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Is Fiber Effective for Weight Loss? 
Updated on January 31, 2024
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Is Fiber Effective for Weight Loss? 

Fiber is an essential component of your diet. Adults need at least 25 to 35 grams daily to maintain good health. Unfortunately, most Americans eat only 15 grams of fiber each day.1 

Getting enough fiber allows healthy people to maintain a normal weight. However, for people struggling with their weight, consuming adequate fiber may aid in weight loss.

We asked registered dietitian Elise Harlow to help us explain how fiber promotes healthy weight loss.

Is Fiber Effective for Weight Loss?  2

How Does Fiber Help You Lose Weight?

Here are seven ways that fiber promotes weight loss:

1. Fills You Up Without the Calories

Fiber is a carbohydrate found in many plant-based foods. But unlike most carbs, your body is unable to digest and convert them into glucose for energy.

It passes through most of the gut intact and provides little to no calories.1 You can eat as much as you like without worrying about your calorie intake.

Fiber is helpful for weight loss because it allows you to eat fewer calories than what you’re used to without having to deprive yourself of food.

2. Keeps You Satisfied

Foods high in soluble fiber—such as apples, beans, and oats—slow gastric emptying or the passage of food from your stomach to your intestine.2

Since food stays longer in your stomach, you will feel full for longer periods. This increased satiety can decrease the amount of food you eat in a day.

3. Makes You Feel Less Hungry

Foods with insoluble fibers like almonds, kale, and wheat bran have little effect on the movement of food across your digestive tract.

However, they’ve been shown to reduce appetite.3 Eating insoluble fibers will make you feel less hungry and decrease your food intake throughout the day.

4. Creates a Calorie Deficit

Calories provide energy for your body and support its daily function. When you eat fewer calories than what you need, it leads to a calorie deficit.

Calorie deficiency encourages your body to burn stored fats for energy instead of depending on the food. This leads to the loss of fat and weight reduction. 

Fiber helps you achieve this state by:

  • Increasing your satiety
  • Curbing your appetite
  • Decreasing your food intake
  • Reducing your overall calories

5. Slows Food Metabolism

Food is broken down into glucose for energy. But when there’s too much sugar in the blood, your body stores the excess energy as fat—leading to weight gain.

Fiber slows digestion and prevents glucose from being released too quickly into the bloodstream. 

Besides controlling your blood sugar levels and lowering your risk for type 2 diabetes, this keeps you from gaining weight.

Soluble fibers decrease the absorption of macronutrients like carbohydrates, proteins, and fats in your digestive tract.2 

Insoluble fibers are fermented by your gut bacteria into short-chain fatty acids, which decreases the rate at which your body converts food into glucose.3

6. Promotes Long-Term Weight Management

Many weight loss diets can help you lose weight. Low-carb dieting, intermittent fasting, and the ketogenic diet are just a few examples.

But according to Elise Harlow, M.S., R.D.N., calorie-restricted diets often leave you hungry, which prevents you from sticking with the dietary changes.

For this reason, some researchers believe that a person’s ability to stick to a diet (adherence) is more important for weight loss than the type of diet used.4

Studies show fiber encourages dietary adherence in obese and overweight adults who follow calorie-restricted diets.5

“By keeping you full, fiber can help you focus on what to eat more of (fiber) instead of what you need to cut out from your diet,” Harlow explains.

7. Supports a Healthy Gut Environment

Soluble fibers act as a natural food source for beneficial gut bacteria. They can inhibit the growth of harmful bacteria by nourishing healthy microbes to grow.

Fiber supplements can shift your gut microbiome in favor of Bacteroides, a type of gut bacteria linked to weight loss.6

Studies show that people with more Bacteroides than Firmicutes tend to be leaner, while those with a higher Firmicutes ratio tend to be more obese.6

This is because Firmicutes digest carbs and fats more efficiently than Bacteroides, which leads to the development of obesity.7

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What Are Some Good Sources of Dietary Fiber?

Most nutritionists agree that whole foods are excellent sources of dietary fiber. This includes fruits, vegetables, nuts, legumes, and whole grains.

Whole foods rich in fiber—unlike processed foods with added fiber—also provide essential vitamins, minerals, and other nutrients

There are two kinds of fiber: soluble and insoluble fibers. Both can help with weight loss. Below are some examples of foods where you can get these fibers:

Foods High in Soluble Fiber

Soluble fibers dissolve in water and form into a gel-like substance. 

They help you lose weight by slowing your digestion, keeping you full, and promoting a balanced gut microbiome.

Some good sources of soluble fiber are:

  • Apples
  • Barley
  • Beans
  • Carrots
  • Citrus fruits
  • Oats
  • Peas
  • Psyllium

Foods High in Insoluble Fiber

Insoluble fibers do not dissolve in water. They promote weight loss by reducing your appetite so you’re less likely to eat sooner than your next meal.

Some good sources of insoluble fiber are:

  • Cauliflower
  • Green beans
  • Nuts
  • Potatoes
  • Wheat bran
  • Whole wheat flour

Can I Get Fiber from Health Supplements?

While it’s best that you consume fiber-rich foods, getting fiber from supplements is better than not having any fiber at all.

A fiber supplement is an alternative source of fiber and may contain soluble fiber, insoluble fiber, or a combination of both (like psyllium). 

If you don’t get enough fiber from food, you can take them to supplement your daily requirements. Common fibers that are added to these supplements are:

  • Calcium-polycarbophil
  • Coarse wheat bran
  • Flaxseed
  • Methylcellulose
  • Psyllium husk

Do Fiber Supplements Also Help With Weight Loss?

Fiber supplements can help you lose weight. Data collected from 62 studies show that consuming 7 grams of viscous (soluble) fiber for ten weeks can:8

  • Decrease your weight by three-quarters of a pound
  • Reduce your waist circumference by a quarter

Researchers also found that weight loss was more significant in people who were overweight or had diabetes than in healthy people.8

In another study involving 118 overweight adults, participants were either given rice flour or a fiber supplement for twelve weeks.9

Fiber supplementation reduced the frequency of meals and food intake, resulting in a greater reduction in body weight and body mass index (BMI).9 

Is it Safe to Take Fiber Supplements for Weight Loss Every Day?

Yes. Fiber supplements are generally safe to consume. There is currently no evidence that daily fiber supplementation is harmful to your health.10

However, it’s best that you talk to a doctor before you start taking any dietary supplement. They can help make sure it’s safe for you.

When taking fiber supplements, remember to follow the instructions on the nutrition label. Watch out for possible side effects like bloating or gas.

If your symptoms don’t go away or get worse, you should inform your doctor.

How Much Fiber Do You Need Per Day to Lose Weight?

Eating at least 30 grams of fiber per day has been shown to promote weight loss in adults with metabolic syndromes.11

People who are overweight or obese or have high blood pressure, high blood sugar, or high blood cholesterol fall under this category.

In the study, participants were either asked to follow a high-fiber diet or the diet recommended by the American Heart Association (AHA) for twelve months.

High Fiber DietAmerican Heart Association (AHA) Diet
RecommendationsEat 30 grams or more of fiber each dayEat high-fiber foods, fruits, vegetables, fish, and lean proteins
RestrictionsNoneCut back on sugar, salt, alcohol, and fat
Average weight loss2.1 kg2.7 kg

Based on the study, you can lose up to 2.1 kg of weight in twelve months by just increasing your fiber intake to 30 grams per day.11

Harlow cautions readers to be careful with their fiber intake:

“It is important to note that while most people would benefit from increasing their intake of fiber, doing so too rapidly can result in stomach discomfort and other stomach issues."

She recommends slowly increasing your fiber intake and drinking more water.

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Updated on January 31, 2024
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11 sources cited
Updated on January 31, 2024
  1. The Nutrition Source: Fiber.” Harvard T.H. Chan School of Public Health.

  2. Effects of Dietary Fiber and Its Components on Metabolic Health.” Nutrients, National Center for Biotechnology Information.

  3. Insoluble cereal fiber reduces appetite and short-term food intake and glycemic response to food consumed 75 min later by healthy men.” American Journal of Clinical Nutrition, Oxford University Press.

  4. Strategies to Improve Adherence to Dietary Weight Loss Interventions in Research and Real-World Settings.” Behavioral Sciences, National Center for Biotechnology Information. 

  5. Fiber Intake Predicts Weight Loss and Dietary Adherence in Adults Consuming Calorie-Restricted Diets: The POUNDS Lost (Preventing Overweight Using Novel Dietary Strategies) Study.” The Journal of Nutrition, PubMed.

  6. Shift in gut bacteria observed in fiber supplement study may offer good news for weight loss.” Consumer and Environmental Sciences, ScienceDaily.

  7. The Influence of Probiotics on the Firmicutes/Bacteroidetes Ratio in the Treatment of Obesity and Inflammatory Bowel disease.” Microorganisms, National Center for Biotechnology Information.

  8. Can a Certain Type of Fiber Help with Weight Loss?” American Institute for Cancer Research.

  9. Effect of Fibre Supplementation on Body Weight and Composition, Frequency of Eating and Dietary Choice in Overweight Individuals.” Nutrients, National Center for Biotechnology Information.

  10. I find it difficult to eat enough fruits and vegetables. Is there any harm in taking a fiber supplement every day?” Nutrition and Healthy Eating, Mayo Clinic.

  11. Single-Component Versus Multicomponent Dietary Goals for the Metabolic Syndrome.” Annals of Internal Medicine. 

Elise Harlow
Elise Harlow, M.S., R.D.N.
Medical Reviewer
Elise Harlow is a registered dietitian with a Master of Science in Nutritional Sciences. She is the founder of an online nutrition consulting and coaching business.

Elise helps people use the power of food to lead healthier lives. She works with various clients, including those who want to achieve a healthier weight, improve their gut health, lower cholesterol, manage their blood sugar, or balance their hormones.
Ada Sandoval
Ada Sandoval
Content Contributor
Ada Sandoval is a B.S. in Nursing graduate and a registered nurse with a heart for abandoned animals. She works as a content writer who specializes in medical-related articles and pet health.
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