Benefits Of Fiber For Weight Loss

What is fibre

Dietary fibre is defined to be plant components, not digested by human digestive enzymes, which have an effect on the colonic flora. In theory, dietary fibre has a number of health benefits, but in practice studies are inconclusive. Many commercial fibre supplements contain inulin or psyllium husk, which are soluble fibres. Dietary fibre is a broad term used to describe plant components that are not broken down by human digestive enzymes and include non-starch polysaccharides (NSP) and lignin. Resistant starch, oligosaccharides, and pectin are the insoluble fibres that the digestive system cannot break down. Using either a physiological definition or chemical definition of dietary fibre associated with dietary intake guidelines from government health agencies, most nutritionists recognize that there are large differences in fibre types within different foods, thus making it important for individuals choosing a diet to understand this terminology more fully.

Dietary fibre contributed to the evolution of early man and has a beneficial effect on health. Fibre may provide a direct mechanical effect on the gut, reducing energy consumption and/or absorption. Furthermore, fibre intake at a meal can lower blood glucose levels, that is mediated via effects on gut hormones such as enteroglucagon and gastric inhibitory polypeptide; these hormones may independently reduce satiety and/or substrate utilisation.1

Benefits of fibre for weight loss

As fibre is not digestible the extra bulk is added to your stool, which helps you to stay regular and light. It helps keep the heart healthy, reduces low-density lipoprotein (LDL) cholesterol and lowers blood pressure. You may not realise it yet, but fibre plays a huge role in terms of your weight issues. Fibre helps make you feel fuller for a longer time due to its amazing effect of slowing down digestion, thus managing insulin and blood sugar response to food. High fibre foods are low in calories, sugar and fat thus are generally healthy. Hence, fibre helps make you less inclined to overeat.

Isn’t that great in itself?

That’s right—you just found out why high-fibre foods are so good for you!

Other health benefits of fibre

One of the many reasons why a high-fibre diet is an important part of a healthy lifestyle is because it normalises bowel movements. Dietary fibre increases the weight and size of your stool thus softening it. Fibre can also help maintain bowel health. Soluble fibre found in beans, oats, flaxseed, oat bran may help lower total blood cholesterol levels by loweringLDL, or "bad," cholesterol levels. Fibre is good for diabetics as it helps control blood sugar. A high-fibre diet can also help you reach and maintain a healthy weight because it tends to be more filling than low-fibre foods. Fibre helps lower cholesterol levels in certain patients. In fact, soluble fibre found in beans, oats, flaxseed and oat bran can help lower total blood cholesterol levels by lowering LDL levels.. Haemorrhoids and diverticular disease - which are small pouches in the colon - can be eliminated with a fibre rich diet.

Fibre also aids in achieving healthy weight and helping you live longer.

Source: Mayo Clinic

Theoretical roles of Fiber in Energy Regulation:2

  1. Energy Dilution: including a high volume of dietary fibre in the diet resulted in a reduced energy intake and increased satiety
  2. Chewing: foods rich in fibre take longer to be masticated thus leading to a feeling of satiety and less ingestion of food
  3. Gastric Distention: as chewing fibre is a prolonged task, fibre may promote gastric distention due to the additional production of gastric acids and saliva
  4. Gastric Emptying and Rate of Nutrient Absorption: Soluble fibres have a polysaccharide structure  or a combination of both. It absorbs water slowly, forming bulky viscous gel in the stomach. This slows down gastric emptying and delays digestion2
  5. Caloric Excretion: Diets high in fibre reduces energy required for digestion and helps contribute in managing long term weight management3

We have more bacteria that live in the human body than our body’s cells. Bacteria live everywhere and our gut is the one that primarily holds the majority of it. Gut bacteria is known as gut flora. Gut flora needs to survive and fibre is essential for their survival. Carbs, proteins and fats are absorbed into the bloodstream thus leaving little for the flora. Here is where fibre proves to be the food for the intestinal bacteria which is easily broken by them as they have the enzymes to digest many of these fibres. Thus, dietary fibres are essential for health as they provide for the good bacteria which functions as prebiotics in the intestines. As the bacteria ferments the fibre, people are prone to flatulence. This is the reason why diets high in fibre make people gassy and experience stomach aches. These side effects are known to subside as the body adjusts with time.

Natural food sources of fibre

The natural sources of fibre include beans, whole grains, popcorn, brown rice, nuts - almond, pecans and walnuts -, berries, bran cereal, baked potato with skin, green leafy vegetables and oatmeal.

Dietary fibre is classified as: Soluble Fibre and Insoluble Fiber. They are important for preventing diseases, helping in digestion and keeping the gut healthy.

  1. Soluble Fibres: as the name suggests are the ones that attract water and turn into gel during digestion. This is what makes the digestion process slower. Oat bran, beans, nuts, seeds, barley, lentils, peas, certain fruits and vegetables are all sources of soluble fibres. A popular fibre supplement- psyllium - is a rich source of soluble fibre. Soluble fibre is also known to help lower the risk of heart diseases
  2. Insoluble Fibres: are the ones that add bulk to the stools and help food to pass quickly through the stomach and intestines. These include wheat bran, grains and vegetables

Fruits, vegetables and nuts have been considered as dietary fibre. Fruits and vegetables account for around 16% and 30-40%  of fibre content respectively in Western countries.4

The constituents from dietary fibre in fruits and vegetables are cellulose, hemicellulose and polysaccharides.4

Side effects and other concerns

Usually, people fail to have their recommended fibre intake, and too much fibre can be a concern when you increase your fibre intake rapidly. It may lead to:

  • Bloating, anorexia and abdominal pain
  • Flatulence, diarrhoea, loose stools or constipation
  • Temporary weight gain
  • Intestinal blockage in people suffering from Crohn’s disease
  • Reduced blood sugar, this is important to know in case of diabetics 

Now let’s look at what effect fibre has on constipation.

One of the main benefits of having fibre is that it helps relieve constipation because it is known to absorb water, increase the bulk of stool and speed up elimination of it through the intestine.

On the other hand, certain studies show that removing fibre can help improve symptoms of constipation. This depends on the type of fibre consumed. Fibre that increases the water content of your stool has a laxative effect (soluble fibre), whereas fibre that adds bulk to stool without increasing any water content (insoluble fibre) leads to a constipating effect. Examples of soluble fibre include psyllium, prunes and sorbitol, all of which draw water into the colon thus having a laxative effect. You can rid your symptoms of constipation by choosing the right type of fibre, but taking the wrong supplement can quite do the opposite. Hence, it is always necessary to consult a healthcare professional before taking any fibre supplement for constipation.


Fibre is categorised under soluble and insoluble fibre which can be further also called as gel-like quality, or fermentable as it acts as food for the gut bacteria that breaks it down and ferments it. Fibres that don’t break down are the ones that pass through the colon and add bulk to the stools. These are combined with health benefits of slowing down the digestion process, delaying raised blood sugar level after meals, providing good bacteria for the gut and has laxative properties.

A great solution for weight management in diabetic individuals is to go high in carbohydrate and soluble fibre content and moderate in protein content.

If there is an insufficient intake of dietary fibre, the most common problem is constipation. Other issues associated with less intake of dietary fibre is colonic diverticulosis, haemorrhoids, obesity, diabetes and even heart diseases.5

Proper advocacy of diets promoting high fibre foods combined with fruits, vegetables, and legumes can help people to eat right and stay healthy. Studies have found fibre helps in gastric emptying, gut hormones, satiation and glycemic index.5

Consulting a nutritionist who can better guide on various types of dietary fibre for its effectiveness, difference in the response that fibre has on obese and lean individuals and understanding the mechanisms on how dietary fibre aids in energy regulation is always advised.

Here are some tips on how you can increase your fibre intake:

  • Ditch the juice pack and instead eat your whole fruit
  • Replacing pasta, white bread and rice with brown rice and grains like barley and millet
  • Handful of high fibre foods such as almond, flaxseed, chia seed or high fibre cereal instead of chips and chocolates
  • Sautéed vegetables and soups, beans or legumes twice a week
  • Fibre supplements that include- psyllium or methylcellulose. Not to be completely replaced with high fibre foods


  1. Anderson JW, Akanji AO. Dietary fiber—an overview. Diabetes care. 1991 Dec 1;14(12):1126-31.
  2. Howarth NC, Saltzman E, Roberts SB. Dietary fiber and weight regulation. Nutrition reviews. 2001 May 1;59(5):129-39.
  3. Bonfield CT. Dietary fiber and body weight management. Dietary fiber in health and disease. 1995:459-65.
  4. Esteban RM, Mollá E, Benítez V. Sources of fiber. InDietary Fiber for the Prevention of Cardiovascular Disease 2017 Jan 1 (pp. 121-146). Academic Press.5.  Slavin JL. Dietary fiber and body weight. Nutrition. 2005 Mar 1;21(3):411-8.
This content is purely informational and isn’t medical guidance. It shouldn’t replace professional medical counsel. Always consult your physician regarding treatment risks and benefits. See our editorial standards for more details.

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Tasneem Kaderi


Tasneem is a dental practitioner since 5 years in India. She is also a Medicolegal consultant plus Hospital and Healthcare Administrator since 2 years. She has a diploma in Clinical Research and Pharmacovigilance and is working as a Data Analyst for Medical Devices at 3Analytics, California. An avid reader and optimist at heart, loves to scribble here and there.

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