Whenever health, fitness or losing excess body weight are in question, protein intake, low carb diet, ‘good fats’ and ‘bad fats’ are the few topics among many others that are put in the spotlight.
The one thing that was not given much importance earlier was Fibre.
However, recently with the growing interest of people in eating right and staying healthy it has gained much importance.
Which brings us to the question – What is Fibre?
Carbohydrates that cannot get digested by the body are designated as Dietary fibre(DF) or fibre .
These non-digestible carbohydrates include cellulose, hemicellulose, pectin, gums and lignin and are present only in plant foods.
As Fibre cannot be digested they do not add to the nutritive value of foods but are very essential for digestion and often called as ‘Roughage’.
They have low calorific value so a person on a high-fibre diet can consume the same amount food but still consume lesser calories.
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What are the Types of Fibre?
Total dietary fibre(TDF) is of two types. They are:
- Insoluble dietary fibre (IDF)- They form the bulk of stools and aids in easy bowel movements.
- Soluble dietary fibre (SDF)- As they are soluble they bind to the water in the stomach become viscous and delays the stomach emptying time making the person felling satiated.
Foods rich in fibre mostly contain both IDF and SDF but in varying quantities.
The contraction of muscular walls of digestive tract is stimulated by fibre thus they counteract constipation and aid in digestion.
The recommended dietary allowance (RDA) of fibre for adults is 25-30g per day.
The following are various functional benefits of fibre-
- It has been known to maintain blood glucose levels and help prevent type 2 diabetes.
- It is effective in reducing high blood pressure
- Reduces the incidence of heart diseases
- Helps in overcoming obesity
The following study was conducted to determine the effect of fibre intake on obesity, high blood pressure and high blood sugar .
Researchers from University of Massachusetts Medical School recruited 240 volunteers with high blood pressure, high blood sugar, and high cholesterol and who were overweight for a study. They were divided into Group 1 and Group 2.
- Group 1- was given American Heart Association’s (AHA) diet for preventing heart disease, in which emphasis was laid on fruits, vegetables, high-fibre foods, fish, and lean protein and a cut back was made on salt, sugar, fat, and alcohol.
- Group 2-was asked to follow a diet in which the only goal was to eat 30 grams or more of fibre each day.
Both the groups showed reduction their blood pressure, weight and improved response to insulin. In Group 1(5.9 pounds) the loss of weight was more than Group 2 (4.6 pounds).
What does it mean? It tells us that a high fibre diet is not necessarily better than AHA diet. But what it also tells us is that a simple change like increasing fibre in the diet can have profound effects on one’s health.
15 Evidence-Based Fibre Rich Foods That Aid In Weight Loss
The following are a few fibre rich foods one can consume that aid in weight loss:
Pulses make up a major portion of the Indian vegetarian diet.
Pulses contain carbohydrates (slowly digestible starch and resistant starch, dietary fibre), phytochemicals like phytates and phenolic compounds and proteins.
They’re an important source of protein for vegetarians. The slowly digestible starch delays the stomach emptying time.
Most of the nutrients are absorbed on the small intestine, but resistant starch does not get digested in the small intestine and is fermented by bacteria in the large intestine.
It is known to increase satiety and foods rich in resistant starch contain less calories than foods with digestible starch. Less calorie dense food aids in weight loss.
A research study was conducted to determine the effects of dietary pulse consumption on body weight.
The results of the study concluded that the inclusion of pulses in one’s daily diet-induced moderate weight loss even when the diet was not energy restricted.
Along with fibre, Phytates too aid in satiety and delay the return of hunger.
NOTE: Phytates are also called antinutrients as they bind to the minerals and vitamins and make them unavailable to the body. Therefore, lentils should be consumed in proper proportions and its excess should be avoided.
The two things to keep in mind about pulse consumption are that they produce flatulence if consumed in large quantities and that they contain antinutrient phytates. So, they should be consumed in moderation.
What does this mean? The fibre in the pulses along with phytates increase satiety and make it less calorie dense these two factors help in losing weight.
Apples contain good amounts of dietary fibre.
Soluble fibre – pectin in it is responsible for preventing cholesterol build up in the lining of blood vessels, thereby preventing atherosclerosis and incidence of heart diseases.
One apple contains- carbohydrates(34 g, including DF), flavonoid polymers, vitamins (mainly vit. C), and very little amount of protein (around 1g) .
Researchers after tracking a quarter of a million people over 24 years found that flavonoid polymers are linked to weight gain.
They concluded that every extra 138 mg of flavonoid polymers per day was linked to 70-100g less weight gain over intervals of four years.
As we have established earlier that soluble fibre absorbs water, becomes viscous and delays stomach emptying time and leads to a feeling of satiety, we can say the pectin in present in apples aids in weight loss.
A research study indicated that the soluble, fermentable fibre Pectin was more effective than protein in promoting satiety, reducing caloric intake and reducing adiposity.
This data suggests that a high fibre diet may be better for losing weight in obesity than a high protein diet.
What does this mean? Soluble fibre pectin in apples lead to a feeling of fullness and the flavonoid polymers present in apples are associated with loss of weight. Therefore, apple is a good source of fibre rich food whose consumption helps in weight loss.
The role of pear in weight loss is almost the same as apple. Like apple, pear also contains soluble fibre pectin that is responsible for its satiating properties.
Besides that, it is a good source of vitamin C and contains antioxidants and flavanols.
The dietary fibre in them helps maintain health of the gut and regular bowel movements .
A study was conducted in overweight women to investigate the effect of fruit consumption on body weight. Subject was divided into three groups.
And were made to have apple, pear or oat cookies 3 three times a day for a trial period of 12 weeks.
The weight loss (1.2 kg) in the groups who consumed fruits were higher than the group who consumed oat cookies (0.88 kg) .
A single medium-sized pear contains only 100 Calories and 6 g of dietary fibre. The low energy density and good fibre content make them effective in reducing weight.
It is preferred that fruits be consumed mid meals. Consumption of fruits like pear adds fewer calories to the diet and makes a person feel full which restricts the intake of more calories (by making the person eat less and curbing hunger.
What does this mean? A single medium sized pear is low on calories and contains soluble fibre pectin. The fibre induces feeling of satiety and reduces appetite along with curbing hunger. This helps in reducing weight.
4. Psyllium Husk
Psyllium husk comes from the plant Plantago ovata which is native to India.
The seeds of this plant are processed so that the husk can be sold separately as a laxative.
These husks contain large amounts of soluble fire, which swell on absorbing water and form a gel-like consistency. This eases the bowel movements and makes a person feel full.
It has been suggested to have positive effects on body weight reduction and satiety, on cholesterol and triglycerides levels, on fasting glycemia and on blood pressure.
Therefore, there is a potential role of this fibre in the treatment of metabolic syndrome.
Dietary supplementation with 6 g/day of psyllium over 6 weeks improved fat distribution and lipid profile.
This was concluded from a research study conducted on an adolescent population who were at risk of developing metabolic syndrome.
The gel-like consistency leads to the feeling of satiety and restricts the food intake of a person, that leads to weight loss.
It is most effective when consumed before a meal. The husks are to be soaked in a glass of water and then consumed.
However, psyllium supplementation along with a high fibre diet provided the best improvements in metabolic risk factors.
What does this mean? Psyllium husks contains large amounts of dietary fibre of which most of it is soluble fibre that forms a gelatinous mass when it comes in contact with water. This, makes a person feel full thereby reducing the calorie intake and causing weight loss.
5. Fenugreek seeds
Fenugreek seeds come from the plant Trigonella foenum-graecum and are commonly called Methi seeds and widely cultivated in India.
They are widely used in Indian cuisine.
Methi seeds have been used as a folk medicine since ancient times and its numerous health benefits have been listed in the Ayurveda.
They’re used in treating diabetes, fever, boils. They have anti-carminative and aphrodisiac effects.
In addition to its being an antipyretic, anthelminthic, astringent they have been known to possess hypoglycaemic, hypolipidemic and antioxidative effects.
They hypolipidemic effects are mainly due to their antioxidant defense.
Its active compounds include saponins, polyphenols, and soluble fibre.
They contain 45-60 % carbohydrates out of which 48% is dietary fibre, 20-30% proteins, and alkaloids.
They have a particularly bitter taste due to the presence of saponins in them.
Dietary fibre Galactomannan in them forms a viscous gel in the intestine and is responsible for inhibition of glucose and lipid absorption.
The proteins, galactomannan and polyphenols in them are known to regulate dyslipidemia in obese and diabetic rodents.
It was found that fenugreek seed extract was effective in treating obesity induced in mice by a high-fat diet .
Thus, fenugreek extract may be used in the effective treatment of obesity in humans.
What does this mean? Fenugreek extracts have been known to induce weight loss and due to the presence of soluble dietary fibre, Galactomannan, saponins, proteins and polyphenols. The combined action of these promotes satiety and inhibits fat accumulation.
Quinoa is actually the seeds that are harvested from the fruit of the quinoa plant. Because it resembles a cereal grain it is often referred to as a “pseudo-cereal”.
The use of quinoa can be dated back to 1000s of years ago.
It was considered as “mother grain” by the Incas. It has again resumed popularity in recent years due to its nutritional benefits.
Functional foods are foods that have added benefits on health other than providing basic nutrition, quinoa has been recently called a functional food.
Quinoa contains complete proteins unlike other plant sources.
A complete protein is a complex molecule and needs more energy to be broken down by the body causing energy expenditure that helps in weight loss.
It’s a good source of dietary fibre and bioactive compounds such as phenolics that have antioxidant properties.
100g of quinoa contains 7g of DF (dietary fiber) . Of all the dietary fibre in quinoa, 80% of it is IDF (insoluble dietary fibre).
It’s an excellent choice to be included in a gluten-free diet as it doesn’t contain gluten. Studies have suggested that dietary fibre aids in weight loss.
What does this mean? Quinoa is gluten free therefore the carbs in it are classified as good carbs that have various health benefits, its an important source of plant protein and a good source of dietary fibre. These factors combined aid in weight loss.
7. Konjac root
Amorphophallus konjac also known by various names such as elephant root, elephant yam or konjac root is a corm.
They are widely grown in China, Japan, and South East Asia, where they’ve been consumed for years as a food source and as traditional medicine.
Flour extracted from the corm is used to make tofu and noodles in Asian cuisine.
A gel prepared from this flour is used in traditional Chinese medicine for detoxification, tumor-suppression, treatment of asthma, cough and several skin disorders.
It is primarily valued for its naturally occurring Glucomannan content.
The soluble fibre present in the konjac root is Glucomannan.
Purified konjac flour commonly called as konjac glucomannan (KGM) has been introduced to other parts of the world.
It's available as a food additive and dietary supplement.
Glucomannan can absorb water up to 50 times its weight making the most vicious of all soluble fibres.
Therefore, glucomannan, if taken as a supplement, should be consumed in relatively smaller doses than other dietary supplements.
The mechanism of weight loss associated with glucomannan is the same as other water-soluble fibres.
It has a low energy density and has to bulk properties that inhibit appetite by delaying the intestinal absorption and stomach emptying time.
What does this mean? Glucomannan present in konjac root is mainly responsible for its positive effects on weight loss. It’s a soluble fibre that becomes viscous in GIT and inhibits appetite.
Barley is a cereal grown all over the world in temperate climates.
Apart from being popular for its use in beer and malt production, it is an extremely good source of dietary fibre.
Cooked barley contains 3.8 grams dietary fibre .
It also contains proteins and important vitamins and minerals.
Other cereals also contain dietary fibre but barley produces satiating feeling due to the presence of soluble fibre Beta glucans.
In a research study, the different subject groups were given barley, wheat, and rice based food for breakfast.
It was observed that the subjects that were given barley in their breakfast felt more satiated before lunch than the subject groups who consumed wheat or rice.
The molecular size and solubility of beta-glucan in barley consumed also affects their satiating properties.
During the purification and extraction process, these two factors are affected and this explains its varying impacts on satiety.
The form of food also affects the level of satiety. Solid foods are known to be more effective in increasing satiety and decreasing hunger than liquid food.
A research study was conducted in hypercholesteraemic subjects.
A mixture of pearl barley with high beta-glucan content (7g/day) was given to subjects for a trial period of 12 weeks a significant reduction in body mass index, waist circumference and visceral fat was observed as compared to the group of subjects consuming rice alone. Proving beta glucans helps in weight loss.
Another factor affecting level of satiety is glucose and insulin responses to carbohydrate-rich breakfast cereals.
It was observed that the reduced glycaemic and insulin responses to beta glucans are responsible for their satiating properties i.e. glucose and insulin response in inversely proportional to satiety.
What does this mean? Beta glucans is the soluble fibre present in barley and is responsible for inducing the feeling of fullness, however the level of satiety is dependent on factors like the solubility of beta glucans, the form of the food. Therefore, different varieties of barley vary in their effect on weight loss. The way it is cooked also affects beta glucans which in turn leads to difference in the amount of weight loss.
9. Guar gum
Guar or cluster bean is native to India and is used as a vegetable. Guar gum is an extract of guar bean.
It is basically the endosperm of the seed. The guar seeds are processed to produce guar gum.
It is produced as a free-flowing, off-white colored ranging from coarse to fine ground powder.
Guar gum is gel forming Galactomannan. Guar gum contains 75-85 % Galactomannan, 8-14% moisture, 5-6 % protein and 2-3 % fibre .
Galactomannan is a viscous soluble fibre and leads to satiety. Its effects are similar or galactomannan found in fenugreek seeds mentioned above.
It is considered to be a miracle therapy in treating hypocholesteraemia, hyperglycemia and obesity.
A study was conducted to study the effect of guar gum (10 g, twice, daily) in obese subjects.
Short term treatment reduced postprandial blood glucose level by 10%.
Long term treatment showed a reduction in blood cholesterol, reduction in body weight in spite of the subject’s normal dietary habits.
In the trial period of 10 weeks a significant reduction in hunger was observed subsequently leading to weight loss.
What does this mean? 80 % of guar gum contains soluble fibre Galactomannan. It is gel like and delays stomach emptying time and reduces hunger thereby leading to weight loss.
Oats are whole grains and are gluten-free. They are considered extremely healthy because of their nutritive value.
They are a good source of dietary fibre, proteins, and antioxidants. The soluble fibre beta-glucan present in them is the reason of its primary value.
The amount of satiety induced due to beta-glucan is dependent on the solubility and molecular size of beta glucans, the way it is cooked.
And is not related to the amount of fibre consumed as one would like to believe.
In a research study that was conducted it was observed that consumption of 5 g of oat fibre produced more satiety than fibre free foods.
Another study suggested that oats reduced fat distribution and improved liver function.
In this study, obese subjects were randomly assigned to two groups- the control group (given placebo) and the group that was given oats for a trial period of 12 weeks.
The group that consumed oats showed a reduction in their BMI and better liver functioning than the control group.
What does this mean? Oats are rich in soluble fibre- Beta glucan. This soluble fibre curbs appetite and hunger by delaying the stomach emptying time due to its viscous nature.
There is a common misconception among people who are on an energy-restricted diet that consumption of nuts might lead to weight gain as it is rich in fats.
This is not always true, some nuts like almonds, walnuts contain good fats needed by the body.
They contain omega 3 and omega 6 fatty acids which have numerous benefits on one's health.
Epidemiological studies have suggested that consumption of nuts was not associated with weight gain.
However, a clinical trial did suggest that consumption of almonds(50/day) along with an energy-restricted diet, and walk for minimum 30 minutes everyday lead to significant change in BMI and weight loss as compared to the group who consumed other nuts.
Each 100-g serving of almond contains 579 kcal of energy, 49 g of fats, 21 g of protein, 12 g dietary fibre, 21 g carbs, 4 g sugar along with important trace elements and a few vitamins.
The fact that it is not associated with weight gain is due to high satiety and low metabolizable energy (poor bioaccessibility leading to inefficient energy absorption) properties of nuts. (Read Nuts for weight loss)
Only 55-75 % of the energy from nuts is absorbed by the body.
Some data also suggests that daily nut consumption increases resting energy expenditure, and the thermogenic effect of food consumption (expenditure of energy to carry out digestion).
The above-mentioned factors explain the role of nuts in weight loss in spite of being rich in fats.
What does this mean? Almonds contain good fats that have numerous health benefits. The protein and fibre present in them lead to satiety. They are energy dense, but 15-20 % of the energy is not bio- accessible to the body. Also, their consumption increases energy expenditure (increase in resting energy expenditure and thermogenic effect of food consumption). Less availability of energy and more energy expenditure help in weight loss.
Avocado is a unique fruit as its rich in fats as compared to other fruits that are rich in carbohydrates. Its yellowish green flesh is used in the preparation of the popular Guacamole.
100g of avocado contains 1.96 g proteins, 15 g fat, 6.8 g dietary fibre, 8.6 g of carbohydrates and 0.3 g of sugar. Of the 15 g fat 10 is monounsaturated fatty acids (MUFA) and 2g is polyunsaturated fatty acids(PUFA).
They also contain certain vitamins and minerals. It contains 80% water.
MUFA and PUFA both help in prevention of atherosclerosis and coronary diseases and are considered as healthy or good fats.
Avocados are primarily known for their PUFA and MUFA values. However, they are also rich in dietary fibre.
Avocado consumption has been found to associated with improvement in the overall diet quality, nutrient intake, and reduction in the risk of metabolic syndrome (hyperglycemia, hypercholesterolemia, and obesity).
The MUFA rich oil in them increases the bioavailability of carotenoids from salsa and salads, therefore, are often consumed along with them.
A study was conducted in which the 24 hr dietary recall of the participants were recorded. Health evaluation of the avocado vs the non-avocado eaters showed that the former showed higher HDL cholesterol, lower BMI, body weight and waist circumference.
What does this mean?
Avocado is rich in MUFA and PUFA which have numerous health benefits and increase the bioavailability of nutrients present in salads. They are also a good source of dietary fibre and have been found to be effective in reducing the risks of metabolic syndrome which include reduction in weight, LDL cholesterol and reduction in blood sugar.
These are protein-rich legumes and belong to the pea family. They are packed with fibre and proteins. Soybeans come in various varieties and range from brown, black to green colours.
100g of soy contains 36 g of protein, 19 g fat, 30g carbohydrate, and 93 g dietary fibre.
Soybean is primarily known for its high protein value.
They also contain various bioactive compounds like saponins, phytic acid, and isoflavones.
Something just as simple as adding soy fibre to your diet can induce weight loss.
This was confirmed in a study where 39 obese people were randomly assigned to consume control biscuits or biscuits supplemented with soy fibre for a trial period of 12 weeks.
Their health was evaluated after a period of 12 weeks which showed a significant reduction in body weight, BMI, and hypocholesteraemia.
Soy proteins are of great significance in weight loss. Proteins are the most satiating macronutrients.
The feeling of protein-induced satiety is influenced by many components of not just the gastrointestinal system but also the endocrine and neural system.
As soybeans are also rich in protein they lead to more energy (calorie) expenditure because proteins require more energy for their metabolism.
What does this mean? Soybeans are packed with proteins and fibre. Addition of soy fibre to diet has resulted in weight loss. Soy proteins cause protein induced satiety and more energy expenditure that have also been linked to weight loss.
Wheat bran is the hard outer covering of wheat grain.
Usually, in the process of refining cereal grains, this hard-outer covering is removed, which reduces their nutritive value.
Therefore, it is advised to consume whole grains that are with bran.
Wheat bran is rich in fibre, minerals, the B vitamins, vitamin E and phytochemicals such as antioxidants. 100 g of wheat bran contains 36-52 g of total dietary fibre, of which insoluble fibre accounts for 35-48 g and soluble fibre accounts for 1.5-4 g .
As it is rich in insoluble dietary fibre, it is very beneficial in relieving constipation and for healthy bowel movements. Over the year significant data has been accumulated suggesting a positive role of dietary fibre in weight regulation.
What does this mean? Wheat bran has gained significance due to its high fibre content. A high fibre diet has been proved effective in weight reduction. Therefore, consumption of bran may help in weight regulation.
Yellow pea hull contains 82% of fibre and is a good source of protein.
Fibre has often associated with weight loss and one of the reasons for this is that they improve the bacterial gut health.
Consumption of dietary fibres can beneficially modulate gut bacteria populations.
A study conducted on diet-induced obese rats indicated that yellow pea flour reduced adiposity and reduced the percentage of fecal firmicutes. Firmicutes are bacteria that are found in large numbers in obese individuals.
A part of the beneficial impact of gut microbiota is attributed to the by-products produced during fermentation of fibre.
These by-products are primarily Short Chain Fatty Acids (SCFAs). These SCFAs improve fat metabolism.
What does this mean? Consumption of yellow pea mainly in the form of flour improves the gut bacterial health which is co related with reduction of fat. The fermentation of these fibres by the gut bacteria produces SCFAs the improve fat metabolism.
Fiber-rich foods should be inculcated in the diet gradually so that the body can adapt to the change in the diet, otherwise, its consumption might lead to a feeling of discomfort, stomach pain and sometimes even diarrhea.
It is important to always keep in mind that there is nothing such as miracle food that will make you lose significant amounts of fat just by their consumption.
The above-mentioned foods do bring about a reduction in weight but if accompanied by an energy-restricted, healthy diet they can be more effective in bringing about weight loss.