A critique of low-carbohydrate diets.

Introduction

Obesity rates in the United States have risen steadily since 1980. As of 2014, one-third of Americans are obese. Obesity is associated with premature death from heart disease, stroke, type 2 diabetes, some cancers, and other conditions.
The SAD (Standard American Diet, what we commonly call a “Westernized diet”) threatens people’s health. Among the alternatives, the Atkins diet and other low-carb variations (such as the Paleo diet) achieved great commercial success following publications such as Dr. Atkins’ Diet Revolution (1972) and Dr. Atkins’ New Diet Revolution (1988).
Low-carb diets do produce weight loss while allowing people to eat bacon, steak, butter, and so on. The problem is that they seriously damage health. They are as unhealthy as the standard American diet, or worse.
The author (C. Campbell) has spent the past 40 years conducting experimental nutrition research at Virginia Tech and Cornell, working continually in both the lab and the field and keeping up with other researchers’ latest work.

The Low-Carb Appeal

Low-carb diets have many serious theoretical and clinical problems, yet remain popular. Why?
Over the past few decades, countless diets came into fashion but ultimately did little good, and the public began looking for alternatives. One commercially successful alternative in the 1980s was the Atkins diet, a form of low-carb eating.
Atkins’s greatest marketing achievement was coining “low-carb” and successfully persuading the public to avoid healthy plant foods. People could now freely eat steak, bacon, butter, lard, and so forth without worry. Starting a low-carb diet can also produce short-term weight loss.
The Atkins craze brought enormous benefits to the meat, dairy, and egg industries, which could now promote their products on the basis of “low-carb science.”

The Low-Carb Landscape

There are many low-carb diets, but the differences are mostly in marketing rather than substance. They share an encouragement of fear and loathing of carbohydrates and of obtaining most calories from protein and fat.

The Atkins diet

The earliest recorded case was William Banting, a British undertaker in the 1860s. He lost weight in the first few weeks, but the long-term results are unclear.
Dr. Atkins’ Diet Revolution (1972) and Dr. Atkins’ New Diet Revolution (1988) brought it widespread popularity. Atkins founded Atkins Nutritionals, achieving great commercial success selling Atkins-approved foods. The Atkins Foundation funds research on low-carb diets in relation to obesity, Alzheimer’s, testicular cancer, and other conditions.

Low-carb spin-offs

Following the Atkins diet’s commercial success, countless doctors and authors began writing books and developing products.
Well-known examples include Mary Dan and Michael Eaders’s Protein Power (1995), Barry Sears’s Enter the Zone (1995), Peter D’Adamo’s Eat Right 4 Your Type (1997), Loren Cordain’s The Paleo Diet (2002), Arthur Agatson’s South Beach Diet (2005), and Eric Westman’s The New Atkins for a New You (2010).
Each claims that their variation is more “correct” than the others: olive oil is better than butter and one should eat lean meat (South Beach Diet); water and supplements should compensate for low-carb diets’ problems (Protein Power); protein should provide 30% of calories and carbohydrates no more than about half (Enter the Zone, though the author considers less than half still low-carb); eat low-carb, high-fat, but emphasize whole foods (The Paleo Diet, though the author agrees whole foods matter, while low-carb, high-fat remains harmful).
These endless variations spread the mistaken impression that “low-carb” itself is healthy. Repeat even a bizarre claim often enough and it begins to sound increasingly true.

The Real Truth about Low-Carb Diets

Low-carb diets produce short-term weight loss, but because they focus on symptoms while leaving the causes of obesity untouched, they often cause other symptoms and sometimes even worsen obesity.
The first problem is that the effects are short-lived. Many observational studies clearly associate high-protein, high-fat diets with various obesity-related health problems.¹²³ Obesity is merely a symptom, like high blood pressure, blocked arteries, or angina, yet is problematically treated as a separate disease in its own right. Cancer also causes weight loss, but nobody wants that. The short-term weight loss caused by low-carb diets is not much different. Atkins himself died after suffering typical adverse effects of a high-protein, high-fat diet, including obesity and cardiac arrest.
Numerous studies establish that the Atkins diet causes constipation, headaches, bad breath, diarrhea, rashes, and so on. Vitamin supplements made no difference.⁴⁵ Research on the Atkins diet’s adverse effects is quite consistent and convincing. Even compared with the unhealthy standard American diet, the side effects are worse.

Gary Taubes and Low-Carb Sleight of Hand

Journalist Gary Taubes, author of Good Calories, Bad Calories (2007) and Why We Get Fat (2011), is the most prominent figure in the recent low-carb movement. His books have the merit of presenting detailed evidence for why low-carb diets are good, allowing the author, an expert, to criticize them specifically.

Where Taubes Gets It Right

He is right that calorie counting (dieting by tracking caloric intake) does not work.
Differences in how calories are digested, absorbed, and distributed in the body matter far more than caloric intake alone.
The claim that simply eating less and exercising more causes weight loss is not scientifically sound. The human body cannot sustain a low-calorie diet for long, and it is not a matter of willpower. Taubes explains this well.
Campbell himself has long criticized the practice of specifying recommended caloric intake as a particular number.

Where Taubes Gets It Wrong

Taubes labels calories from carbohydrates “bad calories,” arguing that sugar and other carbohydrates cause obesity in the US and other countries. Critiquing his position requires a precise understanding of carbohydrates. Many journalists, marketing agencies, and even doctors do not clearly understand their definition and meaning.

Carbohydrates

It is well known, for example, that extracting sucrose and consuming it in isolation is unhealthy. But low-carb advocates leap from “refined sugar is bad” to the mistaken conclusion that “all foods containing sugar are bad (and therefore carbohydrates are bad).” Taubes’s argument is more sophisticated than those of other low-carb advocates, but remains problematic.
Fruit, vegetables, and whole grains are all high in carbohydrates. The problem begins when different kinds are lumped together as “carbohydrates” without careful distinctions. Low-carbohydrate diets are almost inevitably meat-centered, making them high in fat (especially saturated fat). They also reduce intake of antioxidants, complex carbohydrates, vitamins, and minerals, while increasing protein intake excessively.

Number of calories vs. source of calories

If Taubes’s claim is that the source of calories matters more than their number, the author agrees in principle on that point. Plant-based and animal-based diets differ enormously in nutrient composition, producing differences far more important than the total number of calories alone.

Appendix: The Paleo Diet

(Omitted.)

The Low-Carb Fraud