One of the few health and nutrition blogs that I still visit is Mark’s Daily Apple. Its author is an evangelist for carnivorism, so I am not a fan, but it is popular and influential enough that it allows one to explore ideas that are liable to come into fashion. Today, it featured a guest post from one Konstantin Monastyrsky: a “credible researcher” who argues that dietary fibre is “a menace to your health”. I wrote a critical, somewhat sarcastic but by no means abusive comment that first hung around in moderation before disappearing. This annoyed me almost as much as the article, so I am going to take a look at it here instead.
I come neither to laud nor damn dietary fibre; being no expert on its benefits or its risks. What I write in opposition to is fearmongering, and Monastyrsky offers this in unwholesome quantities. He writes that advocates of the consumption of fibre have subjected us to “deception“; to “relentless brainwashing“. Those who profit from high-fibre foods, he claims elsewhere, are “squeezing every penny of profit out of [them] for as long as they can weasel their way around the truth”. (He doesn’t name this people, of course. That could be awkward.) Monastyrsk, you see, believes that the harms of fibre are comparable to the harms of cigarette smoking. He believes that it “causes more harm and death than tobacco, alcohol, and illicit drugs combined”.
Scary stuff. Well, do not throw that tub of raspberries into the bin quite yet – still less replace it with a cigarette, a large whisky or a spliff. Let us consider his essay, which takes the form of an attempt to refute various “myths” attached to dietary fibre.
Myth #1: For maximum health, obtain 30 to 40 g of fiber daily from fresh fruits and vegetables.
No one but fruitarians argues that one should consume that much fibre from fruits and vegetables, and there are, for great reasons, very few of them. Even when people recommend that amount of fibre they would expect you to consume legumes, nuts, seeds, whole grains and potatoes as well. Ironically, though, Monastyrsky attempts to knock his own straw man down with a red herring. He lists ten pieces of sugary fruits, the fibre of which comes to a total of about 36 grams. They also contain, in his words, a “whopping 143.6 g of digestible sugars”. Let us assume, as he does, that eating this much is a bad idea (it may not be, for some people, but assume it anyway). What about avocados, berries, aubergine, broccoli, asparagus, spinach, kale, squash, carrots, sweetcorn, peas and turnip greens?
Perhaps to make his misinformation more digestible, Monastyrsky resorts to fearmongering again. “It‘s not surprising that so many Americans are suffering from the ravages of diabetes and obesity,” he writes, implying that people are suffering from illness and weight gain because they are eating apples and bananas. Well, before the guys at Coca Cola, Krispy Kreme and Nestlé breathe easily, let us observe that over two thirds of Americans own up to eating less than two servings of fruit a day. That apple is not giving them diabetes, and when a doctor says it might be a good idea to have a pear as well they are not trying to make them ill, regardless of what Monastyrsky’s surreal cartoon implies.
I did not create this to parody his conspiracism. It is on his website. If someone posts scary drawings along with their arguments it is wise to be careful, lest one’s emotions are being appealed rather than one’s intellect.
Myth #6: Fiber offers protection from breast cancer.
I do not know if this “myth” is true, but Monastyrsky’s attempt to refute it is strange. He claims the “opposite” is true, citing a study of Mexican cancer patients that he argues demonstrates that “women with the highest consumption of carbohydrates, and, correspondingly, of fiber, had the highest rates of breast cancer”.
Turning to the paper, we find that cancer patients ate more carbohydrates than members of the control group but less insoluble fibre (the data for soluble fibre was not given), so Monastyrsky’s assumption is bogus. What they consumed more of was sucrose – table sugar, rarely found in high fibre foods – and fructose – which, given the popularity of juices, honey and agave nectar need not correspond with fibre. The authors, in fact, state that “the strength of the association between sucrose intake and risk for breast cancer was lower among women in the highest tertile of insoluble fiber intake when compared with women in the lowest tertile of insoluble fiber intake”. Monastyrsky has not addressed this supposed “myth”, then, but has simply perpetuated a myth of his own.
Myth #11: Fiber is safe and effective for the treatment and prevention of diarrhea.
Monastyrsky argues that “it’s the complete opposite—fiber, particularly soluble, is the most common cause of diarrhea in children and adults”. Really? Well, stone me. I thought that it was viral gastroenteritis. There I was: washing my hands and cleaning my surfaces to avoid bacteria and viruses and it turns out that I would have been better off saving the water and disinfectants and avoiding berries and lentils. Or not. Monastyrsky does not even try to dress this claim up with a reference.
This may well be for the better, because he twists references to suit his own ideas. In another essay, he tries to dismiss the “willful lie” that dietary fibre is protective against diabetes by offering this quote from the Harvard School of Public Health: “fiber intake has…been linked with the metabolic syndrome, a constellation of factors that increases the chances of developing heart disease and diabetes”. What type of fiber intake has been linked to it, though, and how. If you read the source, it is clear that it is arguing that fibre can be protective against the condition. Indeed, the same website states that “higher fiber intake has also been linked to a lower risk of metabolic syndrome”.
Perhaps few of my readers are sufficiently interested in roughage to have ventured this far through this essay, and I do not blame them. What I hoped to illustrate, however, is a few things to beware of when reading “credible research” that celebrates or demonises this or that food or product: the implication that it contains truths that dark, mysterious forces have struggled to conceal; the quotes and references that can mean very different things when viewed in their rightful contexts; the lavish promises or terrifying threats that transcend the facts of the matter and appeal to one’s emotions. When dealing with fact claims, one must apply standards of objective empiricism. When dealing with health, meanwhile, one should try to avoid stress, and not just as it impairs one’s ability to think. I do not know a great deal about nutrition but I know about obsession and even in small doses it can be harmful.