Fiber intake and long term weight gain.




Am J Clin Nutr

Related Monographs

Consumer Data: Fiber Obesity, Weight Loss
Professional Data: Fiber Obesity, Weight Loss


Dietary fiber is a general term that refers to a wide variety of compounds found in plants that are resistant to the digestive enzymes produced by humans. Because dietary fiber is resistant to digestive enzymes, it is not broken down or absorbed, which means it does not provide calories or energy to the body. In general, dietary fibers are various forms of complex carbohydrates that have differing abilities to swell by absorbing water into their structural matrix.

A lack of fiber is usually the result of poor food choices, which results in a diet that is deficient in fiber-containing foods. Consuming a diet lacking in fiber increases the risk of developing gastrointestinal problems such as constipation, diverticular disorders, and alterations in glycemic control. It has been recommended that Americans should strive to achieve a total dietary fiber intake of 25 to 30 grams/day, which should preferentially come from foods, not supplements. However, dietary surveys indicate that dietary fiber intake among adults in the United States averages about 15 grams/day, or approximately half the recommended amount.1

A recent study published in the American Journal of Clinical Nutrition established that dietary intake of fiber is important in maintaining healthy body weight. This study investigated the intakes of different types of grain products and long-term weight gain. Over 74,000 healthy female participants were followed from 1984 to 1996. The dietary habits were recorded in 1986, 1990, and 1994. The researchers also calculated the Body Mass Index (BMI), odds of developing obesity, and weight changes in these women. The results showed that women who consumed more whole grain products generally weighed less that those who consumed less whole grain products. Those with the highest intake of whole grain products had a 49% less risk of weight gain. The authors concluded that, “Weight gain was inversely associated with the intake of high-fiber, whole-grain foods but positively related to the intake of refined-grain foods.”2


1. Alaimo K, McDowell M, Briefel R, Bischof A, Caughman C, Loria C, Johnson C. Dietary intake: vitamins, minerals and fiber of persons age two months and over in the United States: third National Health and Nutrition Examination Survey: phase 1, 1988-91. Advance Data. 1994;258:1-28.
2. Liu S, et al. Relation between changes in intakes of dietary fiber and grain products and changes in weight and development of obesity among middle-aged women. Am J Clin Nutr. Nov 2003;78(5):920-7.