Fiber Math on the Fly

There’s no shortage of interest in dietary fiber. We know fiber is good for us, but we also know that most Americans are not getting enough fiber.

While the Institute of Medicine Dietary Reference Intakes and the Dietary Guidelines for Americans, 2010 recommend between 25-38 grams of fiber per day (for adult females and males, respectively), it is estimated that Americans, on average, eat only 15 grams of fiber per day.

As a nation, we are eating only about half of our daily fiber needs.

While there are some fancy electronic fiber calculators and screeners out there (see recent posts on fiber counter tools here, here, and here), sometimes you have to rely on good old-fashioned math.

How to determine daily fiber intake

Calorie counter
Woman using calorie counter application on her smartphone

Here is a quick and dirty estimation method for determining average daily fiber intake. To use this, you will need a one-day (24-hour) food record.

To estimate average daily fiber intake from a food record:

  • Multiply the number of fruit and vegetable servings by 1.5 grams (a fruit/vegetable serving is 1 cup raw or 1/2 cup cooked)
  • Multiply the number of whole-grain servings by 2.5 grams (a whole grain serving is roughly 1 oz or 1/2 cup cooked grain)
  • Multiply the number of refined grain servings by 1.0 grams (a refined grain serving size is the same as whole grain)
  • Add specific fiber amount for nuts, legumes, seeds, and high-fiber cereals
  • Total to estimate fiber intake per day

This fiber estimation method is a tool developed and published by researchers at the University of Wisconsin, Madison. It is especially helpful for healthcare practitioners looking to estimate fiber intake as part of the nutrition screening process.

FAQ- Fiber Math on the Fly

1. How much fiber is too much fiber to consume in a day?

Everything is great in moderation and this applies to fiber as well. There is no doubt that fiber is extremely good for us however, too much fiber can cause bowel disturbances and other uncomfortable feelings.

Dieticians do not recommend consuming a large amount of fiber suddenly or in a short period. If your diet is low in fiber, increasing it suddenly may cause more harm than good. It is best to do it slowly and steadily. Doctors suggest that you do not eat more than 70 grams of fiber per day. 

Adverse effects of fiber include bloating, gas, and even cramping. Aim to eat between 21 to 70 grams of fiber each day.

2. Are 5 grams of fiber good?

When you are checking to see whether or not a food is high in fiber, it is always good to check the label. In most cases, the nutritional information on the back mentions the fiber content of any food. However, if you are consuming natural sources of fibers like fruits, vegetables, and nuts, looking up their fiber content on the internet is a good idea. 

Generally, if something is considered a good source of fiber, it has around 2.5 to 2.9 grams of fiber-packed into a single serving. Additionally, if something contains 5 grams of fiber, it is an excellent source of fiber and must be an essential part of your diet. 

The best way to incorporate fiber-rich food into your diet is by consuming whole grain products. This is because these options usually have 2 to 3 grams of fiber and are hence an excellent source of fiber. 

Whole fruits are also a great source of fiber and must be eaten regularly.

3. What foods are considered high in fiber?

If you are looking to incorporate high fiber foods into your diet then there are a lot of options for you to choose from. All of these can help sneak some fiber into your diet without you having to make any drastic changes. 

Some natural fibers that can help boost your fiber intake are listed here:

  • Vegetables such as broccoli, carrots, potatoes avocados, and more eaten as salads
  • Fruits such as apples, bananas, raspberries, and other berries are eaten whole
  • Different wholegrain products such as pasta, bread, and more
  • Dried fruit
  • Beans such as lentils and others in the form of soups and stews
  • Snacks such as popcorns
  • Nuts can be eaten as a snack 

4. How to calculate the amount of fiber needed in one’s diet?

Although there is a recommended amount of fiber adults must consume, it is a fact that no two humans are the same. Everyone differs in height and weight so it may be quite useful to calculate how much fiber each person needs in a day. According to the amount fo food they consume, everyone’s needs different amounts of fiber to stay healthy and not feel the harmful effects of a low fiber diet.

Dieticians recommend that for every 1000 calories that one consumes in a day, 14 grams of fiber must be consumed. This would mean that if one consumes a total of 2000 calories a day, 28 grams of fiber must be consumed. 

Hence, this is a very easy way to calculate how much fiber you need in a day. You can also check whether or not you are eating enough fiber depending on the amount of food you eat per day.


Having enough fiber in one’s diet is extremely important. However, how do we know whether or not we are eating enough fiber? The answer is very simple and the method detailed in this article has listed exactly how to calculate your fiber uptake so you can remain vigilant and healthy.