Fiber Intake Calculator — How Much Fiber to Eat

Recommended intake depends on sex and age. Men under 50 need about 38 g, over 50 about 30 g. Women under 50 about 25 g, over 50 about 21 g. You can also count about 14 g per 1000 kcal — at 2000 kcal that is about 28 g per day.

Soluble fiber (oats, apples, legumes, flaxseed) forms a gel, slows sugar absorption, lowers cholesterol and feeds gut bacteria. Insoluble fiber (wheat bran, wholegrains, vegetable skins) adds bulk to stool and speeds transit. A healthy diet should include both types.

The best sources are: legumes (lentils, beans, chickpeas — 6–8 g/100 g cooked), wholegrain products (bran, oatmeal, groats, wholemeal bread), vegetables (broccoli, carrots, beets), fruit (raspberries, pears, apples with skin) and nuts and seeds (flaxseed, chia).

Adequate fiber supports regular bowel movements and gut health, helps control blood sugar, lowers LDL cholesterol, increases satiety and feeds gut microbiota. A high-fiber diet is linked to lower risk of heart disease, type 2 diabetes and colorectal cancer.

Yes. Sudden or very high intake (over 50–70 g per day) can cause bloating, gas, abdominal pain, constipation and may even impair absorption of some minerals (iron, zinc, calcium). Increase fiber gradually and drink plenty of water.

Fiber, especially soluble fiber, absorbs water and swells in the digestive tract. Without enough fluids it can cause constipation instead of relieving it. On a high-fiber diet about 2–2.5 liters of water per day is recommended.

Choose wholegrain over refined products, add legumes to meals, eat fruit and vegetables with the skin, snack on nuts and seeds, and add bran or flaxseed to cereal and yogurt. Increase gradually to avoid digestive discomfort.

Yes, children need less fiber than adults — roughly the "age + 5 g" per day rule. Teenagers approach adult norms. This calculator is intended for people aged 14 and over and is based on norms for adolescents and adults.

Supplements (psyllium, inulin) can help fill gaps but do not replace a complete diet — natural foods also provide vitamins, minerals and antioxidants. A supplement can help with constipation or trouble reaching the norm. Take it with plenty of water.

No. The calculator gives indicative values based on general norms and does not account for individual health, gastrointestinal conditions (e.g. IBS, Crohn's disease), pregnancy or medication. If you have symptoms or special needs, consult a dietitian or doctor.