We’ve all been told to eat more fiber, but it often feels like the unglamorous part of nutrition. In reality, dietary fiber is one of the most powerful tools we have for steady energy, easier weight management, and a resilient immune system.
Put simply, dietary fiber is a type of carbohydrate found in plants that your body can’t fully break down. Because it passes through you relatively untouched, it doesn’t add calories — instead, it acts as a "workout" for your digestive system and a feast for your gut microbiome.
What Exactly is Dietary Fiber?
Think of fiber as the structural "skeleton" of plants. You’ll find it in fruits, vegetables, whole grains, beans, and pulses. On a technical level, it's made up of compounds like inulin, lignin, and resistant starches.1
To keep things simple, we usually group fiber into two categories:
Soluble fiber: Dissolves in water to form a gel-like substance. It’s great for slowing down digestion (keeping you full) and managing cholesterol. Insoluble fiber: Doesn’t dissolve, but adds "bulk" to your food and helps everything move through your digestive system regularly.
The real-world benefits of a diet high in fiber
Fiber does a lot more than just "keep things moving." Here is how it impacts your daily health:
Crush cravings: Fiber slows the speed at which food leaves your stomach. This prevents blood sugar spikes and crashes, helping you stay satisfied for hours rather than reaching for a snack at 10 am.1 Heart health: High-fiber intake (especially from oats and grains) is linked to better cholesterol levels and lower blood pressure.2,3 Weight management: Because high-fiber foods are often more voluminous but lower in calories, they help you feel physically full on less food.1,4 Immune support: Around 70% of your immune system lives in your gut. Soluble fiber feeds the "good" bacteria (bifidobacteria) that help your body fight off illness.5
How much fiber do I need?
In the US, the goal for most adults is14g for every 1000 calories consumed, though many of us currently only manage about 18g total.
Tip: If you’re planning to increase your intake, do it gradually over two weeks and drink plenty of water. Jumping from 10g to 30g overnight can lead to some temporary bloating!
28 high-fiber foods to add to your shopping list
You don’t need fancy supplements to hit your goals. Here are 28 everyday staples that pack a punch: The Staples The Veg Drawer The Fruit Bowl Snacks & Seeds Oats & barley Broccoli & cauliflower Apples & pears Almonds & walnuts Brown rice Potatoes (keep the skins on!) Raspberries & blackberries Chia & flaxseeds Quinoa Brussels sprouts Bananas Popcorn (plain) Lentils & chickpeas Artichokes Oranges Pumpkin seeds Kidney beans Cabbage & celery Avocado Peanut butter
Common questions about fiber
Does cooking vegetables reduce their fiber content?
Generally, no. While cooking can change the type of fiber or make it softer, the total amount of fiber usually stays the same. Some vegetables (like carrots) actually provide more accessible nutrients when cooked.
Can I get enough fiber on a low-carb diet?
Yes, but make it a priority. Focus on leafy greens, cauliflower, chia seeds, and avocados, which provide high fiber with very few net carbs.
What is "resistant starch"?
This is a type of fiber that forms when foods like potatoes or rice are cooked and then cooled. It’s incredibly beneficial for gut health as it "resists" digestion and ferments in the large intestine.
Take Home Message
Fiber isn't just a dietary "extra" — it’s a foundational part of feeling good. By swapping refined grains for whole versions and adding an extra handful of berries or beans to your meals, you can bridge the fiber gap and support your gut health with very little effort. Win, win.
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Claire is a Registered Dietitian through the Academy of Nutrition and Dietetics and a board-certified Health and Wellness Coach through the International Consortium for Health and Wellness Coaching. She has a Bachelor of Science in Biology and a Master’s degree in Clinical Dietetics and Nutrition from the University of Pittsburgh.
Talking and writing about food and fitness is at the heart of Claire’s ethos as she loves to use her experience to help others meet their health and wellness goals.
Claire is also a certified indoor cycling instructor and loves the mental and physical boost she gets from regular runs and yoga classes. When she’s not keeping fit herself, she’s cheering on her hometown’s sports teams in Pittsburgh, or cooking for her family in the kitchen.
Find out more about Claire’s experience here.
- Anderson, J. W., Baird, P., Davis, R. H., Ferreri, S., Knudtson, M., Koraym, A., … & Williams, C. L. (2009). Health benefits of dietary fiber. Nutrition reviews, 67(4), 188-205.
- Liu, S., Stampfer, M. J., Hu, F. B., Giovannucci, E., Rimm, E., Manson, J. E., … & Willett, W. C. (1999). Whole-grain consumption and risk of coronary heart disease: results from the Nurses’ Health Study. The American journal of clinical nutrition, 70(3), 412-419.
- Brown, L., Rosner, B., Willett, W. W., & Sacks, F. M. (1999). Cholesterol-lowering effects of dietary fiber: a meta-analysis. The American journal of clinical nutrition, 69(1), 30-42.
- Anderson JW . Dietary fiber and associated phytochemicals in prevention and reversal of diabetes. In: Pasupuleti VK Anderson JW, eds. Nutraceuticals, Glycemic Health and Type 2 Diabetes. Ames, Iowa: Blackwell Publishing Professional; 2008:111–142.
- Vos, A. P., M’rabet, L., Stahl, B., Boehm, G., & Garssen, J. (2007). Immune-modulatory effects and potential working mechanisms of orally applied nondigestible carbohydrates. Critical Reviews™ in Immunology, 27(2).
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