The researchers tested nine diets on 17 volunteers for two weeks at a time. They measured how much carbohydrate, fat, protein, fiber and energy (calories) the volunteers used from the diets--nine combinations of low, medium and high fat with low, medium and high fiber. Dieticians increased the fiber intake by adding breakfast cereal, carrot and celery sticks, tossed salads, canned and fresh fruits, cookies, nuts and sunflower seeds to the menu.
Overall, increasing the fiber intake decreased the digestion and absorption of both fat and protein, the researchers reported in the Journal of Nutrition (127, pp. 579-586). As a result, available calories decreased as fiber increased. Based on actual measurements, the researchers estimate that if U.S. men doubled their daily fiber intake from an average 18 grams to 36 grams--the highest amount used in this study--they would absorb about 130 fewer calories per day. For women, doubling fiber intake from 12 to 24 grams a day would reduce absorption by 90 calories.
in conclusion, according to this study, eating the recommended 35 grams of fiber a day blocks about 245 calories a day in women. nice. :-)