What Happens If You Have Too Little Fiber in Your Diet?

Medically Reviewed on 11/17/2021
If you are not getting enough fiber through your diet, your body will exhibit clear warning signs like constipation and hemorrhoids.
If you are not getting enough fiber through your diet, your body will exhibit clear warning signs like constipation and hemorrhoids.

If you are not getting enough fiber through your diet, your body will exhibit clear warning signs. Read more to learn about 4 warning signs your diet may lack fiber.

What is fiber, and what does it do for your body?

Fiber is a carbohydrate that your body is not able to digest. While typically carbohydrates get converted into sugar by your body, fiber does not. Instead, fiber passes through your digestive system undigested. It is a crucial element in your body’s ability to stabilize your blood sugar and keep your hunger in check. Fiber also plays a role in your digestive system. Without it, your digestive system ceases to work as it should.


One clear sign that your diet lacks fiber is that you are constipated. Constipation is when you have less than three bowel movements per week. It occurs when your digestive system doesn’t move waste quickly enough through your system.

If this happens, your colon will absorb the water from your waste, and the waste will dry out. Once it dries out, it will become difficult to push the waste out of your body.

Fiber helps your waste move through your body quickly and efficiently. One of the first treatments for constipation your doctor may prescribe for you is slowly adding more fiber to your diet. Usually, fiber comes from fruits, vegetables, and whole grains. You can also take fiber supplements. However, be careful not to add too much fiber at once; this can cause an adverse reaction and make you even more constipated.


A hemorrhoid is a swollen vein in your anus or rectum. They can happen inside of your rectum or outside on the skin around your anus. Symptoms of hemorrhoids include:

  • Itching
  • Pain
  • Swelling
  • Bleeding
  • Bleeding during bowel movements
  • Severe pain
  • Inflammation
  • Lumps around the anus

Hemorrhoids can often be a sign that you do not have enough fiber in your diet. To prevent hemorrhoids, you want your stool to have a soft texture so that it can move smoothly through your body. Eating high-fiber foods such as fruits and vegetables and possibly taking fiber supplements is one of the best ways to prevent hemorrhoids.

Weight gain

Foods with high fiber take longer to eat. This may make you feel full and satisfied without eating higher volumes of food. For example, eating broccoli (a high-fiber food) will likely involve more time and more chewing than eating a large serving of french fries.

Additionally, most high-fiber foods are packed with nutrients yet low in calories. Due to the efficient nature of a high-fiber diet, weight loss might be an added benefit to increasing your fiber intake.


According to the USDA, there is no difference between a “portion” and a “serving.” See Answer

Irritable bowel syndrome

Irritable bowel syndrome (IBS) is linked to not getting enough fiber. Some signs you have IBS are:

A popular treatment for IBS is to add more fiber to your diet. However, specifically with IBS, this can be a double-edged sword. It has been found that certain types of fiber or high-fiber foods can exacerbate symptoms of IBS; an example of food like this would be bran. 

Based on your symptoms, your doctor may prescribe certain high-fiber foods. These symptoms include:

  • Lower abdominal pain. If you have pain in this region, your doctor may tell you to incorporate fiber into your diet by eating psyllium. Psyllium is a soluble fiber found in a specific shrub-like herb. You can find it in a format suitable for eating in dry seeds and husk forms. You can also find it in supplements through capsules, tablets, wafers.
  • Upper abdominal pain. Eating oatmeal, oat, bran, or psyllium might help you if you experience pain in your upper abdominal region. 
  • Constipation. It may be helpful to take a laxative containing methylcellulose or eat psyllium to ease constipation. 
  • Incomplete evacuation. Like constipation, if you are experiencing incomplete evacuation, you may want to take a methylcellulose laxative or eat psyllium. 
  • Diarrhea. If you are experiencing diarrhea, you want to increase your fiber intake by eating psyllium or foods with a high amount of oligofructose. Oligofructose is a natural compound that can be found in many foods such as chicory root, raw dandelion greens, dried garlic, and bananas.
  • Gas. If you are experiencing gas in excessive or intense amounts, incorporate methylcellulose or polycarbophil. The best way to take both of these compounds is through laxatives. 

Health Solutions From Our Sponsors

Medically Reviewed on 11/17/2021

Cleveland Clinic: “Constipation,” “5 Simple Ways You Can Prevent Hemorrhoids.”

Harvard T.H. Chan: “The Nutrition Source.”

healthywomen: “Signs You’re Not Getting Enough Fiber.”

Mayo Clinic: “Hemorrhoids.”

Mount Sinai: "Psyllium."

The Journal of Nutrition: “Presence of Inulin and Oligofructose in the Diets of Americans.”