Carbohydrate Guide
Why fiber matters: benefits of a high-fiber diet
Fiber is a carbohydrate your body can't fully digest — and that's exactly what makes it useful.
Soluble vs. insoluble fiber
Soluble fiber
Dissolves in water and forms a gel-like substance in digestion. Found in oats, beans, apples, and citrus fruit. Associated with improved cholesterol and more stable blood sugar.
Insoluble fiber
Doesn't dissolve, and adds bulk that helps move food through the digestive tract. Found in whole wheat, nuts, and vegetable skins. Associated with regularity and digestive health.
Why it matters
- Digestive regularity — adds bulk to stool and supports normal bowel function
- Cholesterol and blood sugar — soluble fiber in particular is linked to improved cholesterol levels and more gradual blood sugar rises
- Satiety — high-fiber foods tend to be more filling per calorie, which can support weight management
- Gut microbiome health — fiber feeds beneficial gut bacteria
Most adults need roughly 25 grams/day (women) to 38 grams/day (men) under age 50 — and most people fall short of that target.[1]
Keep reading: What carbohydrates actually do · Simple vs. complex carbs · How many carbs per day