Thinking About Diets and Other Complex Matters

Posted on January 5, 2012. Filed under: Complexity, Diet, Uncategorized | Tags: , |

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Each January, being the season of New Year’s resolutions, it is common to find people you know discussing the pros and cons of various dietary pursuits. Individuals across the globe are eager to turn over a new leaf, get on a new bandwagon, make a new start. Yet, even with a strong will, its not at all obvious what the right recipe should be. Pick almost any diet, and you will find several experts and PHDs praising it, and an equal number panning it. You would think that with all our technology and understanding of the human body, there would be more consistency in our approach. I saw a tweet yesterday that said, “Diet guides are the political blogs of personal improvement.” This feels right. But why do discussions about something that is supposed to be scientific, feel like religious or political arguments?

I happend to “consume” three interesting pieces of content this past year on the subject of nutrition (two of these come via my partner @peterfenton). For reasons which I will disclose later, I recommend you “consume” each of them, regardless of whether you have a strong pro or con bias after hearing the descriptions.

  1. Most recently I just finished Gary Taubes new book, Why We Get Fat. For those in the know, this book is a toned down, more reader friendly, less technical version of Taubes 2008 New York Times best seller, Good Calories, Bad Calories. Taubes, a successful science journalist and researcher, obliterates the past 30-40 years of  medical rhetoric when it comes to diet and nutrition. He not only explains the physiology behind why the perspectives of the past are misguided, but also highlights the rather obvious point that “it ain’t working.”  Obesity rates are exploding. If we knew what to do, wouldn’t that be contained?
  2. The second  piece of content is a video lecture titled Sugar: The Bitter Truth, by Robert H. Lustig, a MD and professor at UCSF. Most 89 minute professorial lectures in medicine fall way short of two million views on YouTube, but Robert’s lecture is nearly at that milestone. Lustig pulls no punches in pointing directly at sugar (specifically high fructose corn syrup – HFCS) as the clear cause of the obesity epidemic we now face — not red meat, not fat, not the lack of a balanced diet, and not too little exercise. Moreover, he notes that food processors increasingly inject HFCS into a large majority of the packaged foods we feed ourselves and our children. This lecture is very compelling. As an added bonus, here is a lengthy article of Taubes reviewing Lustig: Is Sugar Toxic?
  3. Lastly, a briefer entry. This past July, Jane Brody of the New York Times, penned Counting Calories? Your Weight Loss Plan May Be Outdated. This article is a summary of a detailed 20-year research effort from five experts at Harvard that looked into the specific diets of 120,000 individuals. The main point of Brody’s title is that, based on these results, not all calories are created equal. In fact, this study found that potato chips, french fries, and sweetened beverages have a high correlation with weight gain, whereas other foods actually had correlation with weight loss. If you want to see the full study it can be found here: Changes in Diet and Lifestyle and Long-Term Weight Gain in Women and Men.
These three pieces of content had a few common themes that will likely sound “heretic” to many readers.
  1. The real enemy are sugars and carbohydrates. Taubes and Lustig make this explicitly clear. Our body is quite efficient with processing excess fat andprotein that we eat, but excess carbohydrates covert into fat on our bodies. Remember the argument that excess fats cause obesity and heart disease? Complete bullshit according to Taubea. Our physicians, our government, and our schools all rallied behind a 30-year movement to lower fat intake. As Lustig notes, it worked…we did lower fat intake…yet we kept getting fatter.
  2. Carbohydrates and sugars are addictive. Addictive the way cigarettes are. If you become a slave to massive carbohydrate intake, your body will actually crave more carbohydrates. And the bigger you are, the more you will crave. It’s hard to lose weight if you are consuming an addictive food.
  3. The calorie-in, calorie out ideal is a complete farce. How many times have you heard someone say, “all you have to do is burn more calories than you consume.” This notion that a calorie is a calorie is a calorie suggest that our bodies process each of these food types the same. Taubes and Lustig say absolutely not. Moreover, the Harvard project highlights the dangerous impact of potatoes, a seemingly harmless food that is present in every child’s school cafeteria. All food is certainly not created equal.
  4. You can’t exercise your way to thin. Simply put, you cannot burn enough calories to make yourself thin (with the exception of extreme amounts of exercise). However, with the right diet, you can lose weight without even exercising. How often do you hear that from a doctor?

Now despite what you may think, my point is not to convince you that these guys have it right. I don’t actually have a horse in this race. What I find amazing is that very educated and well reasoned experts can come to a conclusion that runs so counter to the conventional wisdom of our entire healthcare profession and our government health agencies. Moreover, despite whether you agree with their conclusion, they make a remarkably cogent arguments. Should it be this easy to prove everyone (i.e. the majority) wrong? And once again, why didn’t we have it right in the first place? And why are people so emotionally driven when it comes to their perspectives on topics such as this? (I am certain people will post comments to this blog post along the lines of “Taubes’ an idiot!”)

The human body is a complex system. Complex systems, such as stock markets, weather patterns, ant colonies, and large governments, all behave in ways that make specific prediction extremely difficult. This is because these systems involve millions of variables that are interconnected in non-linear ways that may be dynamic and dependent on potential initial states that could number in the billions. Such systems, which are well studied, are known for being unpredictable, difficult to understand, and are easy to underestimate. [One of the most influential books I have ever read is Complexity, a 1993 work by Mitchell Waldrop.]

One of the primary issues with complex systems is that people draw misleading conclusions regarding cause and effect of certain variables and how they relate to the overall system. As an example, one might note that 9 times out of 10 when variable X is set to 1, the sun is out, and so they proclaim that variable X causes the sun to come out. But the truth is they have no idea whether the sun drives the variable or the variable drives the sun. Or perhaps an entirely different variable that we are not looking at drives the sun, and all we are witnessing is ten random data points that happen to have 9-1 organization. One doesn’t really know.

But we still assume. And we try. Humans like answers and patterns. The truth is we always have. The Greek and Norse gods were early human attempts at understanding the sky, stars, and oceans. If we don’t have a specific answer we think up the best one we have, and we all glom onto it; it is better than the alternative of admitting to everyone that we don’t have a clue. Then we teach it to everyone else, and they all believe it too. Ironically, the more you come to know something through this passing of memes or ideas, the more argumentative, fanatical, or “religious” you might be. The lack of a fundamental understanding opens the door for a spiritual one. No one has an uber-passionate view on how gravity works. But politics, stock prices, and diets are a different matter. In these complex worlds, people “believe” what they cannot know.

Can we all get it wrong? When it comes to understanding complex systems, we can and we do. If you are looking for one more piece of content to consume, I recommend you watch this lecture from the late Michael Crichton: States of Fear: Science or Politics? Chrichton shows numerous examples from history where the majority misread and misunderstood complex systems. Additionally, he highlights how the mass opinion can lead to action that has well-intended but negative implications on the system. Perhaps it should go without saying, but it is particularly hard to influence a system you don’t fully understand.

By now, you may be wondering “what is my point?” Here it is. When it comes to not fully understood complex systems, it is easy to get things wrong. In fact, its easy for everyone to get them wrong. Don’t fear the new idea or the fresh perspective, and don’t believe something just because everyone else does. But watch out for the preacher with certainty — the ones that are spewing hellfire and brimstone. They are the ones most certainly to be wrong.

[Spencer Rascoff of Zillow pointed out this great New York Times article highlighting how all the smart powers that be completely missed the housing crisis, despite all the signs being there. Another example of everyone (including the experts) getting it wrong.]

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Spencer Rascoff

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35 Responses to “Thinking About Diets and Other Complex Matters”

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Awesome post! I am a professional athlete in Taekwon – Do I hear all these things about diet and weight loss each year as the season starts and we begin to train and prepare for weight cuts. Everyone has their own opinion and the truth is that each of our bodies is a very complex system. What is true and works for me may not be the same for someone else and usually isn’t. Very insightful. Right on the button I would say.

Keep it up.

Great post Bill. I can only speak anecdotally. Growing up I was always a bit skinny for my age. I could never understand quite why I stayed so thin when I frequently consumed things like cheetos, soda and bbq ribs. Intuitively, I always assumed that it was because I was a pretty active person. I make it a point to walk frequently each day as well as balance in some weekly running into the mix. I feel a bit guilty admitting it but I am still a rather skinny guy – my friends can’t understand how I can plow through a Chinese buffet or hit up for multiple runs the concession stands at sporting events. My intuition tells me that what keeps me thin is my consistent walking and jogging routine.

Hi Bill,

Thanks for this article. As you yourself have said that there are many arguments in favor and against specific food so I would like to comment about the benefits of carbohydrates which takes the form of sugars, oligosaccharides, starches and fibres and are one of the three major macro-nutrients which supply the body with energy (fat and protein being the others). There is now good evidence that at least 55% of our daily calories should come from carbohydrates. Whereas it is important to maintain an appropriate balance between calorie intake and expenditure, scientific studies suggest that: A diet containing an optimum level of carbohydrates may help prevent body fat accumulation, starch and sugars provide readily accessible fuel for physical performance, dietary fibre, which is a carbohydrate, helps keep the bowel functioning correctly.

Good post. As you point out, the post isn’t really about nutrition. It’s about how complex systems can cause us to draw the wrong conclusions, especially in the situations prone to groupthink (e.g., capital markets).
As I was reading it, I couldn’t help but think of last week’s article in the NYT about the Fed’s whiff on the impending housing crisis.

[…] Thinking About Diets and Other Complex Matters ( […]

Hey Bill, great post, I’ve been thinking a lot about this stuff lately and similarly found Taubes and Lustig to be the most insightful thinkers on the topic.

A couple of other links that may interest your readers:

– EconTalk interview with Gary Taubes, discussing “Why We Get Fat”, and particularly the issue of why diet misinformation persists

– TEDx talk by Dr. Terry Wahls – “Minding Your Mitochondria” – a remarkable story of recovery from MS after a few months of simply adhering to a nutrient-rich, hunter-gatherer diet, after years conventional medical treatment offered no relief.

[…] Perhaps we’re just seeing an order of events that makes us assume that. Bill Gurley wrote a great post about it recently, with regards to diets, where he explains this really […]

[…] friend Ross who is supporting me on my Health Rally, recommended this blog post, “Thinking about Diets and Other Complex Matters” by Bill Gurley, a VC at Benchmark Capital.  It’s a good post, and has great […]

I take your point, but when you say “watch out for the preacher with certainty” after highlighting several preachers with plenty of certainty…I’m left with the conclusion that they’re just as bad as the myths they seek to debunk. Can you lose weight just eating fats/protein? Sure. Can you lose weight counting calories? Yep. Is the truth probably somewhere in the middle? Absolutely. It generally is, which I guess is the real takeaway from your post. In a complex world (or complex thing such as the body), any extreme is almost certain to be wrong.

Speaking of which, tell Peter I’ll be near Jackson in two weeks, and happy to show him what extreme (skiing) looks like. 😉

You may be surprised, if you read Taubes he makes it very clear that he is #1, disagreeing with the previous claim, and that #2, his stuff needs further testing. He is not that hard lined. Lustig maybe.

I think you got the wrong takeaway 🙂 See

Just because these writers are pushing ideas that are unconventional, doesn’t make them extreme. The validity of any position depends on its supporting evidence, not the extent of its divergence from the mainstream.

“Can you lose weight just eating fats/protein? Sure. Can you lose weight counting calories? Yep.”

The answer to these questions is in fact “it depends”. That’s the real point about complexity. There are so many variables that will differ from one person to another, that it’s misleading and potentially damaging to suggest that, for example, anyone could lose weight counting calories.

I’ve watched up close as loved ones rigidly adhere to conventional wisdom about weight loss through calorie-counting, fat-reduction and exercise, only to see them not lose weight but actively damage their physical health and self-esteem, because these methods just don’t work given their physiological makeup. It’s utterly heartbreaking, particularly when it’s clear that there are other methods that would probably work very well for them, but are ignored because they’re unconventional.

But people become “dogmatic” and spend and waster real money. The low-fat craze of the past 30 years was a useless event.

I agree, there is an intrinsic ambiiguity in very complex systems that seems to defy capturing them in a single model. The calorie balance model has support in a number of short term experiments showing the regulation of total body mass in particular. The metabolic homeostatic model has its own body of evidence, particularly in longer term studies and observations. Neither one captures the whole picture, and I think that is reflected in practice by the observation by most people that to succeed in fitness and body composition goals they usually have to control portion sizes, activity levels, and nutrient quality, not just quantity and not just quality. Also there are different variations, especially of the homeostatic metabolic model.

There are political and rhetorical reasons I think for emphasizing one model over the other, and seeing the alternative as the root of various evils, but the reality I think is that there is a lot going on and individual learning based on our own body and habits tends to do better for most of us in the long run than picking one of these models over the other to focus on.

Thanks for a very thoughtful review.

kind regards,


Complexity is one of my favorite books too. I had the pleasure of meeting Murray Gell-Mann a couple years ago.

I believe that within my lifetime (I’m 43) we’ll discover that the “best” diet is strongly predicted by your genetic profile, and that there will be a test to help you figure out which diet is best for you.

In point #2, “read meat” should be “red meat”.

[…] Rest of the article can be read here: Thinking About Diets and Other Complex Matters […]

I would suggest reading the Book by Caldwell Esselstyn, M.D. who was able to show that a vegetarian diet with no meat, fish or chicken lowers the cholesterol as well as bad cholesterol low enough to dissolve plaques in the coronary arteries. These cultures that adhere to this type of diet have NO atheroscelerotic disease in their culture.Also you might want to see the program CNN by Sanjay Gupta. on “The Last Heart Attack”

Like I said, the point wasn’t to support Taubes. The fact that you see it differently proves my point.

I like what you’re saying. One tiny little point about gravity: what I find intriguing about gravity is that while it seems an icon of mechanistic science, hence (you’d think) one of the great discoveries of scientific materialism, gravity itself is not there. There’s nothing holding the earth in its orbit round the sun. Gravity is a concept. But space is empty. Gravity, whatever it is, is non-material. It’s spooky action-at-a-distance in fact.

This is all part of a quite different set of arguments, of course, but for anyone who likes to think the real world is fairly obviously made of detectable matter and energy, gravity should give pause for thought.

My favorite example of the complex system that is routinely underestimated is tax code and the US economy.

Legislators craft bills to try to drive consumer behavior… home ownership is a good thing, so, I know, we’ll have a mortgage interest deduction. But the economy is infinitely complex and the ripple effects of thousands of these simple incentives to drive “desirable” behavior combine into a infinitely complex incoherent mess.


I think you’re stressing the right issue : nutritionism is not (yet) a science, it’s an ideology. It promotes itself as a science but it’s basically based on unexamined assumptions, one of which is that foods are essentially the sum of their nutrient parts. Whereas food, like the human body, as you rightfully stated in your blog post, are complex systems which cannot be grasped through a mechanistic model.

If you’d like to read more on the subject, I would highly recommend you Michael POLLAN’s best seller : In Defense of Food.

Great post!

BTW, the man’s name is “Taubes” – you omit the trailing “s”.


Fixed. Thanks. I wrote it at midnight, and I am not the best self-editor.

Great post. The collective social, emotional and economic impact of these fundamental challenge is one of, if not the largest market opportunities to be found. Corporate earnings(heavily impacted by increasing costs of health benefit expenses and the largest industries in the US (Healthcare, CPG, Food/Bev and others) are all tied up in the questions raised in your blog and by these authors.

If you’ve read these, I’m sure you’ve read Michael Pollan’s books- In Defense of Food, Ominovore’s Dilemma. If not, worth checking out.

Also- while on a slightly different subject but since you are reading cool stuff about healthcare and the impact it is having our our society, you should check out Atul Gawande’s articles in The New Yorker. The Hotspotters and Letting Go (don’t read the latter in the office- tough not to shed a tear or 100). Hotspotters is pretty relevant to OneMedical (Rushika Ferndanderpulle and Tom have different philosophies and approaches but both altering the fundamental primary care model in the US).

Good stuff though- thoroughly enjoyable blog and I just got all of your recommendations which will eat up my weekend.


Hi Bill,

First of all, I am a big fan of your very thoughtful blog and your investment work in general. However, I must politely disagree with a few statements in this particular post. Sorry to have to disagree, and please allow me to explain 🙂

Credentials: I work in weight loss (co-CEO/Head of Product of — a wellness technology/weight loss startup), have read a lot of books on the subject, and regularly work with experts in the field.

A long while ago, I also read Taubes’ book and was blown away. But then, after a lot of research, I have found that many of Taubes’ arguments are just incorrect, and in fact unsupported by modern research. Because he is a journalist, he unfortunately has the perverse incentive to report sensationalist news. However, once I went back and looked up a lot of research he cites, a lot of it is not really accurate and does not say what he says it does. Taubes is a great writer which makes the book that much harder to resist.

Specifically, the largest part that’s wrong in Taubes’ book is not making a big enough distinction between refined carbs and whole carbs. HFCS — yes, terrible. Vegetables and Fruits — are excellent for you, and 99.99% of the medical establishment agrees. So sugars are absolutely an enemy, as are all other refined carbs.

It’s really hard to argue with a whole book in a blog comment, but I will point out a few things that might help:

1) Since this is a business blog, a business argument. Weight Watchers has recently revised their point system. They have a large research staff of top researchers, who have no hidden agenda except to lower the weight of their users, who also A/B tested the new system strict before rolling it out. They have made all Fruits/Vegetables “free/0 points” under the new system. Latest Wired article:

2) I recommend reading The Spectrum (, a very well researched book on diet, or Volumetrics ( Both are written by acclaimed and independent researchers. You will then see that what Taubes presents in a strawman of the medical establishment, not the real thing. The real medical community agrees that a diet high in refined carbs AND high in overall calories is to blame. The fat is only important in that it’s easy to eat a lot of calories in a small volume/mass with fat. In fact, they all also agree that you can’t exercise your way to thin. These people regularly run A/B experiments where they try all kinds of diets, and do not have some particular bias.

3) The Atkins diet has failed to produce the promised results, otherwise it would be incredibly popular by now. In fact, the opposite is true — almost nobody in the medical community respects it at all at this point. No well-established weight loss business also uses it — not Weight Watchers, not Jenny Craig, etc.

I am happy to take this off-line to telephone or private e-mail if you are curious about more. I’m also happy to tell you about our company, because I honestly really like your investment philosophy and work (i’m artem at noom dot com).

Sorry to have to disagree, Bill. I value your expertise, and in fact, I would love to work with you at some point in the future. I think, just like me a while ago, you fell prey to a well written book that has some good points, but also a lot of flaws.

Thank you for your blog.

Best regards,


I don’t view this as a disagreement, in that I don’t really care if Taubes is right or wrong. My big issue is that we gain conviction based on tiny little results and then take drastic action. For instance, I do believe that demonizing fat was a complete whiff. Kids drinking fat free milk while eating hash-browns. Nuts.

check out Michael Montignac dine Out Lose Weight

very easy read and very simple to understand. work wonders.

Basically similar to Taubes. Low glycemic index foods – less refined and processed foods.

Or read the 4 Hour body (Ferris is crazy but interesting)

It may sound conspiracy theorist, but look at all of the interests that would be hurt of the government actually did all the research and constructed proper dietary restriction guidelines and schools started to follow them – radical changes in industry. I’m quite sure coke and Pepsi 9Frito Lay) have some pretty good lobbyists.

I agree about the difficulty understanding complex systems. But when it come to calories and weight gain the simple answer may be best; calories are the same no matter their source.

At least that is what I conclude from the Bray study that we heard about this week.

This is my point. Taubes is an adamant non-believer in your point. I am not defending Taubes, just highlighting how little we actually know on this subject.

+1 to Anton’s comment. Americans are trying to scientifically talk their way out of getting fat. I lived 15 years in Europe and 15 years in the U.S., I go back and forth regularly and I’m constantly reminded that you are what you eat and many Americans are hooked on cheap processed foods. For instance, the food supply chain in the U.S. is such that most people haven’t had tomatoes and cucumbers that actually have taste and are fully ripe and they don’t even know it. That’s pretty basic and doesn’t require a PhD.

as I said, I am not hardcore on what right in diets. More interested in the ability for their to be controversy.

That was a great article and mirrors a lot of my own personal experience.

Last year when I decided that I was going to make the leap from sprint triathlons to half Ironman I sat down and really thought through the whole process. My immediate conclusion was that I simply didn’t have time to train a 260lb 47 year old body into the kind of shape required to reliably finish.

So I sat down and did a *ton* of reading about diets, food, and how endurance athletes eat. Note that I did not address exercise and training as I know how to do that stuff, more-or-less.

My a-ha moment was that I realized that most successful endurance athletes had three things in common:
-> Lots of small meals every day
-> Reliance on low fat protein (chicken or turkey, not bacon or steak)
-> Natural foods

It is clear that a calorie is not a calorie and that there are balance issues, but in general you do, actually, have to take fewer in than you burn if you want to lose weight. (Over the medium run, not a day or two.)

I spent the next year losing 55 lbs (woot me) by eating a bit better every day -> whole grains over processed, eliminating almost everything processed from my diet (makes travel hard, let me tell you), eliminating most chemicals, reducing simple carbs, learning to really watch and understand what I was eating, etc.

The minor realization I came to in spring was that I really have to replace my calories, especially my proteins, after exercise. So now I tell people that I don’t exercise to lose weight, I exercise to raise my metabolic rate and improve my digestion so that a proper diet makes me skinnier and faster.


Interesting piece Bill – I wonder what this says about your approach to investing? I read Taube’s book and found it interesting and indeed compelling. I also listened to some of Lustig’s lecture on Sugar. I will check out the other references you’ve given. Where Taube lost me was on his dietary recommendations at the end of the book. Seriously – there’s no way I’m going to lie on that bed of nails! I have however, consciously cut back on carbs and sugars and allowed a little more fat and meat in my diet. I lived in France for 5-6 years and I’ve lived in the US for almost thrice that – the French diet is one of the richest and sweetest in the world – so why are they so damn skinny and lean? What can be learned by Americans from this? Some of the answers may lie in the fact that the French really enjoy their food. It is not a convenience. They take the time to prepare, share and linger with conversation over their meals. And when they do, the portions are rich BUT small! They also would prefer a glass of wine with their meals rather than an enormous soda drink, that’s gulped down and ready for a free refill. When I first arrived in the US I couldn’t believe how much food was served up. Who could possibly want to eat that much? But it seems that we Americans love everything big, including our food portions and what we can’t eat we take home in “doggy bags”, a concept which doesn’t exist in France. In the US, fast food is all around us, its cheap and we grab it on the go, sometimes without even getting out of our cars. We eat in our cars and at our desks or in front of the television. We don’t eat slowly and we barely know what we’ve eaten when we finish. I think a cultural change in attitude towards food should be explored as part of the mix of food science here. It might uncover not just interesting facts about weight gain or loss (the physical) but also the impact on our happiness (the spiritual). Thanks for a great post!

I was blown away by Lustig when I first saw his presentation last year. I forwarded it to anyone that I cared about. Makes so much sense. Thanks for the other links and content.

Amazingly well written blog post. Truly a pleasure to read.

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    …focusing on the evolution and economics of high technology business and strategy. By day, I am a venture capitalist at Benchmark Capital.


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