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Ask the Nutritionist: How Much Fiber Do I Really Need?

Q: I know fiber helps keep people “regular.” I’ve also heard it helps flush fat from the body. Is that true?

A: Yes, fiber can help rid the body of some dietary fat. Because the human body is unable to break down fiber, it leaves the body pretty much in the same form it entered. As fiber winds its way through your digestive system, it grabs fats and carries them all the way through to the colon, where a fat-and-fiber package is bundled, water is extracted, and the bundle eliminated from the body. Keep in mind, though, that it’s all a matter of proportion. If you eat half an apple and a whole pizza, the amount of fiber in the apple is not up to the task of scrubbing out all the fat from the pizza.

Q: How much fiber do I need?

A: The amount you need is tied to the number of calories you eat in a day. For healthy adults, the USDA recommends 14 grams of fiber for every 1,000 calories consumed. So a person eating 2,000 calories a day should aim to get 28 grams of fiber daily. In “food” terms, you could hit (and even exceed) that target by eating the following foods over the course of a day: ½ cup oatmeal (3 grams fiber), 1 small banana (3 grams), ½ cup cooked red or black beans (7 grams), 1 small apple (5 grams), ½ cup lentils (8 grams), and ½ cup blueberries (3 grams).

Q: What’s the difference between soluble and insoluble fiber? How do I know if I’m getting enough of each?

A: Soluble and insoluble fiber can be found in different foods, and also in different parts of the same food. Insoluble fiber tends to be found in the peels and husks of plant foods, and soluble fiber is found in the fleshy interior.

For example, grape peels are mostly insoluble fiber, while the inside of a grape is mostly soluble fiber. White rice has mostly soluble fiber, while brown rice has insoluble fiber on the outside and soluble fiber on the inside. Soluble fiber, also called pectin, is what gives apricot nectar its full texture and applesauce its natural thickness. In your body, soluble fibers can help manage glucose levels by slowing the absorption of carbohydrates so that sugar is released gradually into the bloodstream. Carrots, legumes, cabbage, citrus fruits, and green beans are rich sources of soluble fiber. So are the interiors of fresh pears, apples, peaches, and apricots. In addition, some soluble fibers, including those in beans and oats, have been shown to reduce the risk of atherosclerosis and heart disease.

Insoluble fiber, also known as cellulose, is in the exterior of all fruits, vegetables, beans, and whole grains. It’s the peel of an apple, the membrane around the juicy part of an orange, the transparent cover over beans, the strings in a stalk of celery, and the nearly transparent slipcover on each kernel of corn. Because it’s indigestible, it speeds the transit time of food through the body. Insoluble fiber helps to prevent constipation, diverticulitis, and hemorrhoids, and may help decrease the risk of colon cancer.

Unfortunately, food labels don’t distinguish between insoluble and soluble varieties; they simply list total amount of “dietary fiber” in a food. To ensure that you’re getting both types, focus on eating plenty of whole foods, such as an apple rather than apple juice or brown rice instead of white rice.

Q: What is the connection between fiber and weight loss?

A: To lose weight you need to take in fewer calories than you burn. In general, the higher a food’s fiber content, the lower it tends to be in available calories. Here’s why: There are many types of carbohydrates, but they’re not all created equal. Sugar and starch are both carbohydrates. So is fiber. But while your body can easily digest and use calories from sugar and starch, it can’t break down fiber, so you can’t get appreciable numbers of calories from eating the fiber. That’s why you can eat a very large serving of salad, which is almost all fiber, and still eat very few calories.

Q: I sometimes see the term “net carbs” on food labels. Does this have anything to do with fiber?

A: Yes. “Net carbs” refers to the carbohydrate content of a food after the indigestible carbohydrates from fiber have been subtracted. For example, an orange has 60 grams of total carbs from sugar, starch, and fiber; 5 of those carb grams come from fiber. Subtract those 5 grams of fiber carbs from the total carb count, and you have 55 grams of net carbs, or carbs from which you can actually get calories.

Q: Should I use a fiber supplement to make sure I’m getting enough?

A: There are many types of “extracted” fiber products on the market, including tablets and powders that can be mixed with water and taken as a drink. Most health care professionals would advise a healthy adult to eat a pear or a handful of raisins instead of turning to a supplement. Satisfying your daily fiber needs with food is the best way to get a healthful balance of soluble and insoluble fiber. It’s also a great way to improve the overall quality of your diet, since fiber-rich foods tend to be rich in vitamins, minerals, and disease-fighting phytochemicals.

Nutritionist Nancy D. Berkoff, RD, EdD, enjoys cruising for her carbs at local farmers’ markets.


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Comments on this Article

Wow, so informative, easy read and this was digestible for my finite brain!! Thank you Thank you

1/2 cup cooked brown rice, left in the water six hours than cooked, how much fiber?By

on the nutrition facts lable when it says dietary fiber 4g but does not include the soluble or insoluble grams how do I break down the dietary total fiber to get the grams for the other 2. example raisins have dietary fiber listed as 2 grams per 1/4 cup how is this divided into soluble and insoluble? Thank you Bonnie

I'm sorry if this is not the same subject, but I'm as new at writing into magazines as I am at being veggie. I was wondering about protein. Is all protein good? For example, if you see 3 grams on the back of Salt and Vinegar potato chips and 8 grams on mushrooms, is it the same protein? I'm 6 foot, 140 pounds and trying to at least hold onto that weight. Although protein is not the only thing I worry about, it's definitely the one that I check the most. I've recently been eating as much avocado as possible, which was suggested to me. Any advice or suggestions?

Hi Steve, Please send us an email at, and one of our editors will try to answer your questions for you. Thanks! Lisa

What is a good low glicemic natural sugar substitute for baking cakes, pies etc...?

Thanks for all the fiber knowledge!

I love starchy foods but they raise my triglycerides. How do I enjoy eating my fav's (corn, potatoes, rice and pasta) and still lower my tri's?

How much soy is safe to eat I am getting so many conflicting answers. My two young boys and I are vegetarian and we drink a lot of soymilk and eat a lot of the soy products like the nuggets and bacon for example.

Thank you for the information its very helpful.

What can you tell me about coconut water? Is it safe to drink as frequently as the daily recommended serving of water?

I love this article!! Thank you for it.

This article answered all of my questions. Thank you very much and keep up the good work I will probably use this website again.

Carmine, Zylitol is a natural (derived from wood) sugar that will not raise your glycymic index. It has 40% less calories than cane sugar. Adjust your baking to about a 1/4 less Zylitol than cane sugar. It can be found at good health food stores in a 3 lb sack. About $15. It has the side benifit of killing unwanted bacteria in your mouth, may cause GI distress (the runs) if used in excess. Sarah, I would not feed boys very much soy ;-)

This was a very great read, my eyes dried out because I was taking it all in and didn't want to blink ;-)

There is fiber in so many things i ate a triple chocolate chip muffin wit 3 grams of fiber :) yummy yum yum

Michael Hassan, I am a vegan athlete. I eat 3600 calories a day. My fiber is above 50. Today I ate a salad with 5 servings of shelled edamame (5 grams of fiber per serving=25 gms)2 servings of nutritional yeast on a salad (4 grams per serving=8 gms), 4 bean salad (5 grams per serving=5gms), 2 servings of oatmeal (6 grams) 1.5 servings of raspberries (about a cup and a half, 12 grams). Check my math but that should be 56gms. I make a conscious effort incorporate high fiber foods into my diet but it is very doable.

If I'm an athlete and though lean, I eat 3000 calories a day, can I really eat 42 grams of fiber every day and still get enough protein and fat to maintain my weight?

This site is the best by far. I've been searching for answers on fiber since I have just been diagnosed with Diverticulitis. I'm 56 years old and I have to stay on 10-15 grams of fiber a day until I see my doctor in two weeks. How do you stay under that amount?! I am so new to this, and so worried that I may be doing something wrong.

Thank you! Finally some educated answers to all our fiber questions, this site is very helpful.

Most of us don't get enough fiber. When it comes to fiber I want to believe the label is slightly more accurate. Remember when you do something like toasting the bread all bets are off because like all cooked foods you lessen the foods nutritional value. To count your fiber intake the easiest is raw. Like apples. You will more likely be putting in you what the listed value is. Trust your body. If your change your diet on average I've read a 2 month load up period. You body needs time to adjust. Now-a-days there is plenty of websites with nutritional values of most foods cook or uncooked. Goodluck.

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I think it only makes sense to eat as much raw, as well as low sugar foods rich in fiber and protien as we can each day. Too many people try to look at diet programs for short term answers, when all they really have to do is look at what is readily available. Any friut or veggie that can be eaten on the run, from a market or stand, it is the quick fix to good health and hunger!! Everthing in moderation :)

I was doing a report and I found this really helpfull

If I'm eating around 2000 calories a day with around 140 grams of protein-How much fiber should I intake?

Heather, I read on another site that if you eat a 2,000 calorie diet you need 28 grams. Cut that in half (14 grams) if you only consume 1,000 calories in your diet. I believe that was how it was. Hope I helped you any!

Thank you for the best article on fiber I've come across. It makes real sense.


ella PGX powder is good to put on foods. It comes in packets. It is only soluble fiber so make sure you're getting insoluble also

I drink a fiber powder in water every day, about 5-10 grams of fiber. Is that good or bad? im trying to lose a little weight, not a ton. Just extra weight, and I dont know what to do.

; want to know what l can take for fiber that l can use one food,do you have anything

This is the very best article and allows interaction with many people! It's great to share knowledge and tips with others because what works for one person doesnt always work for everyone.

I think I am eating too much fiber. Sometimes it will go about 4 days and then it will hit, sometimes it is immediate. It will hit immediately with spicy foods, too much meat of any kind, some pasta dishes. Do You know what I can do to remedy this?

Good information. My confusion whether rice is rich in soluble or insoluble fiber is cleared from your explanation that brown rice is with insoluble outer coat and soluble inner part whereas, white rice is full of soluble fiber. Many article do not differentiate this and cite rice as example for both soluble and insoluble fiber. thank you.


I am trying to improve my health and I recently learned in my nutrition class what a huge benefit eating the "right" amount of fiber is. I am very excited to see how this works in the next month. I am going to try and make sure I am drinking at least a gallon of water a day and make sure I am eating the suggested amount of fiber from foods and supplements.Thank You so Much!

A very enlightening write up on fibre.

thanks for the info

Very informative!! Thanks!!

i am suffering from jaundice,kindly suggest me a daily diet. Thank You! srikanth

How do nutritionists determine the number of grams of fiber in a food item?

Just starting a high fiber diet, thanks for the info.! Excellent article!

I know I'm not getting enough fiber an needing help in doing so... If I get yogurt what brand an would it help? What are other types of stuff I can get to help regulate myself.... I've tried different things and in dieting need of help

Magnificent goods from you, man. I've understand your stuff previous to and you are just extremely great.

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My son is 11 and is on a gluten free diet. He eats fruits and vegetables everyday and has a bowel movement every 3 days and is overweight. Is he getting too much fiber?

How much fiber do I need for breakfast

Could this personal blogs be viewed by simply people despite the fact that I never order a url?

I'm confused. An article about 12 myths about fiber makes me want to cut back. But when I had a colonoscopy done the Doctor said I needed to take in 40 grams a day to avoid diverticulitis. So which way should I go.

I am a chronic patient of diverticulitis and chronic constipation advised take plenty of fruit and vegetables and fibre diet good results but too much gas in the stomach please advise me. Thanks