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No, Eating French Fries is Not the Same as Smoking Cigarettes

But excessive consumption of fried foods is a problem, and not only because of the extra calories provided by the fat.

This article was first published in The Montreal Gazette.

I had never heard of psychiatrist Dr. Paul Saladino, which is somewhat surprising because he is quite frisky in the duck pond. His TikTok videos in which he tries to convince his legions of followers that dietary fibre is unnecessary, that drinking beer leads to “man boobs,” that LDL cholesterol does not increase the risk of heart disease, that oatmeal is toxic and the key to health is eating red meat, are laughable.

Saladino’s pseudoscientific rants were brought to my attention by a former student who now teaches science in Germany. He was asked by one of his students about a video in which Saladino claims that eating a serving of McDonald’s fries is equivalent to smoking a pack of 25 cigarettes.

The stimulus for this video seems to be a paper that Saladino read but was unable to properly digest. It discussed similarities between the chemical content of french fries and tobacco smoke and noted that a serving of fries can contain some carcinogenic aldehydes in amounts comparable with that found in the smoke from 25 cigarettes. In no way did the authors suggest that the risks were comparable.

Let’s note right away that there is a big difference between inhaling or ingesting a substance. Inhalation leads to direct entry into the bloodstream, while the digestive tract contains numerous enzymes that metabolize food components.

Next, tobacco smoke contains thousands of compounds, with 62 of these listed by the International Agency for Research on Cancer (IARC) as carcinogenic to humans. The most significant carcinogens in tobacco smoke are not aldehydes, but N-nitrosamines, polyaromatic hydrocarbons, aromatic amines, 1,3-butadiene, benzene and ethylene oxide. While there is no question that carcinogenic aldehydes such as crotonaldehyde can form when fats are heated, the total number of carcinogens that invade a body from a pack of cigarettes are far, far greater than from a serving of french fries.

Of course, the only way to compare the health impact of a daily serving of fries with smoking a pack a day would be to run a long-term study comparing two groups of subjects with the only difference between them being smoking or eating french fries. Clearly, this is impossible to do, but if it were carried out, I would wager that the smoker group would have a far higher incidence of cancer than the french fry group.

Fearmongering has become an industry, and Saladino is a head honcho in this arena. The usual technique is to pick a scientific study that finds some risk and then exaggerate it without taking into account type and extent of exposure. Pesticides, fluoride, oxalates, gluten, lectins and vaccines have all been unrealistically portrayed as villains. This is not to say that there are no legitimate chemical risks. We live in a very complex world, with some 160 million known chemicals, both natural and synthetic. There certainly are issues with some of these. Perfluoroalkyl substances (PFAS), bisphenol A and phthalates are present in just about everyone’s bloodstream and may indeed be causing some serious mischief.

One way or another, we are in contact with thousands of chemicals on a regular basis, and teasing out individual effects is not possible. While french fries may indeed contain some carcinogens, it does not automatically follow that eating them causes cancer. As a classic analogy, coffee contains carcinogens such as furfural, caffeic acid and styrene, but we know that coffee doesn’t cause cancer.

None of this is to say that I am willing to absolve french fries from all blame. Excessive consumption of fried foods is a problem, and not only because of the extra calories provided by the fat. When fats are heated, particularly polyunsaturated seed oils, they form a slew of potentially carcinogenic compounds.

And then there is the issue of the “Maillard reaction,” named after Louis Camille Maillard, physician turned chemist, who in 1912 described the reaction between sugars and amino acids that produces a variety of “melanoidins” responsible for the browning of toast, doughnuts and french fries. In fried potatoes, glucose and the amino acid asparagine undergo a Maillard reaction to yield acrylamide, classified by IARC as a “probable human carcinogen.”

Although associations cannot prove a cause-and-effect relationship, a study by the highly reputable Fred Hutchinson Cancer Research Center in Seattle compared about 1,500 prostate cancer patients with the same number of controls and found that regular consumption, at least once a week, of fried chicken, fried fish, doughnuts or french fries increases the risk of developing the disease.

While carcinogens in fried foods cannot be totally eliminated, they can be significantly reduced. The secret is to do your “frying” in an “air fryer.” These devices have taken kitchens by storm, including mine. Basically, they are small convection ovens in which a current passing through an element heats air that is then circulated by a fan. The basket in which the food is placed has openings to ensure heating from all sides, so covering these with parchment paper or aluminum foil in pursuit of cleanliness is counterproductive.

Although the temperature to which the air is heated, about 180-190 degrees C, is comparable with the temperature of frying oil, air is far less efficient at transferring heat to food. While deep frying takes only five or six minutes, air frying can take three times as long. However, since no oil is being used, there is no worry about its carcinogenic breakdown products. Furthermore, hot air penetrates the food less effectively than hot oil, so the inside of the food doesn’t get as hot, which means significantly less acrylamide formation.

As far as crispiness goes, that is determined by the moisture content at the food’s surface. When food is placed in a deep fryer, the immediate bubbling seen is because of steam released from its surface. Hot air does not heat the surface quite as well, but still well enough to drive out moisture and produce crispiness. In the case of fries, this can be improved by first coating the potatoes with a thin layer of oil. If you really want to reduce oil-degradation products, the best choice is avocado oil because of its extremely high smoke point. I won’t say that my “air fries” are comparable with the best double-fried restaurant version, but they are very acceptable. And healthier.

Remember that the claim of french fries being as dangerous as smoking comes from someone who thinks that lamb testicles and raw liver are healthy, and cruciferous vegetables like broccoli, Brussels sprouts, chard and kale are “bulls–t.” These, Saladino says, should be avoided because “once chewed they produce sulforaphane, which is toxic to humans.”

Actually, sulforaphane has been shown to be an anti-carcinogen. So go for your broccoli and kale. If it is taste and crispiness you are after, put them in the air fryer. As far as Saladino’s TikTok videos go, after watching a bunch of them with their confusing message, I am led to conclude that this psychiatrist needs a psychiatrist.


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