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Dietary Fiber –
An Essential Ally
in Weight Management
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Many of the health
benefits of dietary fibre have been known for over one hundred
years; dietary fibre prevents constipation; lowers blood
cholesterol levels; stabilizes blood sugar levels, plays a role
in the prevention and treatment of diverticular disease; and
protects against large bowel cancer. More recently the very
important role that foods high in dietary fibre can play in
regulating body weight has also become apparent. It’s no wonder
then, that the WHO, in its report on the Global Strategy on
Diet, Physical Activity and Health, is recommending increasing
fibre intake, in conjunction with a low-fat diet and regular
physical activity to fight the overweight and obesity battle.
What evidence is there that dietary fibre really can help in
regulating body weight ?
Numerous studies have led experts to more fully understand the
vital role that dietary fibre can play in the prevention of
weight gain and promoting weight loss:
• A team of researchers lead by Dr. David S. Ludwig of the
Children’s Hospital in Boston, Massachusetts examined the diets
of over 2,900 individuals between 18 and 30 years of age and
found that at all levels of fat intake, individuals who ate at
least 21 grams of fibre per day gained, on average, eight pounds
or 3.6 kilograms less over the 10-year period than those who ate
the least amount of fibre.
• In another 12-year study, Dr. Liu and his colleagues from the
Harvard School of Public Health looked at the intake of grain
products in 74,091 nurses. They found that women with the
greatest whole grain consumption weighed less AND were less
likely to gain weight and become obese.
• A study of 2909 young adult males, by Pereira and Ludwig also
found that a higher dietary fiber intake was associated with
lower body weight; lower blood pressure; better blood glucose
control; lower low-density (bad) cholesterol and higher (good)
high-density cholesterol levels. Reviews of randomized trials by
Pereira and Ludwig have also found that a high intake of dietary
fibre promotes weight loss.
• Howard, Saltzman & Robert reviewed 11 studies in which amount
of food eaten was not restricted,, and found a mean weight loss
of 1.9 kg over 3.8 months with increased fibre intake.
How does dietary fibre act on the body to promote weight
management ?
Researchers believe that the beneficial effect of fibre in
weight regulation, is due to the fact that
• High fibre foods generally require more chewing time – this
gives the body time to register when appetite is satisfied and
to stop eating, thus reducing the risk of over-consumption.
• High fibre foods linger in the stomach longer - so the
sensation of fullness is sustained for longer.
• High fibre foods tend to be less "energy dense" - offering
fewer calories for the same volume of food.
• Ludwig and colleagues also believe that fibre’s ability to
reduce insulin secretion and hence fat deposition may play a
role in the prevention of weight gain.
How much dietary fibre is required to gain the benefits ?
In September 2002, the U.S. National Academies of Science
reviewed the daily recommendations for dietary fibre. The
revised recommendations were 38 grams for men and 25 grams daily
for women 50 years and younger; and 30 and 21 grams per day,
respectively, for men and women over 50 (older people tend to
eat less food and energy and thus recommendations are adjusted
accordingly).
The recommendation for children older than 2 years is to
increase dietary fiber intake to an amount equal to or greater
than their age plus 5 g/day and to achieve intakes of 25 to 35
g/ day after age 20 years. There are currently no published
studies which indicate optimal dietary fibre intakes for infants
and children under than 2 years of age; until there is more
information, a sensible approach would be to introduce a variety
of fruits, vegetables, and easily digested cereals after
weaning.
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What are the best sources of dietary fibre?
The best sources of fiber are whole-grain products; dried beans,
peas and lentils, vegetables, fruits, seeds and nuts. Refined
foods such as fruit juice, white flour based foods such as white
bread and pasta are lower in fiber content. The refining process
removes the outer coat (bran) from grain, which lowers its fiber
content. Similarly, removing the skin from fruits and vegetables
decreases their fibre content.
Fibre supplements may also be useful is achieving recommended
daily fibre intakes, but as these supplements don’t provide the
vitamins, minerals and other beneficial nutrients that high
fibre foods do, best not to rely exclusively on these.
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Good sources for Dietary Fibre
What sort of meals and snacks can help me to achieve my dietary
fibre goals?
Consider the
following suggestions
to see how small changes like
switching from rice porridge to oats; eating fruit at each meal;
switching from juice to fruit; snacking on whole-grain snacks;
eating an extra serving of vegetables at each main meal; and
opting for brown rice can boost fibre intake.
Any more tips for
ensuring I achieve my dietary fibre intake goals ?
• At Breakfast: Include a bowl of porridge made with millet,
oats or brown rice ; choose whole-grain bread instead of white
bread; try chapatti or paratha (but with less oil) for a change;
try whole-grain ready-to-eat cereals with milk; have a
plate-full of fruit instead of fruit juice or carry an apple to
munch on, on the way to work or school.
• To satisfy mid-morning hunger pangs: Eat fresh fruit; have a
small handful of dried fruits like raisins, prunes, dates,
apricots; grab a few wholegrain crackers;.
• For lunch & dinner: Replace white rice with brown rice when
making rice, fried rice or porridge. Soak the rice before
cooking, to cut down on cooking time. If you eat noodles,
include more vegetables and fruit to increase the fibre content
of the meal. A chapatti with lentils or beans is a fibre-rich
option too. Include a bowl-full of vegetables at each meal. Cook
extra vegetable for every family member or add more vegetables
to fried rice, noodles or porridge. If you have no time to chop
vegetables, take advantage of ready-to-use chopped fresh, frozen
or canned vegetables.
• Eating out? Order an extra serving of vegetables with rice or
noodle-based dishes. Eat chapatti, dosai or idli with lentil
curry or sambhal and vegetables. Ask for a sandwich with
whole-grain bread and extra vegetables in it – have it with a
big portion of salad. End the meal with an array of seasonal
fruits or red bean soup.
• Snack right: Eat fruit between meals. Eating the whole-fruit
instead of peeling or drinking fruit juice will increase fibre
intakes. Grab steamed corn on the cob or corn kernels in a cup
from the street stall vendor, and keep some ready-to-eat
vegetable sticks on hand in the refrigerator.
Is too much fibre harmful?
When increasing the fiber content of your diet, it's best to
take it slow. Add just a few grams at a time to allow the
intestinal tract to adjust; otherwise, abdominal cramps, gas,
bloating, and diarrhea or constipation may result. Other ways to
help minimize these effects: drink at least 2 liters (8 cups) of
fluid daily and use fresh water to cook dried beans and discard
the water in which they were soaked.
Excessive intake of dietary fiber has been linked with reduced
absorption of vitamins, minerals, proteins, and calories.
However, it is unlikely that healthy adults who consume fiber in
amounts within the recommended ranges will have problems with
nutrient absorption.
What’s the take-home message?
Fibre offers many health benefits and prevention of weight gain
and promotion of weight loss is another feather in its cap. So,
do make an extra effort to eat a fibre-rich diet daily if weight
maintenance or loss is a goal. Modest increases in intakes of
whole-grains, beans, vegetables and fruits can help you easily
achieve the recommended range of dietary fiber intake each day.
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References
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