Matt Fitzgerald's "Diet Cults: The Surprising Fallacy at the Core of Nutrition Fads and a Guide to Healthy Eating for the Rest of Us" delves into the pervasive world of nutrition fads, offering a critical perspective on the "one true way" mentality that dominates many popular diets. Fitzgerald, an endurance sports and nutrition writer, is not a doctor, but he understands science better than a lot of doctors who have written about diet and nutrition. The book examines the history and science behind various diet trends, advocating for a more rational and agnostic approach to eating.
The Core Argument: No Single "Best" Diet
Fitzgerald's central thesis is that there is no single "best" diet for all humans. This assertion stems from the observation that humans have evolved to be adaptable eaters, thriving on a wide variety of dietary intakes. As Fitzgerald notes, science has come as close as possible to confirming that there is no such thing as the healthiest diet. Adaptability is the hallmark of man as eater. If science had identified one optimum diet for human health, all the fads and arguments could have stopped by now.
The book challenges the notion that we should strictly adhere to a single dietary approach, such as the Paleo diet. Fitzgerald debunks the arguments for the Paleo Diet. There was no one paleolithic diet: our Stone Age ancestors ate a variety of diets determined by whatever they could get. Anyway, we couldn’t possibly eat like they did because their food sources are long gone. Today’s plants and animals have been drastically altered by selective breeding. The corn we eat is a far cry from the “natural” teosinte gathered by early humans. He points out that humans have continued to evolve since the Paleolithic era, developing adaptations like adult lactose tolerance. Moreover, technology has played a crucial role in improving our access to food, making a variety of eating patterns "natural" for humans. Science has not identified the healthiest way to eat.
The Fallacy of Moralizing Food Choices
One of Fitzgerald's key arguments is that humans have a natural propensity to make moral judgments about others’ food choices. This tendency, he suggests, likely originated as a practical way to encode knowledge about safe and unsafe foods, eventually becoming hardwired into human behavior due to its survival advantage for group cohesion. This moralizing of food choices is a central characteristic of "diet cults," which often present their dietary rules as morally superior to other ways of eating. Acknowledging that cult diets have existed since antiquity, he briefly examines Jewish eating laws and the food philosophies adhered to by followers of Confucius, then examines modern diets and concludes with his own "agnostic healthy eating game."
Diet Cults surveys the scientific literature on many trendy diets like raw food, Atkins, South Beach, Zone, Paleo, Vegan, Superfoods, gluten-free, as well as protein supplements and shows that almost all have no scientific merit. Fitzgerald notes that most popular diets advocate "one true way" of eating in order to attain maximum health while focusing on an "unnecessary avoidance of healthy foods."
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A Rational Approach: Agnostic Healthy Eating
Instead of advocating for a specific diet, Fitzgerald promotes an "agnostic, rational approach to eating habits, based on one's own habits, lifestyle, and genetics/body type." He suggests focusing on a balanced intake of whole foods, including vegetables, fruits, nuts, healthy meats and fish, whole grains, and dairy, while limiting refined grains, processed meats, sweets, and fried and processed foods.
His own eating guidelines are basic: eat mostly from a list of essential and recommended foods-vegetables, fruits, nuts, healthy meats and fish, whole grains, and dairy-and eat less refined grains, processed meats, sweets, and fried and processed foods. He recommends that we eat more of the categories higher on the list, and less as we go down the list. One could certainly argue with his list, and it hasn’t been tested to see if his plan will actually keep people healthier or make them live longer, but it seems to me that it is at least as reasonable as anyone else’s diet advice. Why not follow this plan while we are waiting for more conclusive scientific evidence? We don’t just eat for health, we also eat for enjoyment.
Fitzgerald, a certified nutritionist and athletics writer, concludes with his 'agnostic' diet recommendations that are very broad, but rooted in science, and tens of thousands of years of experience. In a nutshell, exercise regularly and primarily eat, in descending order, vegetables, fruits, nuts, unprocessed meat and seafood, dairy, whole grains, and, in lesser amounts, refined grains, processed meats, sweets, and, only in very small amounts, fried foods.
The Paradox of Choice and the Allure of Diet Cults
One reviewer highlights the importance of choice architecture in understanding the appeal of diet cults. The paradox of choice suggests that having too many options can be overwhelming and lead to decision fatigue. Diet cults, with their strict rules and limitations, can simplify the eating process, reducing the mental energy required for making food choices. As the reviewer notes, "It's an emotional drain to face limitless choices day in and day out. It's very taxing on will-power and decision-making."
This perspective suggests that the appeal of diet cults may not solely lie in their purported health benefits, but also in their ability to provide structure and eliminate the stress of making constant food decisions.
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Criticisms and Counterarguments
While "Diet Cults" offers a valuable critique of nutrition fads, it has also faced criticism. Some reviewers argue that the book lacks depth in its analysis of specific diets, relying on caricatures and pot-shots at the low-hanging fruit. For example, the book's discussion of veganism focuses heavily on raw vegans, neglecting the more moderate majority who also cook their food. Similarly, the portrayal of the Paleo diet emphasizes its extreme meat-centric form, overlooking the nuanced perspectives within the Paleo community that acknowledge individual differences and lifestyle factors.
One reviewer also points out that Fitzgerald's approach may not resonate with individuals who struggle with moderation and thrive on strict rules. For "abstainers," who find it easier to avoid certain foods altogether rather than consume them in moderation, diet cults can provide a helpful framework for managing their eating habits.
Another criticism is that Fitzgerald embraces food moralizing language like “good” foods and “bad” foods, although I suppose in his defense, maybe there’s air quotes that I can’t read in audiobook format, even while the purpose of the book is to argue against food rules.
Fitzgerald's Perspective on Athletes and Diet
Fitzgerald's background in endurance sports informs his perspective on diet and athletic performance. He observes that serious amateur endurance athletes are more likely to follow diet cults than their professional counterparts. He believes that the pros practice agnostic healthy eating because it is the simplest and safest way to eat for maximum performance. These folks don’t need the extra motivation to eat carefully that comes from submitting to some dietary doctrine and joining a community of likeminded eaters. They get all the motivation they need from the desire to win.
He also addresses the phenomenon of the "Sour Grapes Syndrome," where athletes who are not naturally competitive may adopt alternative training and dietary practices to gain a feeling of superiority over better athletes.
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