Fiber helps pull water from the colon, making the stool softer and easier to pass. So if you're often constipated, eat a fiber-rich diet.
The other extreme is diarrhea, which happens when there is too much water in the colon. Again, fiber can help get your system back in order.
“Soluble fiber can actually absorb excess fluid in the bowel and thus act to firm up a loose stool. Think of it as a sponge effect,” Goldstein says.
How Much Fiber Do You Need?
The average American eats 15 grams of fiber per day, but they should get much more than that, the Academy of Nutrition and Dietetics says. The academy recommends 25 grams for women and 38 grams for men.
Add more fiber to your diet slowly to avoid cramps and bloating; do it over a 2-3 week period and drink plenty of water. “Start by adding 7 grams of fiber to your daily diet and increase it each week until you are at the goal of 25-38 grams of fiber daily,” says Megan Davis, RD, LD. She's a dietician at the University of Alabama’s EatRight program in Birmingham.
To reach her daily target, a woman could eat:
A cup of oatmeal (4g) and a pear (4g) for breakfast
A large apple for a snack (4.5g)
A salad made with 3 cups of romaine lettuce (3g), ¼ cup of chopped celery (2g), and a small tomato (1.4g) with lunch
Half a cup of cooked spinach (7g) as a side dish with dinner
A man could reach that target by adding three dried figs (10.5g) and a medium-sized baked yam (6.8g) to his dinner.