2 grams of dietary fiber and 7.7 grams of carbohydrates.
Strawberries are sweet and tart, seeds and all. You can easily just eat them with your fingers, dip them in warm dark chocolate or honey and yogurt, or blend them into smoothies. Fresh berries are rich in vitamin C, a powerful antioxidant. Strawberries are low in calories and relatively low in carbs for a fruit.
15. Star Fruit
100 grams of star fruit has 2.8 grams of dietary fiber and 6.73 grams of carbohydrates.
Star fruit is one of the lowest carbohydrate fruits. The firm skin of the fruit is a good source of dietary fiber and is just as edible as the flesh. This fruit is both sweet and tart. It is great all by itself, mixed into fruit salad, used as a garnish, or even pickled. Star fruit contains quercetin, an important flavonoid that is beneficial to cardiovascular health and has been shown to be helpful with seasonal allergies.
100 grams of tomatoes has 1.2 grams of dietary fiber and 3.9 grams of carbohydrates.
While technically a fruit, tomatoes are mostly used in savory recipes. They can be eaten raw or cooked. Tomatoes are typically the base for sauces in Italian and Mexican cuisines. They are a rich source of lycopene, a flavonoid antioxidant. Lycopene may help protect cells and other structures in the human body from harmful free radicals.
Seeds and Bran
17. Chia Seeds
1 tablespoon of chia seeds has approximately 5.2 grams of dietary fiber and 6 grams of carbohydrates.
Chia seeds are native to Mexico, Central America, and South America. These little seeds are calorie dense, but those are mostly from polyunsaturated fatty acids. They are rich in omega 3s, antioxidants, and dietary fiber. Chias are also loaded with calcium and phosphorous. When the seeds come in contact with water they turn to a gel, making them a great thickener for smoothies. They also add plant based protein to any dish.
18. Flax Seeds
1 tablespoon of ground flax seeds has approximately 2.8 grams of dietary fiber and 3 grams of carbohydrates.
Flax seeds are a super food that has both soluble and insoluble fiber. They are also really low in carbohydrates. Flax seeds will expand in the presence of liquid. That is why they are used in place of eggs as a binder in vegan dishes. Flax seeds are rich in omega 3 fatty acids – the good fats for heart health. They are also an excellent source of vitamin E. Like chia, flax is a good source of plant based protein. These seeds are used in baking or sprinkled raw on cereals and soups. A little goes a long way.
19. Pumpkin Seeds
100 grams of pumpkin seeds has 6 grams of dietary fiber and 10.71 grams of carbohydrates.
Pumpkin seeds are pretty amazing. When chewed raw, they are reported to expel parasites and worms from the intestines. These seeds contain glutamate and tryptophan. Both nutrients are essential for mood enhancement and sleep regulation. Pumpkin seeds have a mild flavor when eaten raw. They are often toasted or coated in salt to eat as a snack.
20. Rice Bran
1 tablespoon of rice bran has 1.5 grams of dietary fiber and 3.7 grams of carbohydrates.
Rice bran is the outer layer of brown rice that is removed in order to make polished white rice. Bran helps in the reduction of cholesterol because it contains the antioxidant gamma-oryzanol. Bran also helps with bowel regularity. It can be added to baked goods or sprinkled on a bowl of yogurt or fruit. It has a slightly nutty flavor.
21. Wheat Bran
1 tablespoon of wheat bran has 1.6 grams of dietary fiber and 2.3 grams of carbohydrates.
Wheat bran is the outer shell if the wheat plant that is removed in the processing of wheat into flour. It is known for its high fiber content and eaten primarily for its gut motility benefits. Wheat bran helps in the prevention of cancers of the gastrointestinal tract. It is also a good source of niacin, vitamin B6, and iron. Wheat bran can be used in baked goods or added raw to smoothies or yogurt.
We need both soluble and insoluble fiber, however. A study published in the American Journal of Clinical Nutrition found that in a group of 6000 French men and women, those with the highest levels of soluble and insoluble fiber in their diet had a lower risk of being overweight, a lower risk of having blood pressure problems, cholesterol problems, and they had better levels of triacylglycerols and homocysteine. The last two are measure3 of heart health.
Fiber from cereals was linked to lower body fat, lower blood pressure, and lower levels of homocysteine. Those with a higher intake of vegetables, also a source of fiber, had lower blood pressure and lower homocysteine levels. Fiber from fresh fruit was associated with a lower waist to hip ratio, and lower blood pressure. And fiber from dried fruit, nuts, and seeds (like sesame seeds, sunflower seeds, and pumpkin seeds) was also linked to a lower waist to hip ratio, lower body fat, and a better fasting glucose concentration. Fasting glucose relates to having a steady level of glucose between meals. If it dips too low, we crave things, often sweets.
Fiber has another interesting benefit. In people with type 2 diabetes, it has been found to lower the levels of 'bad' cholesterol, and increase the levels of 'good' cholesterol. It has already been established that fiber supplements will lower the levels of bad cholesterol in people, whether they have diabetes or not. But this new study found that fiber supplements also decreased the reabsorption of cholesterol from meals.
To get this benefit, it is important to time taking the fiber supplement in synch with meals. The study participants took a fiber supplement drink before mealtimes, and this ensured that the fiber was in the intestines when the meal was being eaten. The people in the study participated for 90 days and their average age was 59 years old.
1. Australian Healthy Food, November 2005