1774. The Myth of High-Protein Diets

By Dean Ornish, The New York Times, March 23, 2015

MANY people have been making the case that Americans have grown fat because they eat too much starch and sugar, and not enough meat, fat and eggs. Recently, the Dietary Guidelines Advisory Committee lifted recommendations that consumption of dietary cholesterol should be restricted, citing research that dietary cholesterol does not have a major effect on blood cholesterol levels. The predictable headlines followed: “Back to Eggs and Bacon?”

But, alas, bacon and egg yolks are not health foods.

Although people have been told for decades to eat less meat and fat, Americans actually consumed 67 percent more added fat, 39 percent more sugar, and 41 percent more meat in 2000 than they had in 1950 and 24.5 percent more calories than they had in 1970, according to the Agriculture Department. Not surprisingly, we are fatter and unhealthier.

The debate is not as simple as low-fat versus low-carb. Research shows that animal protein may significantly increase the risk of premature mortality from all causes, among them cardiovascular disease, cancer and Type 2 diabetes. Heavy consumption of saturated fat and trans fats may double the risk of developing Alzheimer’s disease.

A study published last March found a 75 percent increase in premature deaths from all causes, and a 400 percent increase in deaths from cancer and Type 2 diabetes, among heavy consumers of animal protein under the age of 65 — those who got 20 percent or more of their calories from animal protein.

Low-carb, high-animal-protein diets promote heart disease via mechanisms other than just their effects on cholesterol levels. Arterial blockages may be caused by animal-protein-induced elevations in free fatty acids and insulin levels and decreased production of endothelial progenitor cells (which help keep arteries clean). Egg yolks and red meat appear to significantly increase the risk of coronary heart disease and cancer due to increased production of trimethylamine N-oxide, or TMAO, a metabolite of meat and egg yolks linked to the clogging of arteries. (Egg whites have neither cholesterol nor TMAO.)

Animal protein increases IGF-1, an insulin-like growth hormone, and chronic inflammation, an underlying factor in many chronic diseases. Also, red meat is high in Neu5Gc, a tumor-forming sugar that is linked to chronic inflammation and an increased risk of cancer. A plant-based diet may prolong life by blocking the mTOR protein, which is linked to aging. When fat calories were carefully controlled, patients lost 67 percent more body fat than when carbohydrates were controlled. An optimal diet for preventing disease is a whole-foods, plant-based diet that is naturally low in animal protein, harmful fats and refined carbohydrates. What that means in practice is little or no red meat; mostly vegetables, fruits, whole grains, legumes and soy products in their natural forms; very few simple and refined carbohydrates such as sugar and white flour; and sufficient “good fats” such as fish oil or flax oil, seeds and nuts. A healthful diet should be low in “bad fats,” meaning trans fats, saturated fats and hydrogenated fats. Finally, we need more quality and less quantity.

My colleagues and I at the nonprofit Preventive Medicine Research Institute and the University of California, San Francisco, have conducted clinical research proving the many benefits of a whole-foods, plant-based diet on reversing chronic diseases, not just on reducing risk factors such as cholesterol. Our interventions also included stress management techniques, moderate exercise like walking and social support.

We showed in randomized, controlled trials that these diet and lifestyle changes can reverse the progression of even severe coronary heart disease. Episodes of chest pain decreased by 91 percent after only a few weeks. After five years there were 2.5 times fewer cardiac events. Blood flow to the heart improved by over 300 percent.

Other physicians, including Dr. Kim A. Williams, the president of the American College of Cardiology, are also finding that these diet and lifestyle changes can reduce the need for a lifetime of medications and transform people’s lives. These changes may also slow, stop or even reverse the progression of early-stage prostate cancer, judging from results in a randomized controlled trial.

These changes may also alter your genes, turning on genes that keep you healthy, and turning off genes that promote disease. They may even lengthen telomeres, the ends of our chromosomes that control aging.

The more people adhered to these recommendations (including reducing the amount of fat and cholesterol they consumed), the more improvement we measured — at any age. But for reversing disease, a whole-foods, plant-based diet seems to be necessary.

In addition, what’s good for you is good for our planet. Livestock production causes more disruption of the climate than all forms of transportation combined. And because it takes as much as 10 times more grain to produce the same amount of calories through livestock as through direct grain consumption, eating a plant-based diet could free up resources for the hungry.

What you gain is so much more than what you give up.

Dean Ornish is a clinical professor of medicine at the University of California, San Francisco and the founder of the Preventive Medicine Research Institute.

1588. Food: How Meat Advocates Skewer Science

By The Physicians Committee for Responsible Medicine, Good Medicine, Autumn 2014

In 1974, a new book titled We Never Went to the Moon: America’s Thirty Billion Dollar Swindle alleged that NASA faked the lunar landing. In 2001, the Fox network broadcasted a documentary on the subject, and a follow-up survey showed that as many as one in five Americans doubted that Neil Armstrong’s boots had ever touched the moon’s surface.

Fast-forward to June 23, 2014. Time magazine’s cover proclaimed in large type “Eat Butter” and featured a big artistic swirl of the stuff. Several other publications—the New York Times, the Wall Street Journal, the New Scientist, and others—ran similar stories. The experts have been wrong all this time, the articles exclaimed. Fat isn’t unhealthy after all. Steak and pork chops won’t hurt you. Go ahead, dig in!

Of course, meat and dairy products are strongly linked to all manner of health problems, from heart disease to cancer, diabetes, obesity, and hypertension. So what is behind the contrarian stories?

Eskimos and Maasai

Some of the articles were based on a new book called The Big Fat Surprise: Why Butter, Meat, and Cheese Belong in a Healthy Diet. Its author, Nina Teicholz, aimed to rehabilitate meat’s image, starting with Eskimo and Inuit populations of the far north. They have almost no heart disease, she held, despite a diet heavy on fish and blubber. Was she right or wrong? 

Wrong. A study from the University of Ottawa Heart Institute published in the Canadian Journal of Cardiology showed that cardiovascular disease has been at least as frequent among northern native populations as for others.1 Strokes have been particularly common, and life expectancy overall was found to be about a decade shorter. Heart disease seemed rare among northern native populations mainly because reporting of medical problems has been spotty.

Teicholz then invoked the Maasai, an African population who are supposedly free of heart disease, despite a diet of meat, milk, and blood. Right or wrong? 

Wrong. Researcher George V. Mann wrote in 1978, “We have collected hearts and aortae from 50 authenticated Maasai men who died of trauma and we found extensive atherosclerosis.”2

Okay, so the Maasai’s arteries are clogged with atherosclerotic plaques. But they don’t have heart attacks, Teicholz maintained; so meat and milk must be safe. Right or wrong? 

Wrong. Plaques that form in arteries can rupture, sparking the formation of a clot that blocks blood flow like a cork in an artery, causing a heart attack. Teicholz’s notion was that the Maasai have plaques, but the plaques somehow never rupture, like time bombs that never explode. This is highly unlikely. A better explanation for the lack of reported heart attacks among the Maasai comes from their tragically short life expectancy. If life is cut short in one’s 40s by an accident or an infection, plaques have not had enough time to produce a heart attack. Moreover, in a rural population with limited medical care and poor medical records, heart attacks may not be recognized or reported.

Ancel Keys and the Seven Countries Study 

Teicholz and other fat-backers zeroed in especially on Ancel Keys, the University of Minnesota researcher who identified the dangers of fatty foods in the 1950s. Looking at six countries with reliable dietary and medical records, Keys found a clear association between fat intake and heart disease deaths.3

But as Teicholz tells it, the rug was pulled out from under Ancel Keys by University of California at Berkeley statistician Jacob Yerushalmy.4 If Keys had zeroed in on more countries than just six, Yerushalmy held, the relationship between saturated fat and heart disease would have been weakened. In Teicholz’s words, it “nearly disappeared.” Right or wrong? 

Wrong. Including additional countries, as Yerushalmy suggested, did muddy the correlation between fat and heart disease deaths, because many of these countries had poor data on diet or medical care at that time. Even so, the correlation between fat and heart deaths remained high, and the correlation between animal protein and heart deaths was even higher.

Meta-analysis 

What really grabbed the headlines, however, was a meta-analysis published in early 2014 by the Annals of Internal Medicine.5 The meta-analysis combined 72 smaller studies, finding no overall effect of saturated fat on heart risks. According to the fat lobby, that proved that “bad” fat isn’t bad for your heart after all. Right or wrong?

Wrong. The Annals meta-analysis combined data from many studies. Some were designed to accurately show the dangerous effects of saturated fat. The designs of other studies did not make the hazards of saturated fat readily apparent. The net result was that the two types of studies canceled each other out, showing no risks. For example, take these two studies the Annals meta-analysis included:

The Oxford Vegetarian Study6 included 11,000 people whose diets ranged from vegan to ovolactovegetarian to nonvegetarian, with saturated fat intake ranging from a low of 6 percent of calories to more than 13 percent of calories. The study found that the fattiest diets tripled the risk of dying of heart disease, compared with diets that had very little saturated fat.

But in a Swedish study, no groups were on lower-fat diets. All of the study groups averaged more than 13 percent of their calories from saturated fat. Not surprisingly, the study could not identify any effect of avoiding saturated fat, because no groups in the study had a low fat intake.

Is Meat Safe or Not? 

Of course, no one orders saturated fat at a restaurant or puts it on a shopping list. This fat is hidden in meat, dairy products, and other foods. And here, the evidence is crystal clear. Meat-eaters are heavier than people who avoid meat. They have higher blood pressure, higher risk of diabetes, cancer, heart disease, and many other problems. And in carefully controlled studies, when people take meat out of their diets, they lose weight, and cholesterol, diabetes, and heart disease all improve. So while researchers debate the statistics on saturated fat, it pays to remember that getting away from meat is a healthy choice. 

So how could the media have been duped? As John McDougall, M.D., said, people are always looking for good news about bad habits.

1. Fodor GJ, Helis E, Yazdekhasti N, Vohnout B. “Fishing” for the origins of the “Eskimos and heart disease” story: facts or wishful thinking? Can J Cardiol. 2014;30:864-868.
2. Mann GV. The Masai, milk, and the yogurt factor: an alternative explanation. Atherosclerosis. 1978;29:265.
3. Keys A. Atherosclerosis: a problem in newer public health. J Mt Sinai Hosp NY. 1953;20:118-139.
4. Yerushalmy J, Hilleboe HE. Fat in the diet and mortality from heart disease: a methodologic note. NY State J Med. 1957;57:2343-2354.
5. Chowdhury R, Warnakula S, Kunutsor S, et al. Association of dietary, circulating, and supplement fatty acids with coronary risk: a systematic review and meta-analysis. Ann Intern Med. 2014;160:398-406.
6. Appleby PN, Thorogood M, Mann JI, Key TJA. The Oxford Vegetarian Study: an overview. Am J Clin Nutr. 1999;70:525S-531S.
7. Wallstrom P, Sonestedt E, Hlebowicz J, et al. Dietary fiber and saturated fat intake associations with cardiovascular disease differ by sex in the Malmo Diet and Cancer Cohort: a prospective study. PLoS One. 2012;7:e31637.