Fiber absorbs calories?

Bigger Stronger Leaner Competitive Bodybuilding
1

There is an interesting article on this web page (http://www.ars.usda.gov/is/qtr/q397/hn397.htm) that states that “fiber intake can reduce the number of calories your body absorbs from the foods you eat.” Could anyone shed some more light on this topic? I have not been successful in finding even one more official study that could substantiate this claim. I would think that it is common knowledge that fiber reduces absorption of some calories, but I would like to know by how much. This study makes the claim the number to be anywhere between 90 and 130. On another website, an individual made the claim fiber blocks 7 calories per gram, yet another website said it’s anywhere between 30-180. Needless to say, I am very confused. Any answer would be much appreciated.

Thanks,

Jonez.

2

Interesting but puzzling stuff. At first I thought they meant that high fiber diets might reduce overall food consumption (satiety or what not) but they’re referring specifically to ‘absorption’ of food.

-Zulu

3

…And if you’re not absorbing the calories from the food are you then also missing out on valuable nutrition?

-Zulu

4

I know that dietary fiber will bind that free fatty acids that are liberated during the digestive process from triglycerides and prevent them from being absorbed.

I’ll look into the studied amount that is believed to be unabsorbed and get back you.

But even if the fiber prevents say 5 g of fatty acids from being absorbed, that would equate to only 45 kcals lost.

5

Thanks a lot Cassanova, I look forward to hearing from you.

You have a nice day,

Jonez.

6

Since fiber slows down the transit time food takes to move through the gi tract, I would think a high fiber diet would better allow nutrients to be absorbed. This seems especially true since food would be in contact with intestinal tissue for a longer period of time. Make sense to anyone else?

7

Jonezy,

You might want to take a look through the Previous Issues section and find the article with regard to Dr. Lonnie Lowery’s Guest Forum. He touched on this then.

If I recall correctly, he mentioned that he wasn’t aware of any exact numbers.

He also talks about, or at least touches on, this very subject in one or more of his articles here on T-Mag. I strongly urge you to review those articles, if for nothing else, references in the literature that may assist you in finding your answers.

Here are a few references that you might find handy in your research:

Baer DJ, et al. Dietary fiber decreases the metabolizabel energy content and nutrient digestability of mixed diets fed to humans. J Nutr 1997; 127: 579.

Wrick KL, et al. J Nutr 1983; 113: 1464.

Miles CW, et al. J Nutr 1988; 118: 1075.

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Snatchy,

Remember, the type of fiber is important. Insoluble fiber actually hastens transit time through the GI tract.

9

Thanks Timbo for your response. From what I gather, dietary fiber does indeed absorb calories - how many calories though is uncertain (although numbers are presented in those studies you give). In my opinion though, the amount of useable calories in fiber (short chain fatty acids) would not have a significant affect on body composition due to calories being absorbed elsewhere in the body. I may be wrong though, but it seems to make some sense. I guess I’ll continue supplementing with guar gum since it can only benefit me.

Thanks again,

Jonez.

10

Just to add to this, wasn’t that chitosin stuff that “blocked fat” some type of fiber?

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Jonsey,

It’s not that fiber itself absorbs fat. Rather, fiber binds with fat before it’s digested and thus reduces the bioavailability of the fat for digestion and absorption. In essence, on a meal-by-meal basis, this is probably not very significant.

Also, Jonsey, I’m not sure what you meant by fiber being a “short-chain fatty acid.” Fiber is a form of carbohydrate, although not digestable by the human body.

Mr. Reality…You are correct, sir. Chitosin is a fiber from shellfish that was supposed to exert “special” qualities of binding selectively to fat thus disabling digestion. There are probably several factors that contributed to the decline in popularity of this fiber being sold commercially for weight loss. Namely because it didn’t pan out to be a magic pill.

12

Timbo,

Check out this post I made about soluble fiber yielding calories:

I take close to 27 grams of guar gum (soluble fiber) daily and was thinking that that those extra calories (from the fiber) would lead to weight gain if I went over my daily calorie limit. If it’s true that fiber will block the absorption of some calories, maybe I don’t have to be so concerned about this.

Also, the studies that I’ve read reveal that fiber will reduce fat AND protein absorption.

Thanks,

Jonez

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Possibly [Zulu]. I have done some Alternative Medicine [The Definitive Guide] reading. It recommends never taking fiber with supplements. Meaning the fiber will interfere or reduce the absorption of the supplement. It does not talk about the effect on calories. I thought this would be a good tidbit to add since many of us use supplements.

14

honestly if you do eat 6-8 meals a day…you can easily get say 3-5 grams of fiber with each real food meal or MRP and that shouldnt relaly mess up anything to badly absorbtion wise, I mean when you have like 15 grams sol-fiber and 10 insol fiber in one meal…damn right you are gonna lose calories hehe…especially cause your gonna burn a few on the pot haha. Personally i add 5 grams psyllium to my prots shakes ( only outside of my workout pre and post) You dont want things sitting in your intestinal track too long, also right at night some cottage cheese+prot…enzymes and fiber you wake up ready to hit the bathroom hehe. I noticed alot less gastric distress (aka farting) when i do the 5 grams psyllilum but if i go realy high cause of say beans or veggies with fiber the partial break down your body can do to fiber def gets things moving, as in gas. its almost like you body gets used to a certain amount, but there is some kinda of limit.

15

Okay y’all, (And this includes you too Sweet-T)

I’m going to make some clarifications about dietary fiber to help you understand what happens during digestion.

Dietary fiber may be classified as water-soluble or water insoluble; fibers that dissolve in hot water are soluble, and those that do not are insoluble. In general, water-soluble fibers include some hemicelluloses, pectin, gums, and mucilages. Cellulose, lignin, and some hemicelluloses are classified as insoluble. Generally, veggies and wheat along with most grain products contain more insoluble fibers than soluble.
Solubility in water also may be used as a basis to broadly divide the characteristics of fibers. For example, soluble fibers delay gastric emptying, slow movement of digesta (increase transit time) and decrease nutrient absorption. In contrast, insoluble fibers decrease transit time (speed up), and increase fecal bulk.

Water holding capacity however, is not just dependant on the fiber’s solubility. The pH of the GI tract, size of the fiber particle, and/or degree of processing also influence the water holding capacity and in turn it?s physiological effects. Coarsely ground bran for example, has a higher hydration capacity than that which is finely ground. Consequently, coarser bran with large particles holds water, increases fecal volume, and speeds up the rate of passage.

Delayed Gastric Emptying:

When fibers form gels, in the stomach, the release of chyme from the tummy into the duodenum is delayed. Thus, nutrients remain in the stomach longer with these fibers. This creates higher satiety postprandial, as well as slows down the digestive process, because carbs and fats that remain in the stomach undergo no digestion and must move to the small intestine for further digestion to occur.

Reduced Mixing of GI Contents with Digestive Enzymes:

The presence of viscous gels in the GI provides a physical barrier that can impair interaction of food nutrients with digestive enzymes.

Reduced Enzyme Function:

Gel-fibers can interfere with the enzymatic hydrolysis of nutrients in the GI. Some fibers can interfere with peptidases (amino acid enzymes) that are necessary for complete protein metabolism. Pancreatic lipase can also be inhibited and cause decreased fat digestion. It’s not clear whether fiber directly decreases enzymes or acts by reducing the rate of enzyme penetration.

Reduced Diffusion Rates:

The gels can cause decreased absorption of nutrients into the enterocytes (intestinal cells). Amino acids, glucose and fats are all affected by this process. Decreased diffusion may in turn result in nutrients “missing” their normal site of max absorption in the intestine.

So, as you can see from this, fiber can decrease the amount of nutrients that you absorb, which would then in turn, decrease your caloric intake.

See? Your mother was right. Eat your veggies, fruit, bran, and whole grains. Not only will they help to keep you fuller longer, they may allow you to eat more, because you absorb less.

And Tim, do you understand how fibers can become short chain fatty acids from my previous post? If not, I’ll put it up again.

Cassinator :=)

16

niiiice Cass!
thanks for that, that goes in the t-forums copy paste file :slight_smile:

17

So, in actuality, how many calories should we ‘subtract’ from high fiber foods? (I’m just curious, I won’t be doing calculations with it)

BTW, maybe I’m getting it wrong but are fibers then seen as negative calories? Ie: instead of pysyllium having 4 cals/gram wouldn’t it be like -1cals/gram? Isn’t all fiber at the worst non-caloric? (It seems food labels don’t take this into account…)

-Zulu

18

Cass,

You’re money, baby! We’re talking Benjamins here, kids. Nice post, chock full of information. And, yes, I’m feeling you on the SCFA issue.

And, just to reitterate what the Cassinator (and I) have been saying, don’t worry about an exact number of kcals to add/subtract due to this fiber/absorption phenomena. You could spend your time much more efficiently and worthwhile.

19

Timbo and Cass,

Can you guys explain to me in layman’s terms exactly what is happening when I supplement with fiber as I am still unsure after having read your post. Basically my last meal consists of protein(whey), fat(udo’s oil) and a calcium sup. I also supplement with 5g of psylium husk so if I am understanding correctly, it will speed up the digestion process(not good) as well as prevent absorbtion(also not good). So the question is should I stop supplementing with fiber or is it a case where the good out ways the bad?

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I just wanted to say that Cass is a freaking machine. You’re making me feel dumb.