londonjulz I found this out a week ago from my sil she is a nutritionist.
Hopefully I don't mess this up but this is what she told me..
Your body naturally burns x amount of calories mine is about 1800, this comes from thinking, breathing etc..My sil says that about 40% of that comes from digesting food, so she recommended that I actually get my fiber from food because fiber from food takes my body that much more energy (calories) to digest then any other food/nutrient there for I would burn some extra calories.
Did you get that or did I completely confuse you..hehe
Obviously fiber from any source is better then none, but whenever I can cheat and get some extra calories off I do