Weight loss with fibers

Meyken Houppermans, PhD. CrossFit Level 3 Trainer
Head Coach and Founder
Lose weight by eating fibers. French fries are a great source of fibers. Fibers have important health benefits such as reduced risk of cardiovascular disease, cancer and type 2 diabetes. Fibers are also predictors for weight loss.

French fries are great source of fibers, more than 100 grams of broccoli. Fibers have important health benefits and can lead to weight loss. But, that does not mean French fries are the best option to increase fiber intake to get healthier and lose weight, considering the high amount of fat and salt.

Dietary fiber explained

Dietary fiber is the term for a group of carbohydrates derived from plants, that are not digested or absorbed by the intestines. Products naturally high in fiber are vegetables and fruit, potatoes, legumes, nuts and whole grain products.White starch products such as white rice and white flour, as well as animal products do not contain fiber. Fiber can also be added to a product, sometimes to replace sugar. Dietary fiber can be classified into two categories:

Fermentable fibers/ pre- biotics

Physical and mental health

This category of fibers, also called pre- biotics, is not digested within the small intestine and therefore not absorbed by the body into the blood stream, because the body does not produce enzymes capable of digestion. As a result, these fermentable fibers enter the colon intact, where certain types of fermentable fibers are available for fermentation by bacteria in the gut. Fermentation refers to the process by which bacteria convert or break down a substance. Fermentable fibers serve as food for the good bacteria in the gut required for physical and mental health.  


Fermentation also releases substances and energy that the body can use. Fermentation releases about 2 kilocalories per gram of fiber on energy, that is used by the intestinal cells. Fermentable fibers are converted into certain fatty acids, such as butyrate and acetate. Butyrate is also an important source of energy for the intestinal cells. 

Healthy cholesterol and good poop

Furthermore, fermentable fibers, especially b-glucans and pectin found in oats, barley and fruits, can lower LDL cholesterol, the unhealthy cholesterol that can lead to atherosclerosis, the clogging of blood vessels. Also nice to know, fermentable fibers help proper bowel movement, and good poop equals good health!

Non-fermentable fiber

Non-fermentable fibers are not broken down by the bacteria in the gut, but leave the body unchanged. They do not provide energy, but they do increase the volume of intestinal contents, which promotes bowel movement.

Pro- biotics and synbiotics

Fermentable fibers are known as pre-biotics, but non- fermentable fibers are not pro-biotics. Synbiotics are products that contain both pro-biotics and pre-biotics.

Health claims of pro-biotics

Pro-biotics are live bacteria or certain yeasts that are claimed to have a positive effect on health when consumed in adequate amounts, such as reducing intestinal and allergic symptoms or increasing immunity. There is little evidence that products containing live microorganisms, such as fermented drinks or pills, provide health benefits for healthy adults. Often, these products contain the lactobacilli or bifidobacteria. To have any effect at all, these bacteria must be live and present in large enough quantities. Often bacteria are already killed in the stomach by stomach acid, or in small intestine by bile. To be at all effective, probiotics must survive the stomach in sufficient quantities. They then reach the small intestine and eventually the large intestine.

The European Food Safety Authority approved only one health claim: Live bacteria in yogurt or fermented milk improve the digestion of lactose in people who have difficulty digesting lactose. To do so, the product must contain at least 100 million live microorganisms per gram of product (to be precise: Lactobacillus delbrueckiisub sp. bulgaricus and Streptococcus thermophilus).[1]

Health benefits of fibers

Most studies into the health effects of fiber concern the health effect of products rich in fiber. Therefore, the role of fiber alone is not always clear and it is important to eat foods rich in fiber, not fiber alone. Three major evidence based health effects of eating fiber- rich products are:

1. Reduced risk of cardiovascular disease to over 20%. Every 7 grams above 25 grams fiber per day is associated with 10% lower risk, mainly due to whole grain cereals.

2. Prevention of type 2 diabetes. Every 10 grams above 25 grams fiber per day is associated with 5% lower risk, mainly due to fiber from whole grain cereals.

3. Reduced risk of colon cancer to 15%. Every 10 grams above 25 grams fiber per day is associated with 10% lower risk of colon cancer and less risk of breast cancer.[2]

Weight loss with fibers

Research shows eating a sufficient amount of fibers promotes weight loss in adults with overweight or obesity. There seems to be a clear association between increased fiber intake and weight loss, independent of other factors such as type of macronutrient intake (carbs, protein or fat). Furthermore, fiber intake also seems strongly associated with adherence to a calorie-restricted diet; how well a person can maintain a diet. 

Fibers promote satiety and satiation

Simply said: fibers make you feel full for longer and less likely to be hungry. These effects vary between different types of fibers. Viscous fibers, such as in beans and sweet potato, were found to reduce appetite and energy intake more frequently than less viscous fibers. Oatmeal, which is high in β-glucan, improves satiety and suppresses energy intake in subsequent meals. 

Fibers reduce calories and inhibit fat absorption

Fibers appear to affect the metabolizable energy of mixed diets, by blunting the digestibility of protein and fat and as a result increasing fecal energy excretion. Although fiber has been shown to inhibit absorption of fats in particular, the association between fiber intake and weight loss did not vary across levels of fat intake. 

Fibers provide smart filling of meals

Research shows energy density influences energy intake and consequently weight status. A diet high in energy content relative to the weight of food in grams is easily consumed in excess, thereby facilitating excessive energy intake and promoting weight gain. Furthermore, these diets often do not contain a sufficient amount of micronutrients (vitamins and minerals). Examples are diets with ultra- processed products such as fast food, snacks and meals with soft drinks.  

Products rich in fibers are often also products low in calories and high in nutritional value, such as vegetables. A large portion of vegetables provides a large amount of healthy food that is satiating and low in calories: a smart filling of your plate. [3] 

Dietary advice

The daily recommended intake is based on the decreased risk of coronary heart disease with dietary fiber consumption. The recommendation is to consume on average 14 grams of dietary fibers per 1000 kcal of total daily intake of food, or at least 25 grams per day for women and 30 grams per day for men. 

Examples of products that contain 3 grams of fibers:

-           40 grams of oatmeal

-           1,5 slices of wholegrain bread

-           1 sweet potato

-           100 grams of broccoli

-           1 large apple

Food labels

In The Netherlands, food producers are not required to list a product's fiber contenton the label. If the food label states a product is a source of fiber, then a food must contain at least 3 grams of fiber per 100 grams, or 1.5 grams per 100 kilocalories. If it says rich in fiber then a product must contain at least 6 grams of fiber per 100 grams, or 3 grams per 100 kilocalories.[4]

Variety and diversity

Variety and diversity in foods and sources of fibers is important, in part because there are many different types of fiber with different functions. Furthermore variety and diversity in foods and sources of fibers are necessary for the proper functioning of the gut bacteria and thus for overall health. It also helps to provide the body a multitude of vitamins and minerals. Additional, variety and diversity in meals is important because every human body has a unique response to food and especially to plant- based food. 

Create your own health!©


[1] Hoe gezond is jouw buik. Artikelen. Wat zijn vezels. Retrieved March 2024.; Miketinas DC, Bray GA, Beyl RA, Ryan DH, Sacks FM,Champagne CM. Fiber Intake Predicts Weight Loss and Dietary Adherence in AdultsConsuming Calorie-Restricted Diets: The POUNDS Lost (Preventing OverweightUsing Novel Dietary Strategies) Study. J Nutr. 2019 Oct 1;149(10):1742-1748. doi: 10.1093/jn/nxz117. PMID:31174214; PMCID: PMC6768815.; Turner ND, Lupton JR. Dietary Fiber. Adv Nutr. 2021 Dec 1;12(6):2553-2555. doi: 10.1093/advances/nmab116. PMID: 34687531; PMCID: PMC8634306.; Encyclopedie. Vezels. Retrieved March 2024.

[2] Encyclopedie. Vezels. Retrieved March 2024. 

[3] Miketinas DC, Bray GA, Beyl RA, Ryan DH, Sacks FM,Champagne CM. Fiber Intake Predicts Weight Loss and Dietary Adherence in AdultsConsuming Calorie-Restricted Diets: The POUNDS Lost (Preventing OverweightUsing Novel Dietary Strategies) Study. J Nutr. 2019 Oct 1;149(10):1742-1748. doi: 10.1093/jn/nxz117. PMID:31174214; PMCID: PMC6768815.

[4] Encyclopedie. Vezels. Retrieved March 2024.