Fiber (Dietary Fiber)

Dietary fiber is a form of carbohydrate that the human digestive system cannot fully break down. There are two main types of fiber: soluble fiber (in oats, legumes, fruits) forms a gel-like mass that slows stomach emptying and stabilizes blood sugar. Insoluble fiber (in whole grain cereals, vegetables) adds bulk to stool and speeds up intestinal transit.

During weight loss, fiber is one of the most underappreciated tools. It significantly increases the volume of food without adding much energy - for example, 200 g of broccoli contains only 70 kcal but fills up a plate. Fiber also slows nutrient absorption, which maintains satiety longer and prevents blood sugar spikes. In studies, simply adding fiber to the diet has led to weight loss without any other changes.

The recommended fiber intake is 25-35 g per day, but the average intake falls below 20 g. Good fiber sources include oatmeal (1 serving = 4 g fiber), whole grain bread (2 g/slice), lentils (8 g/100 g), apple (4 g), and chia seeds (10 g/tablespoon). Practical tip: increase fiber in your diet gradually and drink enough water to avoid digestive discomfort.

Fiber also feeds beneficial gut bacteria, which affects the immune system, mood, and even weight management. Fiber is closely related to carbohydrate quality and gut health.

Last updated: March 30, 2026