Results demonstrated that fewer calories wer e absorbed with increased fiber intake. When a man increased his fiber intake from 18 to 36 grams per day, he absorbed 130 fewer calories daily. When a woman increased her fiber intake from 12 to 24 grams per day, she absorbed 90 fewer calories daily. However, having too much fiber in one's diet can cause problems. When the intake of fiber is too high, it can replace other energy and nutrients that you need in your diet.
Some insoluble fibers bind certain minerals, including calcium, magnesium, phosphorous, and iron.
So, go slowly to give your GI tract time to adapt and drink lots of fluids to keep the fiber soft. Overall, fiber is a good thing. Hope this was helpful.