Everybody is different. Some people tolerate fiber well. Others have gut issues (e.g. diversticulitis, colitis) or overdo it and end up with digestive problems.
From what I've read, the fiber guidelines are basically made-up and not based on any formal nutritional controlled studies. When you think about it, fiber is literally undigestible plant material. It seems a bit strange for your health/body to depend on consumption of something which cannot be digested.
Nothing strange about hunter gatherers evolve eating a lot of fiber. Think about the other extreme, what if you took in all your energy and nutrients through fluids. How well would your bowels work with nothing in them but liquids? I know my bowel movements are much easier after I've eaten some salad than after a low fiber meal.
There's plenty of articles about fiber, here's just a short list I just found.
I'm talking about whether or not they are essential. I eat very little plants and don't have any problems. I also practice fasting from time to time, and I don't have any problems with no food of any kind for days at a time. Go figure.
I've never heard of anyone dying from lack of fiber. Have you? Is there a medical condition for this?
I'm sure that some hunter gatherers ate plants containing fiber. We are omnivores and able to get calories from many different sources depending on availability in our environment. That still doesn't mean that fiber is a necessity or requirement.
"This article reviews the physiology of ingestion of fiber and defecation. It also looks into the impact of dietary fiber on various colorectal diseases. A strong case cannot be made for a protective effect of dietary fiber against colorectal polyp or cancer. Neither has fiber been found to be useful in chronic constipation and irritable bowel syndrome. It is also not useful in the treatment of perianal conditions. The fiber deficit - diverticulosis theory should also be challenged. The authors urge clinicians to keep an open mind about fiber. One must be aware of the truths and myths about fiber before recommending it.
... a strong recommendation cannot be made for a protective effect of dietary fiber against colorectal polyp or cancer. Despite a lack of evidence however, current recommendations are still to increase dietary fiber. In the latest position statement of the American Dietetic Association[3], increasing dietary fiber is still promoted to protect against colon cancer despite stating that there is no proof of efficacy in this regard
...
Whilst it is not the intention of the authors to totally discourage fiber in the diet and the use of fiber supplements, there does not seem to be much use for fiber in colorectal diseases. We, however, want to emphasize that what we have all been made to believe about fiber needs a second look. We often choose to believe a lie, as a lie repeated often enough by enough people becomes accepted as the truth. We urge clinicians to keep an open mind. While there are some benefits of a diet high in natural fiber, one must know the exact indications before recommending such a diet. Myths about fiber must be debunked and truth installed."
Nope. Lack of fiber is not a cause of colon cancer.
A more objective view of the science is:
“...the interactions between meat, gut and health outcomes such as CRC [colorectal cancer] are very complex and are not clearly pointing in one direction... Epidemiological and mechanistic data on associations between red and processed meat intake and CRC are inconsistent and underlying mechanisms are unclear... Better biomarkers of meat intake and of cancer occurrence and updated food composition databases are required for future studies.”
I don't know why you feel so strongly about this subject that you return to it four days later, but she is not an objective expert. She sounds like yet another low carb high fat preacher that wants to sell books, and she makes a flippant remark about how you emit methane after eating beans while "the vegans are blaming the cows". Oh, and she seems to eat plenty of fiber herself:
> I eat fruit most days, but not too much and because I like it, not because I think it is good for me. I eat a lot of vegetables/salads – locally grown/in season wherever possible. [...]. I do eat starchy carbs – just not daily. I enjoy porridge (plain oats and whole milk) – especially in the winter. I like brown rice and (veggie) curries/chilli.
Even if you don't believe in or care about any health benefits fiber may have, two benefits are immediate after eating them: they fill you up and make you feel full without containing any energy which helps mediate calorie consumption, and they make bowel movements easier, at least if you drink enough water. I believe most people would feel better if they ate more fiber instead of red meat and fries.
