Dietary Fiber, Energy Intake and Food Consumption

Dietary fiber contributes to greater food quantity without simultaneous increase of energy intake. Therefore dietary fiber favours a low energy density of food items associated with a high satiating effect. Accordingly diets rich in dietary fiber are recommended for obesity treatment to accomplish more easily hypocaloric food intake in conjunction with maintenance of satiety. It is the intention of the present study to examine whether or not greater fiber intake in daily nutrition contributes to a reduced energy intake in obese and normal weight subjects. METHODS Dietary protocols of 480 obese and normal weight subjects were analyzed and ranked intraindividually on the basis of daily fiber intake. RESULTS With increasing dietary fiber intake energy density of all daily consumed food items was significantly lower while food quantity and energy intake increased significantly. Reduction of energy density was − 14.5 % while food quantity increased by + 47.9 % resulting in a rise of energy intake of + 30.5 %. The increase of food quantity was primarily due to food items with low energy density (+ 60.9 %) while those with high energy density contributed 25.2 % only. With regard to energy intake food with high energy density contributed most. The most important food groups were bread, fruits, vegetables, carbohydrates such as rice, pasta and potatoes, butter, sausages and chocolate. CONCLUSION The present data demonstrate that high intake of dietary fiber does not automatically reduce energy intake since increased fiber intake is tightly connected with greater food quantity. A favourable effect of dietary fiber can be obtained in processed food such as bread where fiber can replace energy containing components such as flour. This would result in lower energy density. Therefore in obesity treatment it is more reasonable to focus on energy density rather than on daily fiber intake.