By Marika Sboros

Unless you’ve just beamed down from another planet, you’ll know that US science journalist Gary Taubes has a new book out. It’s called The Case Against Sugar. I haven’t read it yet. I’ve only read the reviews, most of them favourable – except one. It is Bad sugar or bad journalism? An expert review of “The Case Against Sugar”. The author is US neurobiologist and obesity researcher Dr Stephan Guyenet.

(EDITOR’S NOTE: I’ve since read it. It’s riveting and definitely vintage Taubes. It’s an investment in long-term health.)

Guyenet’s review is not a complete hatchet job. First, he damns Taubes with faint scientific praise. Then he sticks the knife straight into Taubes’s research heart. Guyenet says that Taubes “misunderstands (or chooses not to apply) the scientific method itself”. He accuses Taubes of “extraordinary oversight”. He also says that Taubes ignores “inconvenient facts”.

US physician Michael Eades has read the book – twice – and reviews it in a post on his Protein Power blog. He has given me permission to republish it here. He comes to very different conclusions compared to Guyenet. Here’s the sweet and the sour of reviews.

First things first, before Eades’ review. Guyenet has an agenda, which he probably should have declared. He appears still mightily miffed at Taubes after a public lecture Guyenet gave way back in 2011. That was because Taubes asked Guyenet rambling and belligerent questions afterwards. He also gave Guyenet gratuitous advice on how to do his job better. That didn’t go down well either with Guyenet or his supporters. (Scroll down below to see a video of the incident. Taubes comes in at 35.23 minutes.)

Gary Taubes

Eades begins his review with a lengthy email to fellow blogger Richard Nikoley who asked for his response to Guyenet’s review. Eades knows all about the 2011 incident between Taubes and Guyenet because he was there. He also says that Taubes apologised to Guyenet, who appeared to accept it.

However, Guyenet’s review suggests that while he may have forgiven Taubes, he hasn’t forgotten the slight. It clearly still rankles.

Another source, who prefers to remain anonymous, tells me it was just a “clash of scientific class cultures”.  Taubes comes from the physics world where they routinely “yell, scream and call each other names and their ideas stupid. Then they laugh and go out for a beer together.”

Guyenet comes from the polite nutrition world. “They thought Taubes was horribly boorish.”

In his review, Guyenet describes The Case Against Sugar as “a journey through sugar history and science”. However,  the lens of Taubes’s personal beliefs distorts it “heavily”, he says.

By that metric, the book is “not journalism, but advocacy”. It will be misleading to a general audience that has little basis for evaluating its claims, Guyenet says.  He concedes that the book “does contain some interesting history” – but only for readers willing to take The Case Against Sugar “with a case full of salt”,

Taubes has already responded in The Case against Sugar Isn’t So Easily Dismissed.

Eades starts off his email to Nikoley with a favorite quote from Bertrand Russell: “The stupid are cocksure while the intelligent are full of doubt.”

“I like (the quote),” Eades says, “because we all are like atomic particles. We change states constantly. In some aspects of our lives and on some subjects we are intelligent. In others, we are stupid.”

Consequently, we are either “cocksure or full of doubt, depending upon our state”.




Eades talks of the potency of confirmation bias and how “almost impossible it is to overcome”.  Confirmation bias suffuses us all, he says. That includes himself. Thus, he never knows for absolute certain whether he is “on the right side of any argument or not”.  In other words, whether he is “cocksure or full of doubt”.

Eades relates his own extensive low-carb journey, including personal experience with effective weight loss. He sets the scene for his review of the book with an open admission of his own bias. He says he was initially reluctant to address Guyenet’s review. Eades quotes from a book by Scott Adams, which he says changed his mind about engaging in these kinds of things:

‘If your view of the world is that people use reason for their important decisions, you are setting yourself up for a life of frustration and confusion.  You’ll find yourself continually debating people and never winning except in your own mind.  Few things are as destructive and limiting as a worldview that assumes people are mostly rational.’

That settled, he addresses – and decimates – Guyenet’s review. He says that many of Guyenet’s criticisms would be “on point” if Taubes hadn’t already admitted to them in the book.

“So they’re not really valid criticisms. It’s not like Gary is trying to pull the wool over anyone’s eyes.

Here is Eades’ take on The Case Against Sugar, and one of the questions, which Taubes proposes: is there an amount of sugar that people eat, which becomes bad for health? 

By Michael Eades

Does sugar damage metabolic flexibility? Scientists define metabolic flexibility as the ability of skeletal muscle to switch between the oxidation of lipid as a fuel during fasting periods to oxidation of carbohydrate during insulin-stimulated periods.

Dr Michael Eades

More simply put, metabolic flexibility is a measure of the body’s ability to deal successfully with all incoming foods, irrespective of macronutrient composition. If you’ve got a lot of metabolic flexibility, you can pretty much chow down whatever you want and not suffer any immediate consequences.

If you eat fat, your body burns some but stocks most away till later. Same with carbs. You burn what you need, then store the rest as glycogen. What about both fat and carbs? Generally, you burn the carbs first, store the rest and store most of the fat. Thus, the point is if you’ve got good metabolic flexibility, you can eat most anything and not suffer immediate consequences.

Unfortunately, unlike love and herpes, metabolic flexibility isn’t forever. Most of us experience a decline in metabolic flexibility as we age. But it takes a while, which is why children seem to be able to eat anything they want without paying the piper (immediately, at least).

Most of us adults aren’t so lucky. Sadly, many children aren’t either. Rates of type II diabetes (formerly called adult-onset diabetes) are now rising in children and adolescents.

Under normal metabolically flexible conditions, eating carbohydrate stimulates the pancreas to release a little insulin. This drives oxidation of the carbs for immediate energy the body needs and storage of the rest. When metabolic flexibility doesn’t work so well, the carb meal stimulates insulin release, which often isn’t enough to store away all the carb and the blood sugar rises. The pancreas releases more insulin, which may or may not be enough to get the blood sugar down.

Ultimately, those who lose metabolic flexibility can find themselves having both elevated insulin (hyperinsulinemia) and elevated blood sugar. We call this type 2 diabetes. It is often associated with obesity and other disorders which doctors collectively call the metabolic syndrome.

There is a continuum running from mild glucose intolerance to full-blown diabetes and everything in between. The end result we diagnose as glucose intolerance, diabetes, metabolic syndrome or whatever. The cause is a decrease in metabolic flexibility.

Dr Stephan Guyenet

No one really questions the idea of metabolic flexibility or its decline with age. They do question why it happens. Why the decline? Why do some people have a minimal fall off with age, while others have a massive fall off and succumb to diabetes, obesity and the rest? What makes people convert from being metabolically flexible to being metabolically INflexible?

Since most people with metabolic inflexibility respond quickly and often completely to carbohydrate restriction, many (myself included) believe that carbohydrate overconsumption may be the cause.

Those of us who believe in this theory fall into one of three camps. One I call the Yudkin camp (after the British physician and nutritionist John Yudkin);  the second the Cleave camp (after Thomas L Cleave, another British physician); finally, the all-carbs-are-bad camp that I don’t have a published Brit author to name after.

Yudkin thought sugar was the initiating problem. Cleave thought refined carbs, mainly wheat and sugar, were the initiating problem. Those in the third camp believe all carbs are bad.

The camps differ in what they believe is the cause, the triggering event, so to speak. However,  they all agree that once the problem sets in and the body loses metabolic flexibility, a low-carb diet is the only way to treat it successfully.

This is where Gary Taubes’s book, The Case Against Sugar, enters the picture. He makes the Yudkin case, although using a ton more research than Yudkin had available to him during his lifetime.

Gary musters a mountain of evidence that once sugar is introduced into a society, nothing much happens at first. Diabetes, the signature feature of metabolic INflexibility, is rare.  As the amount of sugar people eat increases, cases of diabetes start popping up.

Ultimately, when the sugar consumption is at high levels (in the US it peaked in 1999 at about 90 pounds of sugar per person per year and has fallen off slightly since), diabetes becomes epidemic.

(NB: Remember, the 90 pounds per person per year is an average. I doubt that I eat five pounds of sugar per year. That means someone else is eating 175 pounds per year to make the average work. It is those people who are doubtless filling up diabetic wards.)

Stephan Guyenet and others have attacked Gary because the data he musters comes from observational studies and short-term, often poorly done RCTs. The reason is that this is all the data that are available.

To truly nail this down, scientists would have to randomise people into two groups. Researchers would expect subjects in one to eat 100 pounds of sugar per year, while the subjects in the other group would eat almost no sugar (or a significantly lesser amount). The study would have to last for years to realise a significant outcome.



Ethical issues aside, a study like this would be enormously expensive and impossible to monitor accurately. It’s one thing to randomise people into a study and have them not eat sugar for a month or six weeks. It’s entirely another to get them to forsake it or gorge on it for six years  – or however long it would take for meaningful data to emerge.

You have to do it kind of like the studies on smoking were done. For ethical reasons, you couldn’t randomise non-smokers into a group and make them start smoking to compare outcomes with those who continued to smoke. Researchers had to rely on observational studies and animal studies, all of which strongly implicated smoking as a major driver of lung cancer.

The Case Against Sugar is a standard Taubesian work. It is compulsively readable and filled with all kinds of engaging and thought-provoking history. He veers off here and there to discuss the invention of ice cream and origins of candy and soft drink empires that exist today.

And that’s not to mention the breakfast cereal industry, which, unfortunately, was the source of many of my own calories in my youth.


Another fascinating rabbit trail Gary takes us down is the unholy alliance between Big Sugar and Big Tobacco. By blending tobacco the industry cured two different ways – both involving sugar – cigarette sales skyrocketed. The addition of sugar to tobacco made cigarette smoke easier to inhale and vastly more addictive.

Before I wrote the email that kicked this post off, Cato Unbound, a debate or discussion forum that is part of the Cato Institute, asked Gary to write an essay based on his findings on sugar. The editors of Cato Unbound then found three people to write responses.

They  were Yoni Freedhof, a Canadian physician, (Freedhoff is best known to readers of this blog as the physician who took the video of Kevin Hall and asked the fawning questions), Guyenet, whom we met in the email above, and Terence Kealy, whom I don’t know but is a physician and biochemistry researcher.

After all the critiques were in, the editors allowed Gary to answer them all. I’ll let readers determine for themselves whether Gary adequately answered his critics, the main one of whom is Dr Guyenet.

Here is Gary’s essay: Unintended Consequences, Special Interests, and Our Problem with Sugar

Stephan Guyenet’s response: Americans Eat Too Much Cake, but the Government Isn’t to Blame

Yoni Freedhof’s response: Unintended Consequences, Special Interests, Sugar, and a View from the Clinical Trenches

Terrence Kealey’s response: Putting Nutrition Claims to the Test

Gary’s response to the above: The Case against Sugar Isn’t So Easily Dismissed

Since I started working on this blog post, two more responses have come in. One more from Dr Guyenet: Extraordinary Claims Require Extraordinary Evidence. And another from Dr Freedhoff: Complex Multi-Factorial Problems Tend not to Have Simple Singular Causes

My advice is to not sit on the sidelines as observers to this spat.  Read The Case Against Sugar and come to your own conclusions based on how strong you believe the evidence to be.

Editor’s note: Guyenet has responded to Foodmed.net: “Taubes’s comment at AHS (Academy of Health Sciences) in 2011 was irritating but nothing more. He has since apologised for it, and I accepted his apology. The suggestion that his comments six years ago underlie my negative review of his book The Case Against Sugar is absurd. The real reason why I react to his writing in a negative way is that it is unscientific and anti-scientist, which I made very clear in my review. The scientific community is fed up, and I’m one of the few people with both the knowledge and the platform to push back and provide a more scientific alternative to the public. Taubes has been aggressive, insulting, and inaccurate in his portrayal of researchers who he disagrees with, so I have no sympathy for whining when he gets a negative review from the scientific community.”