Getting Started With Fiber

How to increase fiber intake safely comes down to pace: add one high fiber food a week, eat it daily and drink water alongside it. In three bean feeding studies, reports of extra gas from pinto beans fell from 50% in the first week to 6% in the second.

The main increase fiber side effects are gas, bloating, cramps and changes in stool, and they come mostly from speed and too little water. In a trial of 117 adults on the same high fiber diet, those who drank about 2 liters of water a day had more frequent bowel movements and used fewer laxatives.

What happens when you eat more fiber? Meals feel more filling and blood sugar rises more gently from day one, stools get softer and more regular within a week or two, and gas often peaks early before settling. In a 2021 study, fiber-loving Bifidobacterium rose about 1.4-fold after just two weeks of high-fiber meals.