Whether a carbohydrate-restricted diet is deficient in essential vitamins and minerals is another issue. As we also discussed (see Chapter 19), animal products contain all the amino acids, minerals, and vitamins essential for health, with the only point of controversy being vitamin C. And the evidence suggests that the vitamin C content of meat products is more than sufficient for health, as long as the diet is indeed carbohydrate-restricted, with none of the refined and easily digestible carbohydrates and sugars that would raise blood sugar and insulin levels and so increase our need to obtain vitamin C from the diet. Moreover, though it may indeed be uniquely beneficial to live on meat and only meat, as Vilhjalmur Stefannson argued in the 1920s, carbohydrate-restricted diets, as they have been prescribed ever since, do not restrict leafy green vegetables (what nutritionists in the first half of the twentieth century called 5 percent vegetables) but only starchy vegetables (e.g., potatoes), refined grains and sugars, and thus only those foods that are virtually without any essential nutrients unless they’re added back in the processing and so fortified, as is the case with white bread. A calorie-restricted diet that cuts all calories by a third, as John Yudkin noted, will also cut essential nutrients by a third. A diet that prohibits sugar, flour, potatoes, and beer, but allows eating to satiety meat, cheese, eggs, and green vegetables will still include the essential nutrients, whether or not it leads to a decrease in calories consumed.

My hope is that this book will change our views of the nature of a healthy diet, as the research for it changed my own; that future discussions of the nature of a healthy diet will begin with the quantity and quality of the carbohydrates contained, rather than the fat. As a challenge to the conventional wisdom on diet, obesity, and chronic disease, however, it presents a dilemma to public-health authorities; to nutritionists and physicians who believe that the advice they have been giving for the past few decades has been correct and based in sound science; and to all of us who simply want to eat healthy but have trouble accepting that everything we have come to believe could be as misguided as I have portrayed it. The resolution to this dilemma is to test the carbohydrate hypothesis rigorously, just as the fat-cholesterol hypothesis of heart disease should have been tested forty years ago.