Let your food be your medicine, and your medicine be your food. ...Hippocrates
Depending on the composition of the fiber in the food, that is the proportion of pectin, hemicellulose, cellulose or lignin, he nutritional value and physiological effect of dietary fiber foods can vary.
Vegetables harvested at younger growth stage are likely to contain higher pectin and hemicellulose (soluble fibers) and less cellulose and lignin (insoluble fibers) than when harvested at later growth stages. Generally, the concentration of the insoluble fiber components increases with maturity of the vegetable or fruit, where as the reverse is true to the soluble fiber components. Overall, the later the maturity of the vegetable or fruit at harvest time, the higher is the total fiber content.
Dietary fiber can be partly digestible or completely indigestible by the bacteria in the colon. The dietary fiber components that are partly digestible in the colon include pectin, hemicellulose and cellulose. Lignin is not digestible at all by the bacterial enzymes in the colon. Lignin also lowers the digestibility of the other fiber components.
For health benefits of consuming high fiber foods such as fruits, vegetables and cereals, read: Dietaty fiber food and health.
For more lists of foods high in dietary fiber, visit these pages:
Total dietary fiber, soluble fiber, insoluble fiber content of foods (vegetables, fruits, and nuts)
List of low fiber food sources
Dietary fiber: Daily Reference Intakes (DRIs) for fiber
Definitions of dietary fiber food