Hospitalized patients who are being fed nothing but glucose (sugar) intravenously for a long tim.
Babies who are being fed some bizarre substitute for breast milk Alcoholics who are getting too many of their calories from liquor.
In contrast, we never see protein deficiency among people who are eating enough food from any practical plant-based diet to get enough calories.
Theoretically, you could get a protein deficiency from eating nothing but apples, but nobody would eat a diet like that for any length of time.
No wonder vegetarians and vegans get annoyed when someone asks, “But where do you get your protein?”
After all, where do gorillas get their protein?
From the nutrition textbooks I edited, I learned something even more disturbing about calcium.
As a woman in the United States, I have been bombarded with advice to eat huge amounts of calcium. The only practical way to get that much calcium is to eat dairy products or take calcium supplements.
Yet according to the books I edited, the bone-thinning disease osteoporosis is most common where people consume the most dairy products.
A high-protein, high-calcium diet increases your risk of getting osteoporosis. In contrast, low calcium intakes, per se, did not seem to be a problem.
Female gorillas manage to get enough calcium from their plant-based diet to grow a big, strong skeleton. Also, female rhesus monkeys go through menopause, but they do not get osteoporosis after menopause.
The lessons that I learned from nutrition textbooks were wildly different from the lessons that I was taught in school and from the messages that were being spread by the commercial media.
Naïvely, I figured that the scientific truth would eventually trickle down to consumers or at least to medical doctors.
But over the following 25 years, the state of nutritional knowledge among the general public and even the medical profession seemed to be getting worse, not better.
People seemed to be learning a larger number of “facts” that were actually false. The Internet seemed to be a mixed blessing. It gave me access to an enormous amount of scientific information, often for free. Unfortunately, it was also being used to spread total nonsense.
Many Americans have been led to believe that the common forms of heart disease and diabetes are genetic. But if that were true, heart disease would be just as uncommon among Japanese immigrants in the United States as it is among Japanese in Japan. I
n reality, people of Japanese ancestry start getting heart disease like Americans when they start eating like Americans.
If type 2 diabetes were really genetic, then type 2 diabetes would be no more common today than it was 50 years ago.
The fact that the incidence of type 2 diabetes has been rising sharply tells you that type 2 diabetes should not be considered a genetic disease. (As I explain in my book Thin Diabetes, Fat Diabetes, there are some truly genetic forms of diabetes, but they are rare.)
If you look at old family photograph albums or at crowd scenes from historical documentaries, you will probably be stunned by how thin most people were 50 years ago.
Since then, Americans have become fatter and fatter. This epidemic of obesity is even spreading to Asia and Africa, as Asians and Africans start to eat more like Americans.
Because of the low-carb diet craze, most Americans believe that obesity is due to diets that are high in carbohydrates (starches and sugars). However, the Asians and Africans who are continuing to eat a traditional high-carbohydrate diet remain slim.
The promoters of low-carbohydrate diets have been spreading the idea that heart disease and type 2 diabetes result from eating starchy foods.
In reality, heart disease and type 2 diabetes are rare in societies that eat a heavily starch-based diet. They can even be reversed by eating a heavily starch-based diet.
Nowadays, many of the people I meet are convinced that they need to avoid carbohydrates (starches and sugars).
They are convinced that they would be less likely to get heart disease if they ate more fish or added some sort of magical fat supplement to their diet. Most of the middle-aged and elderly women I know take calcium supplements, and some of the vegetarians still worry about protein deficiency.
In other words, most of the people I talk to are not just uninformed about nutrition—they have been wildly misinformed. My goal in writing this book is to help people find the truth amid all that nonsense.
It is hardly surprising that so many people are misinformed about diet. The problem is serious even in the medical profession.
Every few years, some expert panel delivers a disturbing report, warning us that medical students are not learning enough about nutrition and dietetics in medical school.1-5 Unfortunately, the problem never seems to get solved. Years go by, and eventually another alarming report gets issued.
Over the years, I have met a few people who studied nutrition or epidemiology in college or graduate school. Nearly everyone else gets their information about diet and nutrition from magazines, radio programs, books, and Web sites.
Unfortunately, the dietary advice that you get from the commercial media is usually just an attempt to get you to buy something, not an attempt to help you improve your health.
The people who get airtime on the radio and the people who write books and produce videos and Web sites for a consumer audience seldom have any formal training in nutrition and dietetics.
As a result, they tend to spread dangerous nonsense, rather than helping people learn the truth.
A shockingly high percentage of the bestselling books on nutrition are full of total nonsense. The companies that publish these bestsellers are not scientific or educational institutions. Nor are they public health agencies.
Instead, they are businesses that make money by publishing books that are likely to sell, even if those books are not good for public health.
The books that show up on the bestseller lists have not gone through the kind of scientific review (“peer review”) that is routine in scientific publishing. In contrast, I send everything I write to scientific experts for review.
All of the populations of slim, healthy people throughout history have obtained the bulk of their calories from starchy staples, such as rice, wheat, corn, or potatoes.
The populations that eat a starchy diet have low rates of obesity and other chronic degenerative diseases. Unrefined starchy foods, along with vegetables and fruit, truly are health foods.
Many people are shocked to hear that they would be better off eating conventionally grown grains and produce, including plenty of “carbs,” than eating organic grassfed beef and dairy products. Of course, the ideal would be to eat organic grains and produce.
Like most people in the United States, I was taught that children need to eat foods from the meat group (meat, eggs, and fish) and the dairy group (milk, cheese, yogurt, and butter) in order to grow up big and strong.
I was encouraged to believe that human adults need to continue eating meat and dairy foods to maintain good health and athletic performance.
So when I started reading nutrition textbooks, I was relieved to discover that vegetarians (people who don’t eat meat) and even vegans (people who refuse to consume any animal-source products) are not at risk for a deficiency of protein, calcium, or iron.
Rather, the scientific studies showed that eating even small amounts of foods that come from animals poses an unnecessary risk to human health.
Many people decide to become vegetarian or vegan because of how they feel about animals. For them, the
question about whether to eat meat or wear fur or leather is a moral question.
However, I did not write this book to talk about moral questions. In this book, I deal with the scientific questions about how your food choices are likely to affect your health. If a plant-based diet posed health risks to human beings, I would explain those risks in detail and would describe how to minimize that risk.
Fortunately, the plantbased diet that many people have been promoting because of concerns about animal welfare or the environment also happens to be the diet that is best for human health.
My point is that you do not need to sacrifice your health in order to protect animals and save the environment.
On the other hand, if you switch to a plant-based diet to improve your own health, you will also spare the lives of animals and cause less damage to the environment.
Although the health-optimizing diet for a human being consists of plant-based foods, I try to avoid calling it a vegetarian or vegan diet. Many people who call themselves vegetarian eat a lot of dairy foods and eggs, or even a lot of fish. (A fish is an animal, not a vegetable!)
Also, many vegetarians and even many vegans are eating far too much fat (especially too much omega-6 fat in the form of seeds and vegetable oils) and drinking too much alcohol. Bourbon and potato chips are vegan, but they aren’t health food!
The rules of thumb that I listed above (e.g., eat plants, not animals) are general rules that apply to the average person.
However, there are a few people who need custom-tailored advice from a trained professional. For example, people with some hereditary metabolic diseases, such as phenylketonuria, need special diets.
People with fructose malabsorption may get diarrhea if they eat too many apples or pears. People with celiac disease need to avoid wheat, rye, and barley. If you need a special diet for health reasons, you should talk to a registered dietitian.
Note that even a sudden change to a healthy diet can cause problems. If you have any serious health problem or are taking prescription medications, you need to talk to your doctor, nurse practitioner, or physician assistant before you make a major change in diet.
A sudden switch to a healthy diet can cause rapid improvements in circulation and insulin sensitivity. As a result, people may need to stop taking some of their blood pressure medication. Diabetics may also need adjustments in their diabetes medications.
If you correct your diet without allowing your doctor to adjust your prescription medications, you could pass out from low blood pressure. You could even end up in the hospital or dead from low blood sugar!