Fiber & Weight Loss

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During your fat loss journey there will be times you are hungry, this is inevitable. Therefore, developing strategies to minimize the length of time and the number of times you feel this way is critical. Not only is this critical for maintaining your sanity, a productive work day, healthy relationships, and your overall well-being, but reducing the amount of time you spend hungry also increases the likelihood you will be successful in achieving your fat loss goals.  

So, how do you do this? How do you keep yourself feeling satisfied between meals while also not eating too many low-calorie voluminous foods that you create other, almost equally uncomfortable, negative physical side effects (bloating, constipation, etc.)? This, is the topic of today’s article...

Not All Fiber Is Created Equal


A commonly held belief is that all fiber is the same, “fiber is fiber”, and it all functions the same way once it enters the body. Not only is this not true, but different types of fiber have entirely opposite effects.

There are two types of fiber: soluble fiber and insoluble fiber. It’s the balancing of these two types which allows us to stay satiated between meals, while also keeping our digestive system functioning smoothly. A brief explanation of each fiber type and where to find it will help guide you on how to strategically use fiber as a tool to aid you in your fat loss success.

Soluble Fiber


Soluble fiber (as the name suggests), is soluble in water. When soluble fiber is combined with water, it forms a thick jellylike substance that slows down the digestion and absorption of food by delaying the rate at which the stomach empties into the small intestine. This, in theory, keeps you feeling satisfied longer after finishing a meal. Because soluble fiber slows down the absorption of nutrients in general, this includes slowing down the rate at which carbohydrates enter the bloodstream. This can lead to better controlled blood sugar levels, help prevent against “crashing”, and eliminate the subsequent feelings of tiredness and elevated hunger.

Soluble fiber can also serve as a prebiotic. Prebiotics, are components of nondigestible fibers that act as food for the healthy bacteria in your digestive system to help nourish and support their growth.

A common myth, is that fiber does not contain calories and can therefore be eaten in unlimited amounts without affecting one’s caloric balance. Although soluble fiber does not directly contribute calories to the human body, the microorganisms in our gut ferment certain types of fiber into short-chain fatty acids (SCFAs) which are then absorbed into our bloodstream and subsequently contribute energy (calories) to our daily total. Depending on the type of soluble fiber, it can contribute between 1 to 3 calories per gram* via these SCFAs.

*A normal gram of carbohydrate provides 4 calories.


Sources: Barley, oats, oat bran, legumes (dried beans, peas, lentils), nuts, psyllium, flaxseed meal, and fruit (apples, oranges, bananas, etc.).*

*Many whole foods contain a blend of both soluble and insoluble fiber.


Now that we’ve looked at a few of the basic functions of soluble fiber, it’s easy to see how overconsuming it could cause problems. Because soluble fiber slows down the digestive system, consuming excessive amounts can cause someone to feel bloated, constipated, and gassy. Overconsumption can also interfere with the body’s ability to absorb various vitamins and minerals, and contributes additional calories to your daily intake.

Insoluble Fiber


Insoluble fiber, is not soluble in water. Because of this, it does not form a jellylike substance but instead works to speed up the digestive system having a natural laxative effect. It works like a broom, helping to “sweep out” your digestive system by pushing everything through. Unlike soluble fiber, insoluble fiber is not fermented by the microorganisms in your colon and therefore does not contribute calories to your daily total.


Sources: Whole grains (brown rice, whole wheat, etc.), wheat bran, corn bran, seeds, nuts, fruit skins, and most vegetables.*

*Many fruits, vegetables, and whole grains contain both soluble and insoluble fiber.

The Balance


As we can see, both types of fiber are beneficial for not only weight loss, but also our overall health. We can see how consuming too much of one without enough of the other could cause problems. Inadequate soluble fiber can lead to elevated hunger, which consuming too much can lead to constipation. Inadequate insoluble fiber can lead to constipation, while excess consumption can lead to diarrhea. Along with the ill effects that come from consuming an imbalanced ratio, ingesting too much total fiber (regardless of the type or ratio) can also lead to negative physical side effects.


So how do we do it? How do we find a proper balance between the two types and ensure we are consuming enough total fiber without consuming too much?


The best place to start to determine how much fiber you should consume, is to look at your current fiber intake. How much fiber are you currently consuming? Are you staying satiated between meals or are you getting hungry again very quickly? Are you experiencing any of the negative symptoms we mentioned earlier?

If you are experiencing issues, look at which fiber type causes that negative effect when consumed in too little or too high of an amount, then adjust accordingly by trying to incorporate more of the lacking fiber type, decreasing the overconsumed type, or increasing/decreasing your total fiber intake.


As a rough guideline, the American Dietetic Association’s position statement on fiber intake is: 14 grams of fiber per 1,000 calories consumed, or 25 grams/day for women and 38 grams/day for men.


Appropriate fiber consumption will vary from person to person, but this gives you a great place to start. If you are currently under consuming fiber and feel you should increase your intake, do so slowly. Adding too much fiber too quickly can cause unwanted side effects. For example, you wouldn’t want to go from consuming 10 grams of fiber per day straight to consuming 30 grams/day. Instead, increase your fiber intake slowly (5 to 7 grams at a time), giving your body time to acclimate and seeing how it responds.

One of the easiest ways to ensure you consume a proper ratio of soluble to insoluble fiber, is to consume a majority of your dietary fiber through whole food sources. The issues which arise from consuming unbalanced ratios are often the result of consuming too many fiber-containing dietary supplements (meal replacement shakes, protein bars, diet ice cream, etc.). This is because most of the dietary supplements that contain fiber use isolated sources of soluble fiber in their products with very little, if any, insoluble fiber. The incorporation of some fiber-containing dietary supplements is okay, however if you are experiencing gastrointestinal discomfort and you eat a lot of fiber containing supplements, you may want to experiment with decreasing your intake to see if this helps.



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