Snacking on foods with soy protein, such as edamame beans, can help lower blood cholesterol. JOHN DZIEKAN/ASSOCIATED PRESS

Find out how much fiber is enough and whether soy is a miracle food

Date published: 8/20/2006

Readers want to know how much fiber is enough, and whether soy is worth eating.

Q I know we need 25 to 35 grams of fiber a day. But how does a person determine what is exactly right? Is there an age or weight variable? What is the drawback to getting too much fiber?

--J.L., King George

AEating more fiber can help you avoid constipation and diverticulitis. It even reduces cholesterol levels and the risk of diabetes, according to the National Academy of Sciences.

People who eat more fiber are more likely to be normal weight than overweight, according to a study in the Journal of the American Dietetic Association this summer.

And healthy people who ate more than 35 grams of fiber daily for a year had better digestion. They reported less constipation and heartburn and no worse symptoms of gas and bloating than their peers. That's according to the Women's Healthy Eating and Living Study.

Talk with your doctor about fiber if you have digestive problems.

Generally, babies are the only people who don't need fiber. Breast milk has everything newborns need, and it doesn't have fiber. When a baby reaches 6 months old and starts eating solid foods along with breast milk (or formula), it's good to offer pureed vegetables and fruits, which have some fiber.

Children and adults need about 14 grams of fiber for every 1,000 calories they eat, which translates to 25 to 38 grams for most adults. National surveys show Americans eat half that amount.

If people choose high-fiber foods and adjust portions to their hunger level, they will naturally get enough fiber, without counting or doing math.

If that's too vague for you, aim for about two fist-size portions of high-fiber foods per meal. Whole grains, fruits, vegetables, beans and nuts are all rich in fiber.

Remember that refined foods like white bread, white rice, regular pasta, mashed potatoes, juice and sweets are low-fiber foods, so don't overdo them.

Balance your meal with a palm-size portion of low-fiber but protein-rich food, such as meat, chicken, fish, eggs, cheese, yogurt, milk or soy.

It's hard to overdo fiber from foods, so the National Academy of Sciences has not set any limits on fiber.

JENNIFER MOTL is a registered dietitian. Formerly of Fredericksburg, she now lives in Wisconsin.

Date published: 8/20/2006