The form of food may or may not affect its fiber content. Canned and frozen fruits and vegetables contain just as much fiber as raw ones. Other types of processing, though, may reduce fiber content. Drying and crushing, for example, destroy the water-holding qualities of fiber. The removal of seeds, peels or hulls also reduces fiber content.
Whole tomatoes have more fiber than peeled tomatoes, which have more than tomato juice.
Likewise, whole wheat bread contains more fiber than white bread. Table 1 lists the dietary fiber content of some common foods. The average American consumes 14 grams of dietary fiber per day. People with high cholesterol levels or diverticulosis may benefit from a diet that contains up to 40 grams per day. For many people this requires major changes in eating habits.