As I mentioned in my recent post introducing Mark’s Daily Apple, I have become more interested in understanding diet, nutrition, and health. Sadly, this doesn’t come without challenges, and in this post, I’d like to discuss some of the current controversies that make it difficult for me to decide what to eat in order to maintain a healthy life.

First, let me provide some background. During elementary and middle school, I learned about the United States Department of Agriculture’s infamous food pyramid. Of course, like most Americans, I didn’t adhere to it exactly, but I at least kept it in mind, so it did impact the way I ate for most of my life.

After reading Fast Food Nation, I also avoided most forms of fast food starting in high school. On the surface, this diet approach seems to be excellent — just follow the food pyramid and avoid McDonald’s. Unfortunately, up until now, I had been unaware of the vast amount of misinformation, politics, and shoddy science of food that plague the country and are likely correlated with the shocking prevalence of obesity, heart disease, diabetes, and other chronic illnesses.

First, let’s go over a few hopefully non-controversial facts:

  1. In 2012, 34.9% of U.S. adults and 16.9% of U.S. youth were obese; in the early 1960s, obesity among U.S. adults was estimated at 13.4%. If we expand the pool of people to include those who are overweight (i.e., BMI of at least 25) then the percentage of overweight adults from 1962 to 2010 rose from less than 50% to more than 70%.
  2. Heart disease is now the leading cause of death for Americans, with the latest estimates pegging it in causing one out of every four deaths.
  3. In 2012, about 29.1 million Americans had diabetes, and almost two million new cases are diagnosed annually.
  4. The global pharmaceutical industry is expected to rake in $1,200 billion by 2016, of which the U.S. has the largest share.
  5. The estimated medicate costs of obesity in the U.S. is currently almost $150 billion.

I could go on and on, but I think the point is clear: the United States has a health crisis, and I’m pretty confident that we don’t need too many drugs to help us out. The human species, after all, cannot evolve so quickly over two generations to produce a much heavier population.

Fortunately, the rise in obesity and chronic illnesses has not gone unnoticed. The American Heart Association has established the following dietary recommendations to reduce the risk of heart disease:

  1. Choose lean meats and poultry without skin, saturated fat, and trans fat
  2. Eat fish at least twice a week
  3. Select low-fat or no-fat dairy products
  4. Cut back on food with partially hydrogenated vegetable oils (i.e., trans fat)
  5. Reduce consumption of saturated fat to lower cholesterol
  6. Avoid sugary beverages
  7. Prepare food without using too much salt to lower blood pressure
  8. Drink alcohol in moderation
  9. Pay attention to portion sizes

This is what I will refer to as conventional wisdom, and nowadays, the public perception is that diets high in fat result in weight gain, which subsequently leads to a whole host of other problems. Meanwhile, a healthy diet is low-fat, low-cholesterol, low-sodium, and plant-based (including grains). An example is the Ornish diet, which claims to reduce the incidence of heart disease by requiring that no more than 10 percent of calories come from fat. It was created by Dr. Dean Ornish, Clinical Professor of Medicine at the University of California, San Francisco, whose books and nutrition program have won him widespread acclaim. After all, not everyone can say that they serve as a health advisor to Bill Clinton.

Unfortunately, the past few decades has suggested a paradox. Indeed, spurred by the government war on fat, Americans have been consuming less fat in recent decades, as shown by that 1998 paper (by the way, please let me know if you find a more recent reference). In 1965, the estimated daily intake of fat for American men and women was 139 grams and 83 grams, respectively, and in 1995, those figures were 101 grams and 65 grams, respectively. Furthermore, there is a consistent decrease in the percent of daily calories from fat, from 45% in 1965 to 34% in 1995. The caveat here is that the total caloric consumption of Americans has also increased, which might mitigate the “positive” effect of lowering fat, but if so, shouldn’t the rise in chronic illnesses be blamed to whatever else we’re eating to get those calories?

In addition, the percentage of American adult smokers dropped from 42.4% in 1965 to 19.0% in 2011. So something must be counteracting this beneficial effect because all signs point to an increase in chronic illnesses. Also, while Americans are living longer, that doesn’t mean our final years are that great. Our extended lifespan is largely due to better medical treatment that wasn’t available in earlier eras, and not due to an improved diet.

Good Calories, Bad Calories

In Good Calories, Bad Calories, Gary Taubes argues that United States government and health organizations have given us dietary advice that contradict the science. Taubes starts by explaining some of the earliest observational studies of the health of native populations before and after dietary changes (i.e., “Westernization” of diet). He then moves his way towards the mid-1900s, which coincided with the prominence of Ancel Keys and a new era of dietary advice that encouraged consumption of carbohydrates (including “white” bread/rice/cereal/pasta) and demonized saturated fat as the cause of heart disease. According to Taubes, the science showed, and continues to do so today, that saturated fat has little correlation with heart disease while the link between refined carbohydrates, sugars, and chronic illnesses is much stronger.

Good Calories, Bad Calories is ultimately a brutal attack on conventional wisdom. (By the way, I would like to point out that there’s a fair amount of support for following a vegan diet to obtain optimal health, so these people are also technically challenging conventional wisdom, but for the purposes of this post, as you have probably determined, I am mainly going to discuss the low-carb paradigm.)

In addition to what I mentioned earlier about the AHA and the Dean Ornish diet, conventional wisdom also proclaims that people can obtain a healthy body weight by “eating less and exercising more.” But this is problematic, Taubes says, because exercising more tends to cause an increase in appetite. For instance, athletes are known to require more calories than the average sedentary person.

When considering the totality of conventional wisdom, here is one of my attempts to sum up Taubes’ advice in one sentence:

“To be healthy, be sure to eat the right kind of calories from unprocessed meats and vegetables and avoid refined carbohydrates and sugars (including whole grains and processed foods); good exercise, while beneficial, cannot make up for a terrible diet.”

What is my opinion on Good Calories, Bad Calories? I have mixed feelings. Taubes is right on diet in many respects, but I’m not sure if people should be switching to a meat-heavy diet, which is what Taubes appears to advocate (but he never explicitly says so). Before reading the book, I was already aware of how saturated fat and cholesterol probably aren’t as bad as we (by that, I mean “conventional wisdom thinkers”) think they are. I had read Chris Kresser, Mark Sisson, and Zoe Harcombe, among others, give their take on cholesterol and similar topics, but I still tried to read the book with an open mind and a healthy level of skepticism, as none of the three people I just mentioned are true medical researchers. Good Calories, Bad Calories is definitely on the dense side in terms of writing style, but a lot of his analysis makes sense, and I have to say that the history of nutrition science and advice is interesting. My conclusion is that I think that anyone who has serious interest in diet and health should take a look at this book. It’s dense and has sixty six (!) pages of references, which is necessary to ensure that, as Taubes would later say, “to never take what I say on trust alone.” In fact, Taubes is not a nutritionist, but a science journalist; he got a Bachelor’s degree in physics from Harvard University.

Please don’t interpret the preceding paragraph as a full-on support of Taubes. I knew after reading this book that I needed to see if there was any legitimate criticism that would make me second-guess his advice. And by far, by far, the best review I’ve found of Good Calories, Bad Calories is a series of blog posts by a nutrition guy named Seth. And … wow, if Taubes relentlessly criticized the government in his book, Seth takes that kind of criticism, multiples it by ten, and levels it back at Taubes! It’s definitely a good read just to make sure that you don’t get too trapped into the whole “low-carb” ideology.

Just to be clear, Taubes doesn’t disagree with all of conventional wisdom. No one is out there advocating that Coke and Pepsi belong in a healthy diet, and that we should eschew non-starchy vegetables. The controversy is on the role that saturated fat, cholesterol, grains, and meat play in a healthy diet. Taubes never gives specific dietary advice, but his reader-friendly version (Why We Get Fat) does give a diet plan, which allows mainly unprocessed meats and non-starchy vegetables. He also has a cholesterol blog post, where he boasts about his cholesterol numbers while describing his diet as “eggs, sausage, cheese, cheeseburgers (no bun), steaks … high in fat, low in carbohydrates.”

Now, I know that the obvious reaction is to dismiss Taubes as a outsider to nutrition who doesn’t know what he’s talking about. But let’s start looking at some other sources that clearly have credibility.

Here’s one: the American Diabetes Association (ADA). They have to have some dietary advice, right? Good Calories, Bad Calories goes at length to explain how refined carbohydrates and sugars can induce diabetes, so it will be interesting to see how Taubes’ ideas match up.

I went to their page on Grains and Starchy Vegetables, where I saw this:

There is no end in sight to the debate as to whether grains help you lose weight, or if they promote weight gain. Even more importantly, do they help or hinder blood glucose management?

One thing is for sure. If you are going to eat grain foods, pick the ones that are the most nutritious. Choose whole grains. Whole grains are rich in vitamins, minerals, phytochemicals and fiber.

Reading labels is essential for this food group to make sure you are making the best choices.

Every time you choose to eat a starchy food, make it count! Leave the processed white flour-based products, especially the ones with added sugar, on the shelves or use them only for special occasion treats.

With that, the ADA just made me worried. I have to be honest: if I had diabetes, how could I feel comfortable eating grains — even whole grains — if the ADA can’t take a definitive stance on this, and suggests the possibility of “promote weight gain” and “hinder blood glucose management” as side effects? They do gently suggest eating whole grains on other parts of their website … but why not here, on the page that actually discusses it?

Here’s a second source that should be credible: the Harvard School of Public Health Nutrition Guidelines. But unfortunately, I remain worried. Here’s what they have to say in their 2011 article:

Nearly two decades ago, the U.S. Department of Agriculture (USDA) created a powerful icon: the Food Guide Pyramid. This simple illustration conveyed in a flash what the USDA said were the elements of a healthy diet. The Pyramid was taught in schools, appeared in countless media articles and brochures, and was plastered on cereal boxes and food labels.

Tragically, the information embodied in this pyramid didn’t point the way to healthy eating. Why not? Its blueprint was based on shaky scientific evidence, and it barely changed over the years to reflect major advances in our understanding of the connection between diet and health.

Wait … “shaky scientific evidence?” That’s not what I want to hear! Could Taubes be onto something after all? They continue their description by criticizing how current guidelines don’t penalize white/refined grains enough (so this is a point for Taubes), don’t penalize red meat enough (so this is a point against Taubes) and recommend too much dairy (I don’t think Taubes talks too much about dairy, so I’ll consider this a wash). The Harvard pyramid and associated article is an interesting read, and makes me feel much better that I base my diet on vegetables and have never been a huge milk drinker despite how doctors and others told me to drink more milk when I was young (thank goodness I didn’t!).

So, from the Harvard guidelines, whole grains play a foundational role in a healthy diet, but refined grains are almost as bad as you can get in terms of food! Is this the right answer? Are whole grains really that much better? Well, I obviously don’t know the answer. I’ll have to be honest, I’m leaning towards supporting the Harvard pyramid, but again, there are many experts who would disagree; Dean Ornish, for instance, would oppose the allowance of egg yolks, which he classifies as among the worst foods to eat. And he advised Bill Clinton on his diet! But here’s something else that’s interesting … Bill Clinton also has a second dietician, Mark Hyman, who has encouraged Clinton to eat more fat! Thus, Clinton has two major medical minds giving him polarizing advice on the amount of fat (and eggs) to eat. As the article suggests, if Clinton can’t come to a consensus, what hope is there for the rest of us? The best-case scenario, of course, is if both diets are great. And they obviously are, when the baseline is a diet of McDonald’s and Pizza Hut. But how do they compare against each other? That’s the major question.

Going Against Conventional Wisdom

Given that there are some aspects of diet that don’t seem to have a consensus, I thought I’d just try and see what people are saying. My goal is to synthesize some of the well-known books that advocate at least one of the prevalent themes from Good Calories, Bad Calories, which among them are “fats are fine, refined carbohydrates and sugars far worse,” “low-carb living,” and “governmental impact on nutritional science.” Most or all of these books will substantially challenge conventional wisdom.

This in no way means I support these arguments — the purpose of seeing all these books is that it raises doubt about conventional wisdom. While it does sound disconcerting, I ultimately think it’s best if we know all this information, because then we can do our own independent research and can make informed decisions. And again, a healthy level of skepticism (but not too much) is needed as part of science, and this is what makes nutrition science so great — it’s generally accessible to people who are outsiders, at least way more than computer science.

I tried to ignore books that were diet or recipe-related (there are a lot of “Paleo Recipe” books out there) in favor of ones that take at least a scientific approach to nutrition by citing studies and forming logical arguments. The one exception might be the Atkins diet book, but that was the one that really started the whole low-carb movement, and I think Atkins (who was a cardiologist) did have some science to back him up beyond his trials on himself and his co-workers.

The books are ordered by their original publication date, though many have been updated at least once. A number of them, such as Taubes’ books, are New York Times or National bestsellers. You’ll also notice that the majority of them are from the recent decade. This is not surprising; Taubes explicitly mentions at the end of Good Calories, Bad Calories, that the Internet was the main reason why he was able to find all the sources he did.

So, here’s a list of books I found:

  1. Pure, White, and Deadly: How Sugar is Killing Us, and What We Can Do to Stop It, by John Yudkin. (1972, updated in 1986 and 2012)
  2. Dr. Atkins’ Diet Revolution, by Robert Atkins. (1972, updated 2009)
  3. Protein Power, by Michael and Mary Dan Eades. (1997)
  4. The Great Cholesterol Con, by Anthony Colop. (2006)
  5. Good Calories, Bad Calories: Fats, Carbs, and the Controversial Science of Diet and Health, by Gary Taubes. (2007)
  6. The Great Cholesterol Con: The Truth About What Really Causes Heart Disease and How to Avoid It, by Malcolm Kendrick. (2008)
  7. The Primal Blueprint: Reprogram Your Genes for Effortless Weight Loss, Vibrant Health, and Boundless Energy, by Mark Sisson. (2009, updated 2013)
  8. The Paleo Solution: The Original Human Diet, by Robb Wolf. (2010)
  9. Wheat Belly: Lose the Wheat, Lose the Weight, and Find Your Path Back to Health, by William Davis. (2011, updated 2014)
  10. Why We Get Fat: And What to Do About It, by Gary Taubes. (2011)
  11. The Art and Science of Low Carbohydrate Living, by Stephen Pinney and Jeff Volek. (2011)
  12. The Art and Science of Low Carbohydrate Performance, by Stephen Pinney and Jeff Volek. (2011)
  13. The Great Cholesterol Myth: Why Lowering Your Cholesterol Won’t Prevent Heart Disease — and the Statin-Free Plan That Will, by Johnny Bowden and Stephen Sinatra (2012)
  14. Fat Chance: Beating the Odds Against Sugar, Processed Foods, Obseity, and Disease, by Robert Lustig. (2012)
  15. Grain Brain: The Surprising Truth about Wheat, Carbs, and Sugar — Your Brain’s Silent Killers, by David Perlmutter. (2013)
  16. Death by Food Pyramid: How Shoddy Science, Sketchy Politics, and Shady Special Interests Have Ruined Our Health, by Denise Minger. (2013)
  17. Eat the Yolks, by Liz Wolfe. (2014)
  18. The Big Fat Surprise: Why Butter, Meat, and Cheese Belong in a Healthy Diet, by Nina Teicholz. (2014)
  19. Keto Clarity: Your Definitive Guide to the Benefits of a Low-Carb, High-Fat Diet, by Eric Westman and Jimmy Moore (coming soon!)

Wow. That’s a lot of books, and honestly, it didn’t take me a long time to find these. And as you can see by looking at the authors, we’re seeing more and more people with medical degrees support the general idea of following a low-carb diet.

One major problem with these books, and indeed, this entire low-carb argument, is the “cherry-picking” involved, when authors look at research studies and selectively choose the ones that fit their hypothesis while ignoring other studies that don’t. Then again, who’s to say that the same isn’t happening for people who advocate eating lots of starch? And even books that take a scientific-based approach to suggesting a high-starch or low-meat diet, such as The China Study, have their own critics. I haven’t read The China Study, but it’s on my agenda.

By the way, I should mention that the author of The China Study, T. Colin Campbell, is Professor Emeritus of Nutritional Biochemistry at Cornell University. He advocates a low-fat, vegan diet, but that’s not what the Harvard food pyramid implies. In fact, even Dean Ornish doesn’t advocate a vegan diet. Look at his spectrum of food choices again, and you’ll see egg whites and fat free milk in his “Group 1: Most Healthful” foods. (And, uh … beer is also in the “Most Healthful” category. That’s interesting … I don’t know how that ended up on there.)

If there is this much out there that seems to contradict what the American Heart Association and conventional wisdom dictate, then doesn’t this at least raise some doubt? (Don’t forget to also consider books that suggest a vegan diet.)

I guess my point is that if we are getting advice about nutrition from the government, it should be established beyond a reasonable doubt. Otherwise, I would rather see phrases like “we are still considering all evidence and are unsure about this….”

Dr. Yudkin and Sugar

Unfortunately, one of the biggest takeaways that I got from Good Calories, Bad Calories and my own brief research is that, after fat became demonized, people and industry looked for alternatives, and they found that in sugar. In fact, Taubes said that prominent nutritionists and professors at elite universities were recommending sugar, and that it was a safe alternative to fat, even as late as the 1980s. But Dr. John Yudkin disagreed, and published Pure, White, and Deadly: How Sugar is Killing us, and what we can do to Stop it. So perhaps sugar and some forms of fat (trans, saturated?) are bad for us, but sugar is a stronger risk?

According to a 2014 article on The Telegraph, Ancel Keys and the sugar industry ruthlessly attacked Dr. Yudkin, hindering his credibility. But as the past few decades has witnessed, Dr. Yudkin may have been right all along, at least with respect to the dangers of using sugar as a substitute for fat. I’m not confidently sure which one of sugar or saturated fat is more of a risk factor for chronic illnesses — they probably both are — but if you told me to pick the greater risk factor right now, I would say sugar. The World Health Organization — a credible source, I would like to add — has recommended lowering sugar intake, but is expecting a battle with the sugar industry, as highlighted by a 2014 Nature.com article. (I highlight these dates to show how recent this whole anti-sugar movement began.) In addition, Dr. Yudkin’s work was recently revived thanks to the efforts of Robert H. Lustig, a professor at the University of California, San Francisco medical school. You can see Dr. Lustig in his YouTube video, Sugar: The Bitter Truth. Dr. Yudkin’s book was then re-published in 2012 due to growing demand, which gives an idea of how it has stood the test of time.