Does fiber make you lose weight?
Short answer, yes. However, if you would like to know what the heck dietary fiber is and how it can help you lose weight and improve your health, read below.
First, what is dietary fiber?
Contrary to popular belief, dietary fiber is NOT a nutrient! Yes, that’s right. Fiber is not a nutrient; however, fiber is composed of the parts of vegetables and fruits (mainly carbs) that are mostly indigestible by the human body, thus fiber passes right through the digestive system. Furthermore, dietary fiber could be classified into two main categories; soluble fiber and insoluble fiber.
Soluble fiber is the type of fiber that gut microbes could turn into simple sugars and short chain fatty acids. Soluble fiber turns into a gelatinous material when mixed with water.
Insoluble fiber is the type of fiber that is not absorbed by the body and passes through the digestive system. Insoluble fiber stays intact through the whole process.
Dietary Fiber’s digestion:
Not very long ago, the common thought was that dietary fiber was completely indigestible by the human digestive system, however, modern research has proved otherwise. In fact, it all began with the discovery of the two main types of fiber: soluble and insoluble, however, more recent studies have indicated that we have even more types of microbes that can break down and feed on different kinds of fiber. Most of the fiber will be fermented by gut bacteria to meet their own energy requirements (calories). Majority of the fiber is not digested by the human body, though.
How much fiber is digested?
This question is almost impossible to answer since we would have to know the exact composition of the fiber we are consuming. For example, if you are eating a protein bar that happens to have 10 grams of dietary fiber in it, how could we know how much soluble and insoluble fiber are in those 10 grams? I hope you see my logic now. But, a good practical rule of thumb to go by is 25-50%.
Thus, from my experience, approximately 25-50% of the fiber we consume will be digested by our body.
I have seen some claims floating around the internet that fiber is completely indigestible and thus contributes 0 calories to your energy intake. Bul$%#@t! Read below!
How many calories are in fiber?
To further extrapolate on the point mentioned above about how much fiber is digested, you should count 25-50% of the fiber that you consume towards your calories. Like I mentioned before, fiber is mainly carbs, and we all know that a gram of carbs has 4 calories. Thus, if you are having 10 grams of fiber, you should count that as 40 calories consumed, right? ERRR. Wrong! Remember what I said about fiber types and digestion? Well, applying those facts, you would only count a quarter to a half of that amount. So, if you are having 10 grams of dietary fiber, that should be counted as 10-20 calories! Although, I must say, that it is hard to pinpoint an exact number because it’s hard to predict how much fiber will be digested by the body -most of it is not absorbed-. Individual differences in digestive and metabolic functions play a role as well. To make it simple, just count 25% of the fiber you consume towards your energy content.
How does fiber help you lose weight?
When rust accumulates within your sink’s pipes and clogs them, what do you usually do? Well, I don’t expect you to know but your plumber should! Anyway, your plumber will usually try to solve the problem efficiently by dumping a highly sticky liquid cleaner into the pipes so that the liquid cleans the rust that has accumulated all over the pipes off the inside of the pipes. While this might be a vague analogy, it shows exactly what dietary fiber does.
Insoluble fiber will help you lose more weight by regulating your bowel movement, maintaining an optimal level of pH in your intestines and thus maintaining a well-functioning digestive system. Insoluble fiber will also keep your intestines hydrated which will result in better digestions and bowel movements.
Soluble fiber will help you lose more weight by controlling your appetite since it slows down the digestion process and thus the emptying of the stomach which will in turn keep you fuller for longer. Soluble fiber will also help by maintaining a well-functioning digestion process, maintaining optimal levels of insulin in the blood and lowering your LDL cholesterol levels. Also, fiber in general could boost your metabolism!
Furthermore, dietary fiber has been shown to aid in weight regulation through improving satiation (keeps you fuller for longer) and preventing the absorption of macronutrients (you should still count all calories you consume). Also, dietary fiber has been proven to optimize the secretion of digestive system’s hormones.
Fiber and cholesterol levels
I am sure you have read many times that fiber can lower your cholesterol level and prevent cardiovascular disease. While this might be true, such hyped up claims are usually accompanied with a promotion of a dietary supplement the author is trying to sell, thus, let’s get some facts straight!
Fiber can indeed lower your cholesterol levels. More precisely, soluble fiber. Since soluble fiber slows down the digestion process and break down of food, microbes get to feed on it and break it down into simple carbohydrates they can feed in and in turn create new short chain fatty acids. Those newly created fatty acids could bind to cholesterol, mainly LDL (bad) cholesterol and remove it from your blood stream. So, yes fiber does indeed lower LDL cholesterol. In turn, since TOTAL cholesterol level is calculated by adding up low density lipoprotein -LDL- cholesterol, high density lipoprotein -HDL- cholesterol and triglycerides, it makes sense that if fiber lowers a portion of those three elements (LDL cholesterol) then the total cholesterol level will decrease as well. Applying the same logic, fiber can improve your HDL cholesterol level only by improving the ration of HDL cholesterol to LDL cholesterol. So, marketers, please stop spreading nonsense! But yes, fiber can decrease the risk of heart disease because of this very specific reason.
Fiber and blood glucose levels
Increased dietary fiber intake is inversely linked to spikes in insulin levels. Like I had explained above, soluble fiber slows down the digestion process of food, especially glucose. This effect prevents quick and major spikes in blood glucose levels and helps sustain a balanced level of blood glucose throughout the digestion process. This in turns prevents hypoglycemia as well. The overall result is a decreased risk of cardiovascular disease and prevention of insulin resistance which will also help you lose weight. Take home point; sustaining an even level of insulin in the bloodstream will equal more weight and fat loss.
Dietary fiber can boost your metabolism
Research has shown that when obese subjects where given an increased amount of dietary fiber, they lose weight! However, this CANNOT be solely attributed to an increase in metabolism, but more to the overall health benefits mentioned in this article of dietary fiber. Anyway, logically speaking, since majority of fiber is indigestible by the human body, our bodies still attempt to break it down. While doing so, the body expends energy (calories) to break down the fiber, but since fiber minimally contributes to energy intake, it could be concluded that the body expends more calories breaking down dietary fiber than the calories it gets from it! This effect results in an acute boost in metabolism. Not bad, ha?!
Dietary Fiber Intake Recommendations
Dietary fiber intake recommendations depend majorly on age, gender, weight and pregnancy status. According to the American Heart Association and U.S. department of Health, an individual should aim to get 14 grams of fiber per 1000 calories he consumes. Since nutrients values’ recommendations are based on a 2000 calories diet in the U.S., that recommendation would translate into 28 to 30 grams of fiber per day! If you are an athlete or someone who exercises regularly, try to increase your intake of dietary fiber to 20 grams for every 1000 calories consumed, or 40 grams for an average diet of 2000 calories.
Here is a table from the Journal of Advances in nutrition breaking down the recommended fiber intake recommendations for different age groups from both genders:
Dietary Fiber Deficiencies in Americans
Studies have indicated that on an average day, the average American consumes LESS than half of the recommended amount of dietary fiber! People who follow low carbs and no carbs diets consume even less than that amount (another reason why low carb diets are bul#$@#t). This is most likely related to the fact than an average American diet consists of fast food, meat, and sugar. This is a major contribution to the obesity epidemic that has plagued the U.S. in addition to the increasing death rates from heart and cardiovascular disease.
Foods that are high in fiber
If you missed my article on 11 high fiber delicious snacks that will satisfy your cravings, this would be the time to read it. In addition to getting an optimal amount of dietary fiber, try to vary your fiber sources as much as possible to reap the benefits of both soluble and insoluble fibers and their sub categories of fibers. Here is a list of high fiber foods with their corresponding content of fiber and types of fiber (the numbers are based on average serving sizes):
|Class of Foods||Dietary Fiber Content||Type of Fiber|
|Legumes||10-20 grams||Mucilage, beta-glucans AND Resistant Starch|
|Vegetables||6-10 grams||Lignin, Inulin oligofructose and Cellulose|
|Fruits||5-12 grams||Pectin and gums, Resistant Starch and Mucilage, beta-glucans|
|Nuts||3-6 grams||Cellulose, hemicellulose, and Psyllium|
|Seeds||2-5 grams||Lignin, Cellulose, hemicellulose, Mucilage, beta-glucans, and Pectin and gums|
|Whole Grains||6-10 grams||Cellulose, hemicellulose, Lignin, Polydextrose polyols, Resistant starch, and Wheat dextrin|
How to increase my intake of fiber?
Well, it seems that I have persuaded you to increase your intake of dietary fiber, so kudos to me ha! And good job to you for trying to improve your health and decrease your weight (virtual toast). Anyway, the best and easiest ways to increase your intake of dietary fiber is to:
- Eat more vegetables. Seriously, salad is delicious, so et more of it!
- Eat more fruits. Replace the highly addictive sugary candies with nature’s own candy. It cannot get any better than this.
- Eat more seeds and nuts. Yes, you can have peanut and almond butters, but in moderation due to their high caloric content and low satiety index.
- Eat more whole grains. A simple swap of simple carbs like white pasta, rice and bread for their whole grains/wheat alternatives is the easiest way to boost your intake of dietary fiber.
- Eat more RAW food. Seriously, eat more real food and lower the amount of processed foods your eat.
- Invest in a simple fiber supplement if you cannot get an adequate amount of dietary fiber due to your lifestyle or dietary habits, however, food is always better. A cheap high quality and effective fiber supplement is Psyllium husk. Check it out below.
- Fiber is essential to your overall health and weight loss endeavor. Eat more fiber!
- Aim to eat at least 14 grams of fiber per every 100 calories you consume. This goes for both the average adult and child. In fact, if you are an athlete or perform regular exercise, shoot for 20 grams per 1000 calories.
- Fiber can lower your LDL (bad) cholesterol and improve your overall total cholesterol level and ratio of HDL cholesterol to LDL cholesterol.
- Fiber can control your blood glucose level thanks to its stomach digestion slowing effect.
- There are two main categories of fiber: soluble and insoluble. However, under those categories, there are many other kinds of fiber which all have different functions and health benefits.
- Fiber is found in abundance in fruits, legumes (especially black beans), vegetables nuts, seeds and whole grains.
- Fiber could keep your bowel movement regular and relieve your constipation.
- Fiber can boost your metabolism and thus help you lose more weight.
- Fiber will increase the amount of good bacteria in your gut which will yield a better digestive process and overall health.
- Aim to acquire your dietary fiber from food sources, however, if you cannot, a dietary fiber supplement like Psyllium Husk is fine.
This finally concludes the macronutrients chapter! Awesome! You’ve come a long way. Next chapter will be a very short. In fact, it will only have two articles. The next article will cover an important component of a diet plan: peri workout nutrition.
Haub, J. M. (2010, December 2). Effects of Dietary Fiber and Its Components on Metabolic Health. Retrieved from National Center for Biotechnology Information: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3257631/
JL, S. (2005, March 21). Dietary fiber and body weight. Retrieved from PubMed: https://www.ncbi.nlm.nih.gov/pubmed/15797686
Lupton, N. D. (2011, March). Dietary Fiber. Retrieved from Advances in nutrition – An international review journal: http://advances.nutrition.org/content/2/2/151.full
Surampudi, E. A. (n.d.). Lipid Lowering with Soluble Dietary Fiber. Retrieved from PubMed: https://www.ncbi.nlm.nih.gov/pubmed/27807734
Bowel function and Dietary Fiber from Mount Sinai: http://www.wehealny.org/healthinfo/dietaryfiber/fibercontentchart.html