Fibre for weight loss – which is the best?

Dietary fibre is a collective name for a group of plant-based compounds that are not digested in the human digestive tract. Contrary to appearances, fibre is not a single component, but a collection of different substances with different physicochemical properties, such as water solubility, viscosity and susceptibility to fermentation. Although it does not provide energy, its role in the body cannot be overestimated – from mechanically supporting intestinal peristalsis to influencing the intestinal microflora, the feeling of satiety and the regulation of metabolism.

1. Fibre and weight loss
2. Soluble fibre – how does it work and where to find it?
3. Exotic and lesser-known sources of fibre – from bamboo to acacia
4. Resistant fibre – fermentation, SCFA and the gut microbiome
5. Functional and synthetic fibre – a food ingredient or a technological additive?
6. Is it worth mixing different sources of fibre? What do scientific publications say?
7. Summary – how to choose fibre for your needs?

Fibre and weight loss

In the context of weight loss, fibre has gained particular interest due to its ability to increase the volume of food content, delay gastric emptying and fermentation, leading to the formation of compounds that affect hunger and satiety centres. It is the diversity of fibre structures that makes its effects vary significantly depending on the source and form of consumption. In this article, we will look at which fibre fractions best support weight loss and where they can be found.

Soluble fibre – how does it work and where to find it?

Soluble fibre plays an important role in the diet of people who care about their figure, because when combined with water, it forms a sticky gel that slows down gastric emptying and can contribute to a prolonged feeling of satiety. This fraction of fibre also has the ability to be fermented by gut bacteria, resulting in the formation of short-chain fatty acids, such as butyrate, which affect glucose metabolism and hormonal signalling in the digestive tract.

Pectins

The best-known sources of soluble fibre include pectins found in fruit, beta-glucans present in oats and barley, and inulin and fructooligosaccharides naturally found in chicory, onions and garlic. Scientists are also particularly interested in psyllium and plantain, which contain mucilage capable of strongly binding water and forming a mass that increases the volume of intestinal contents.

Main advantages

The polysaccharides they contain not only gently support peristalsis, but also help control appetite and provide a breeding ground for intestinal bacteria. Studies have shown that psyllium supplementation increases satiety, reduces spontaneous calorie intake and supports regular bowel movements, making it a particularly interesting ingredient in weight-loss diets.

"Soluble fibre, when consumed in adequate amounts, lowers LDL cholesterol levels and increases insulin sensitivity. These properties reduce the risk of cardiovascular disease." Agata Bugorska - Personal trainer IFAA trainer

Insoluble fibre - how does it support mechanical digestion?

Insoluble fibre differs significantly from soluble fibre in both physicochemical and functional terms. It does not form gels and does not dissolve in water, but passes through the digestive tract in an almost unchanged form, absorbing water and increasing the volume of faecal matter. This accelerates intestinal transit and prevents food retention, which can bring relief to people prone to constipation.

Action

Although it does not directly affect satiety through fermentation, its presence in the diet physically fills the intestines, which may indirectly reduce the amount of food consumed. The main sources of insoluble fibre include bran, whole grain products, nuts, seeds and the skins of many vegetables and fruits. It consists of cellulose, hemicellulose and lignin, which are not broken down by digestive enzymes or intestinal bacteria.

Although this type of fibre does not significantly affect the microbiota, its presence in the diet can support bowel movements and reduce the feeling of heaviness after meals, which makes it easier to maintain a weight-loss diet.

Exotic and lesser-known sources of fibre – from bamboo to acacia

A weight-loss diet should include not only classic sources of fibre, but also less obvious additives that are increasingly found in functional foods.

Bamboo fibre is an example of a virtually insoluble ingredient obtained from young bamboo shoots. Thanks to its very fine structure and high lignin content, it primarily acts as a filler, mechanically supporting intestinal function. Publications have shown that it can increase the volume of faecal mass without excessive fermentation, making it beneficial for people with sensitive digestive tracts.

Acacia fibre, also known as gum arabic, belongs to the soluble fraction and is characterised by high intestinal tolerance, mild action and prebiotic properties. Studies indicate that it can support the growth of beneficial intestinal bacteria, such as Bifidobacterium, which indirectly affects metabolic processes.

Apple fibre. Apple fibre is also worth mentioning, as it contains significant amounts of pectin and phenolic substances, combining gelling properties with antioxidant potential.

Cocoa and coconut fibre. Cocoa and coconut fibre are also growing in popularity. In addition to their physiological properties, they provide intense flavours and are used in products without added sugar.

Artichoke and chicory fibre is a rich source of inulin, which has a strong prebiotic effect and can be particularly useful in the diet of people seeking to reduce their appetite and improve their bowel movements.

Potato fibre. Potato fibre, known as resistant potato starch, should also not be overlooked. It passes undigested into the large intestine and undergoes fermentation, producing effects comparable to those of resistant fibre.

Resistant fibre – fermentation, SCFA and the gut microbiome

Resistant fibre is a special form of starch which, despite the presence of digestive enzymes in the small intestine, remains unabsorbed and is only fermented in the large intestine. There are several types of resistant starch, referred to by the abbreviations RS1 to RS5, which differ in their chemical structure and source of origin. It is found naturally in foods such as unripe bananas, cooked and cooled potatoes, rice, lentils, beans and whole grains.

"Gut health has a direct impact on the functioning of the immune system, and inulin acts on the gut microbiome, which plays a key role in defending the body against infections. Regular consumption of inulin helps to increase the population of beneficial bacteria in the gut, which support the production of short-chain fatty acids (SCFA)." Łukasz Domeracki - MSc in Food Technology

Particularly beneficial for the gut

Studies have shown that the fermentation of resistant fibre leads to the formation of short-chain fatty acids, including butyrate, which plays an important role in the nutrition of intestinal epithelial cells and also influences metabolic and immune signalling. Of particular interest is the effect of resistant fibre on the brain-gut axis, including the secretion of hormones such as GLP-1, which can modulate appetite and contribute to reduced calorie intake.

For this reason, resistant fibre is considered a valuable component of a weight-loss diet, especially when combined with other prebiotics. It is worth noting that its effect is slower but more stable over time, and regular consumption can lead to a permanent change in the composition of the gut microbiota, as demonstrated in numerous clinical interventions.

Functional and synthetic fibre – a food ingredient or a technological additive?

With the development of the food industry, functional fibres, i.e. ingredients deliberately added to products to increase their health value or improve their texture, are increasingly finding their way into our daily diet. This group includes, among others, polydextrose, microcrystalline cellulose, isomalto-oligosaccharides (IMO), fructooligosaccharides (FOS) and galactooligosaccharides (GOS). Although they are synthesised outside the plant organism, many of them have fermentative properties and can support the development of beneficial gut microbiota.

For example, polydextrose is a synthetic, low-calorie fibre that is well tolerated even in larger amounts and can increase the feeling of satiety. Microcrystalline cellulose, on the other hand, mainly acts as a filler and consistency regulator, without significant fermentation. FOS and GOS, on the other hand, are powerful prebiotics and are often found in products for children and people with sensitive digestive systems.

Although functional fibre does not fully replace the diversity of natural fibre, its presence in a modern diet can be beneficial, especially when natural fibre intake from vegetables and fruit is insufficient. However, not all synthetic forms work identically, so their effect on body weight and satiety depends on their chemical structure and dosage.

Is it worth mixing different sources of fibre? What do scientific publications say?

Studies on the effectiveness of fibre in weight loss increasingly emphasise the importance of its diversity. Different types of fibre, soluble and insoluble, resistant and fermentable, have different effects on the body, and combining them can be more beneficial than using a single source.

Why diversity?

Soluble fibre delays gastric emptying, resistant fibre supports the gut microbiota and butyrate production, while insoluble fibre mechanically regulates intestinal transit and promotes a natural bowel movement rhythm. Fibre diversity can also facilitate gastrointestinal adaptation, reducing the risk of bloating or discomfort that sometimes accompanies a sudden increase in the consumption of one type of fibre.

Publications describe how a diet rich in mixed sources of fibre can lead to weight loss, lower fasting glucose levels, improved lipid profile and a greater feeling of satiety after meals. It is the synergistic effect of different types of fibre that makes their presence in the diet important not only for the intestines but also for the entire metabolism, and their skilful selection can support effective and sustainable weight loss.

Below is a comparative table of dietary fibre types, taking into account their use in the context of weight loss. In the columns, I have highlighted the most important features of each type, and in the last column, their usefulness in weight reduction.

Conclusions

The greatest effect on satiety and appetite reduction is shown by: psyllium, beta-glucans, pectins

Resistant fibre and inulin support the gut microbiota and SCFA production, which affects metabolism and hunger regulation

Insoluble fibre (e.g. bran, bamboo) acts mainly mechanically, aiding bowel movements, but is less important for appetite

Supplementation with a mixture of different fractions may produce the best reduction effects

Summary – how to choose fibre for your needs?

Dietary fibre is not a uniform component, and its effect on the body depends on its chemical structure, origin and fermentability. In the context of weight loss, soluble and resistant fibres work best, as they increase the feeling of satiety and affect the gut microbiota, but insoluble fibre also plays an important role as a passage regulator and physical filler.

Ingredients such as psyllium, chicory inulin, acacia fibre, resistant potato starch and apple fibre can be a valuable addition to a weight loss diet, especially when combined with vegetables, whole grains and legumes. Fibre supplementation can be beneficial, especially when natural fibre intake is low, but it should be tailored to the individual so as not to disrupt bowel function.

Supporting weight loss with fibre therefore requires not only its presence in the diet, but also a thoughtful selection of sources that complement each other. The best fibre is one that is varied, well tolerated and actually supports eating habits that lead to weight loss.

Sources:

• Dietary fiber and weight https://pubmed.ncbi.nlm.nih.gov/15797686/
• Effect of psyllium on gastric emptying, hunger feeling and food intake in normal volunteers https://pubmed.ncbi.nlm.nih.gov/9578335/
• Metabolic benefits of dietary prebiotics in human subjects https://pubmed.ncbi.nlm.nih.gov/24230488/