Soluble vs. Insoluble Fiber: What’s the Difference?

This article was written with help from AI and edited by Thrive Market’s talented team of human writers.

Dietary fiber comes in two main types—soluble and insoluble—each with distinct roles in the body. Understanding these differences can help optimize fiber intake for better overall health.

Soluble Fiber: The Gel-Forming Fiber

Soluble fiber dissolves in water, forming a gel-like substance in the digestive tract. This type of fiber can be found in:

• Oats
• Beans and lentils
• Apples and citrus fruits
• Carrots
• Barley
• Psyllium

Potential Health Benefits of Soluble Fiber

• Lowering Cholesterol: Soluble fiber can help reduce LDL (“bad”) cholesterol by binding to bile acids, which are then eliminated from the body.
• Blood Sugar Support: By slowing digestion and sugar absorption, soluble fiber helps reduce spikes in blood sugar levels after meals.
• Gut Health: Some soluble fibers act as prebiotics, feeding beneficial gut bacteria that support digestion and immune function (learn more about prebiotics vs probiotics).​

Recipes With Soluble Fiber

• Carrot Cake Baked Oatmeal: This recipe features oats, grated carrots, apples, and raisins for natural sweetness.
• Mung Bean Pancakes: A traditional Korean dish made with blended mung beans, carrots, zucchini, mushrooms, and scallions, then pan-fried until golden.
• Red Lentil Soup: Cozy, comforting, and simple, this recipe is easy to double or triple to make ahead and freeze for later.

• Pinto Bean Salad: Beans are tossed with onion, garlic, olive oil, white wine vinegar for a vibrant side.
• Toast With Almond Butter, Apples, Sea Salt, and Thyme: This gourmet toast features elevated ingredients for a nourishing snack.

Insoluble Fiber: The Bulking Fiber

Insoluble fiber does not dissolve in water. Instead, it adds bulk to stool, helping food pass more quickly through the digestive system. Foods with insoluble fiber include:

• Whole wheat and bran
• Nuts and seeds
• Vegetables (e.g. cauliflower, green beans, and potatoes)
• Brown rice

Potential Health Benefits of Insoluble Fiber

• Preventing Constipation: By increasing stool bulk and promoting regularity, insoluble fiber helps prevent constipation and keeps the digestive system running smoothly.
• Supporting Satiety: Insoluble fiber promotes fullness by slowing digestion and increasing satiety.​

Recipes With Insoluble Fiber

• Brown Rice and Lentil Salad: This hearty salad features dried cranberries, pistachios, and lots of fresh herbs.
• Brown Rice and Salmon Salad: Use leftover brown rice as a base for this Japanese-inspired salad paired with salmon and edamame.
• Pistachio Pesto: Elevate your eggs or toss your next bowl of pasta with this flavorful and nutty pesto.
• Whole-Roasted Cauliflower: Coated in a tangy mustard sauce, this recipe will make cauliflower the star of your next meal.
• Green Bean and Hazelnut Salad: For a nourishing side, give green beans (and crunchy nuts) a try.

Which Type of Fiber Is Best?

Both types of fiber are essential for good health, and a well-balanced diet should include both.

How Much Fiber Do You Need?

The amount of fiber you need daily will be different for each person. In the 2025 Dietary Guidelines for Americans, the USDA recommends the following dietary fiber goals for adults:

• Men (19-30): 34 grams
• Men (31-50): 31 grams
• Men (51+): 28 grams
• Women (19-30): 28 grams
• Women (31-50): 25 grams
• Women (51+): 25 grams​

Tips for Increasing Fiber Intake

• Choose whole grains over refined grains.
• Add beans, lentils, and vegetables to meals.
• Snack on nuts, seeds, and whole fruits.
• Incorporate high-fiber cereals into breakfast.