Fiber Intake Calculator

Why does dietary fiber matter?

Dietary fiber is the indigestible portion of plant foods. It plays a critical role in digestive health — promoting regular bowel movements, feeding beneficial gut bacteria, and slowing glucose absorption. Higher fiber intake is consistently associated with lower risk of heart disease, type 2 diabetes, colorectal cancer, and obesity. Most adults in Western countries consume only 15–17g per day, well below recommendations.

How much fiber do I need per day?

The American Heart Association recommends 14g of fiber per 1,000 calories consumed. The Academy of Nutrition and Dietetics gives specific targets by age and sex: men under 50 need 38g/day; women under 50 need 25g/day; men over 50 need 30g/day; women over 50 need 21g/day. These targets reflect that calorie needs decrease with age.

Soluble vs insoluble fiber — what's the difference?

Soluble fiber dissolves in water to form a gel-like substance. It helps lower blood cholesterol and glucose levels. Good sources include oats, beans, apples, and citrus. Insoluble fiber adds bulk to stool and helps food move through the digestive system. Found in whole grains, nuts, and vegetables. Most plant foods contain a mix of both types.

Can I eat too much fiber?

Very high fiber intake (above 70g/day) can cause digestive discomfort including bloating, gas, and constipation, especially if increased rapidly. It can also reduce absorption of some minerals. Increase fiber intake gradually over several weeks and drink plenty of water to avoid these effects.