Hi Anthony,

I read your They’re All MAD! ebook recently, nice work! You do an excellent job of showing how personal prejudice and blind dogma determine so much of what is presented to the public as ‘scientific’ diet and health information. Thanks for making it freely available.

Your experiences with the low-carb “MAD” movement got me thinking: I remember you wrote years ago about a study comparing the cognitive effects of a ketogenic low carb-diet with a non-ketogenic diet, and how the keto diet showed negative effects. Have you come across any more research on this? I can’t help but wonder if the weird behavior demonstrated by so many online low-carb followers is related to the diet they follow.

Best,

HD

Great question – and after my experiences with the online low-carb ‘community’ and a certain of their incoherent ‘gurus’, I couldn’t help but wonder the same thing. These people seem to have a far greater than normal capacity for denying reality, and for going off like a wayward firecracker when someone presents views that contradict their cherished dogma. And their penchant for performing all manner of mental contortionism in order to rationalize scientifically untenable beliefs would garner envy from even the most fanatical Creationist.

Is this a case of the diet causing people to behave irrationally, or irrational people being attracted to this style of eating? Or is the behavior of the low-carb ‘community’ just another example of the human tendency to form sectarian groups that promulgate an either-or mentality, that reinforce their own beliefs by selectively feeding each other with supportive ‘evidence’, and reacting with hostility towards those who present opposing viewpoints and non-supportive evidence?

After observing the antics of low-carbers and other dietary sectarians, and reviewing the research examining the actual effects of diet on mood and cognition, I’m inclined to think that a combination of all the above factors is in play.

This Is Your Brain on…Food

There is little controversy that food can affect one’s mental functioning. The mere act of eating itself can cause changes in mood and cognition, regardless of dietary composition. It is well established, for example, that skipping breakfast results in a prolonged hypoglycaemic state that results in poorer cognitive performance.

As for varying the macronutrient composition of one’s diet (ie, varying the amounts of protein, fat and/or carbohydrate), there has been a plethora of studies examining the effects of single meals on subsequent mood and cognitive function. Although the results are not universal, common findings are increased drowsiness and greater calmness after high-carbohydrate meals, and increased alertness and feelings of tension after high-protein meals.

Many of these studies compared meals of polar opposite fat and carbohydrate composition. A study comparing diets of similar protein content that included a balanced “medium” fat and carbohydrate meal in addition to high-carb/low-fat and low-carb/high-fat meals reported superior mood and cognitive results from the balanced meal[Lloyd HM]. Maybe your mum was onto something when she told you “all things in moderation”…

A study that compared a high-carb meal, a high-protein meal, or a meal containing equal amounts of protein and carbohydrate found the latter two provided superior cognitive performance after the meal[Fischer K]. In another study comparing high-carbohydrate, high-protein, or balanced meals, only the high-carbohydrate meal worsened post-meal fatigue and cognitive performance[Spring B].

Short-term comparisons also indicate that the type of carbohydrate consumed has an affect on subsequent cognitive performance; low-glyemic index (GI) carbohydrates produce better memory recall than high-GI carbohydrates[Benton].

The problem with these acute short-term studies is, while they show us what happens in the hours following a meal, they don’t demonstrate the potential dietary-induced changes that may occur in one’s mood and cognitive state over the longer term. Fortunately, there have been a number of studies looking at the longer-term cognitive and psychological effects of lower- versus higher-carbohydrate diets. These studies have returned some rather interesting results.

Longer-term studies.

In a study published in the International Journal of Obesity, overweight women consuming either a ketogenic or non-ketogenic 600-calorie/day low-carbohydrate diet were monitored for twenty-eight days. This study was performed under metabolic ward conditions, giving us the confidence that the subjects actually followed the diets they were assigned. Contrary to what the metabolic advantage promoters would have you believe, there was no statistically significant difference in weight loss between the two groups.

However, weight loss was not the only outcome measured on this diet. The study also examined the effect of ketogenic versus non-ketogenic diets on cognitive function. The researchers found that, in the first week, ketogenic dieters performed far worse on the trail making task, a widely used test that measures a range of neuropsychological skills including letter and number recognition, visual scanning, motor speed and sequencing ability. After the first week, the ketogenic group began to improve their test results, but by the time the study concluded at 28 days, their results were still lagging behind the non-ketogenic dieters[Wing].

In 1982, researchers from the University of Vermont compared two 827-calorie diets, one containing zero carbohydrate, the other containing 29% carbohydrate (60 grams). So again, what were effectively being compared were very low-calorie ketogenic and non-ketogenic low-carb diets. Eight obese women were randomly assigned to follow one of the diets for 6 weeks. They were admitted to the Clinical Research Center of the University of Vermont College of Medicine for the duration of the study. All the women were hospital employees and they were allowed to continue their jobs, but they slept and took all meals under supervision at the center. The psychological tests administered included the state-trait anxiety inventory-trait anxiety (STAI-T) and the Beck depression inventory (BDI) at baseline and at the end of the diet periods. Appetite and emotional adjustment were also assessed via daily self-rating scales. The scale categories included depressed mood, anxious mood, interpersonal sensitivity, self-esteem, diet attitude, and appetite.

After six weeks, STAI-T scores showed the subjects in both groups were significantly less anxious. Although the decrease appeared to be greater during the carbohydrate-containing diet, it was not statistically significant. Depression, which was within the normal range at baseline, remained the same. As for the self-rating scores, there was a consistent, but non-significant, trend in both groups for deterioration in mood, diet-related attitude, and self-esteem during the first week on both diets. This was followed by an improvement after six weeks so that psychological adjustment was equal to or better than that at the start of the study. There was no significant difference between the two diets for ratings of hunger or craving[Rosen].

Although ketone concentrations were significantly higher in the zero carbohydrate group, there were no differences in fat loss between the two groups, further confirming the fallacy of the “ketosis = greater fat loss” theory. The zero-carbohydrate group did however experience something the non-ketogenic group didn't: namely, significantly poorer exercise performance[Bogardus].

A more recent but slightly shorter study by Tufts University researchers involved nineteen women who self-selected a low-carbohydrate or a diet similar to that recommended by the American Dietetic Association (ADA diet). Individuals who chose the low-carb diet received instructions to limit their daily carbohydrate intake to zero for one week, 5-8 grams during the second week, and 10–16 grams in the third week. Before, during, and after the diets, participants completed the including the Profile of Mood States questionnaire and a battery of cognitive tests. During complete withdrawal of dietary carbohydrate, the low-carbohydrate group performed worse on memory-based tasks than ADA dieters. These impairments were eliminated after reintroduction of carbohydrates. Low-carbohydrate dieters reported less confusion and responded faster during an attention vigilance task than the ADA dieters[Danci].

Researchers from the CSIRO (Commonwealth Scientific and Industrial Research Organisation) in Adelaide, Australia compared the effects of a low-carbohydrate, high-fat diet with a conventional high-carbohydrate, low-fat diet on mood and cognitive function. The low-carbohydrate diet provided 35% of total energy as protein, 61% as fat, and 4% as carbohydrate; the high-carbohydrate diet provided 24% of total energy as protein, 30% as fat, and 46% as carbohydrate. The diets were designed to be isocaloric and to have a moderate calorie restriction of around 30% for 8 weeks.

After eight weeks, mean scores on the Beck Depression Inventory, Spielberger State Anxiety Inventory and Total Mood Disturbance of the Profile of Mood States psychological questionnaires had improved similarly on both diets. Working memory test scores increased similarly in both groups, while speed of processing improved to statistically significantly greater degree on the high-carbohydrate diet[Halyburton].

Noting that most studies on the topic were relatively short in duration, the CSIRO researchers later published a 12-month report[Brinkworth]. After one year, both groups lost the same amount of weight (13.7 kg) and experienced similar reductions in plasma glucose and serum insulin levels.

Scores on the Beck Depression Inventory, Total Mood Disturbance of the Profile of Mood States and anger-hostility, confusion-bewilderment, and depression-dejection subscales of the Profile of Mood States decreased (improved) initially in both diet groups and tended to remain low in the high-carbohydrate group but rebounded toward baseline levels over time in the low-carbohydrate group. At 12 months, scores on the Profile of Mood States subscales of anger-hostility, confusion-bewilderment, and depression-dejection and the Total Mood Disturbance of the Profile of Mood States score were significantly lower in the high-carbohydrate group than in the low-carbohydrate group. On the Spielberger State Anxiety Inventory, differences were also evident between the diet groups at 12 months. A similar pattern of change was evident on the Beck Depression Inventory, although the difference between the diet groups did not reach statistical significance (P = .11). Both diets had similar effects on working memory and speed of processing.

So here we have the longest-running study so far, and it showed significantly worse psychological outcomes for the low-carbohydrate diet. Even though the low-carb group fared worse, the CSIRO researchers point out that mood state scores on average for both groups at baseline and throughout the study remained within the normal range for healthy adults. The low-carb group, it seems, was simply at the more angry, confused, and dejected end of the normal range…

The researchers were quick to point out that the present findings were limited to “healthy, obese, young to middle-aged adults with normal mood state and cannot be generalized to clinical populations”. Given the evidence reported thus far, those with a tendency towards anger or depression, or those suffering from any other psychological condition should steer clear of ketogenic low-carb diets. I say ketogenic, because all the studies showing negative effects have utlized ketogenic variants of low-carbohydrate diets (ie, those supplying less than 50 grams of carbohydrate daily). As we've seen, some of the studies actually compared ketogenic and non-ketogenic low-carb diets and found no evidence of ill-effect with the latter.

If you’ve been following a ketogenic low-carbohydrate diet and have found yourself lately feeling more depressed, anxious, moodier, nastier, angrier and/or grumpier, maybe it’s time you started tucking into some good old low-GI carbs from nutrient-rich plant foods. Relax, your body won’t explode or collapse from carbohydrate poisoning…we humans have only been safely eating naturally occurring carbohydrate foods for, well, our entire evolutionary history.

Well, so far it’s not looking too good for ketogenic low-carbohydrate diets. They tend to produce poorer overall cognitive and psychological outcomes than higher carbohydrate diets, and no study has shown they produce superior overall effects.

Except one.

Atkins to the Rescue?

McClernon et al compared overweight individuals following a low-fat/high-carbohydrate diet with those following the Atkins Diet. The Atkins dieters were instructed to consume less than 20 grams of carbohydrate initially, and were permitted to increase this amount incrementally as the study progressed. The data covered a period of 6-months.

The paper analysed both physical and psychological symptoms experienced by the two groups, including "negative affect", "fatigue", "somatic symptoms", "physical effects of hunger", "insomnia", "hunger", and "stomach problems". All these reported outcomes were more favourable on the low-carb diet, with the exception of insomnia, which scored higher in the low-carb group throughout most of the study[McClernon].

So here we have the only study that has reported significantly more favourable psychological results for a low carbohydrate diet, and guess what? The study was funded by the Robert C. Atkins Foundation and one of the listed authors of the paper is none other than the late Dr. Robert C. Atkins. Hmmm…

Not only that, but instead of using widely accepted and validated psychological questionnaires, the researchers of this study chose to use the “Atkins Health Indicator Test (AHIT)”. What on Earth is the AHIT? According to the researchers, it “asks about the presence of 56 symptoms”, although in this study, 23 items "did not load onto any factor, likely owing to very low rates of responding on these items".

Any impartial observer would feel much more comfortable if the researchers had used established psychological tests devised by detached researchers, rather than a non-validated one invented by the promoter of one of the diets being studied. And in this case, such concerns are more than justified; in his 1992 book Dr Atkins’ New Diet Revolution, Atkins clearly displayed a woeful inability to impartially report evidence concerning the comparative weight loss effects of high versus low-carbohydrate diets (*for more details, see the "Notes" section below).

As another group of researchers commented, this study “was limited in that mood was not assessed using validated scales. Rather, they used a symptom checklist developed by practitioners specifically for evaluating and treating individuals using an [low-carbohydrate] diet for weight loss that may have biased the result toward a positive effect of an [low-carbohydrate] diet as opposed to an [low-fat] diet”[Brinkworth].

Another glaring discrepancy in this study was the fact that only the Atkins dieters received nutritional supplements. It is well known that nutritional deficiencies, commonplace among those following Western diets, can negatively affect mood state. Omega-3 supplements, for example, have been shown to favourably effect symptoms of hostility, depression, and even serious psychiatric conditions such as schizophrenia. Omega-3 supplements were among the supplements given to the Atkins dieters but not to the low-fat dieters.

Another potential confounding factor is that the low-carb and low-fat groups clearly did not consume isocaloric diets, as the low-carb group lost almost twice as much weight (−12.9 kg vs −6.7 kg). Although attempts were made by the authors to control for weight loss in the statistical models because of the association between weight loss and psychological well-being, the possibility cannot be dismissed that the greater weight loss with the low-carbohydrate diet accounted for the greater reported reductions in negative affect (so-called “multivariate analyses” can never take the place of randomized controlled trials where such confounding factors have been removed).

So to sum it up again, the only study showing superior psychological effects for a very low-carb diet was conducted by Atkins-sponsored researchers, one of whom was Atkins himself, used a psychological questionnaire designed by Atkins, and administered nutritional supplements including omega-3 fats to the low-carbohydrate group only. When it comes to impartial, tightly controlled evidence for any psychological or cognitive benefit of low-carbohydrate diets, this study fails miserably.

It’s worth mentioning another study that, at first glance, appears to support favorable psychological outcomes on a low-carbohydrate diet. This study was also conducted by CSIRO researchers in Adelaide and published in 2007. The researchers assigned women with polycystic ovary syndrome to follow either a low-protein/high-carbohydrate diet or a "high-protein low-carbohydrate diet" for 12 weeks[Galletly].

After 12 weeks, there were no differences between groups in weight loss. In the "high-protein low-carbohydrate” group, there was a significant improvement in ratings for depression and self-esteem, while no significant change was noted in any psychological measure in the low-protein/high-carbohydrate group. Before low-carb advocates start running (or is that waddling?) around the room, whooping and hollering in victory, one important discrepancy with this study should be pointed out.

The low-carbohydrate diet wasn’t actually a low carbohydrate diet.

Both diets were designed to deliver just over 1400 calories per day. The high-carbohydrate diet contained 15% protein, 30% fat and 55% carbohydrate, while the “low-carbohydrate” diet provided 30% protein, 30% fat and 40% carbohydrate. In this study, that equates to 143 grams of carbohydrate daily, well above the commonly cited low-carbohydrate threshold of 100 grams and even further north of the widely accepted ketogenic threshold of 50 grams. While folks like Barry Sears who promote “30/30/40”-type diet plans might be able to squeeze some marketing mileage from these results, they cannot be transposed onto the dietary regimens promoted by popular low-carbohydrate authors.

Atkins Diet Presses Woman’s Panic Button

It bears keeping in mind that the above studies were conducted in generally healthy volunteers carefully screened to exclude those with psychiatric problems. As such, these studies don’t tell us what would happen to individuals suffering behavioural or psychiatric conditions when they attempt to follow ketogenic low-carbohydrate diets.

A recent case report gives us an insight, and it isn’t pretty. The 2006 report, published in the journal Psychosomatics, described a woman with well-controlled panic disorder who developed a return of her panic symptoms after starting the Atkins diet. She had been diagnosed at the age of thirty-seven with panic disorder, which was successfully managed for the next ten years with daily usage of alprazolam and sertraline. During this time, she had only two full-blown panic attacks, rare limited-symptom attacks, and “normal functioning”.

At the age of forty-seven and weighing 252 pounds, the patient decided to go on the Atkins diet. The next day, she began to experience an internal sensation of “shakiness”, which progressed to a fully-fledged panic attack later that day. She increased her sertraline dose in an attempt to control the symptoms, but continued to have frequent panic attacks. Over the next four weeks the patient experienced a marked increase in her baseline anxiety level.

Although she believed her diet was connected to these symptoms, she did not stop the diet because she had lost over seven kilograms. Eventually she decided to quit the diet and resume eating carbohydrates. Her symptoms improved that same day, and all symptoms disappeared after several days. According to the report’s author, Dr. Mark J. Ehrenreich from the University of Maryland School of Medicine’s Department of Psychiatry, she continued to do well over the following years[Ehrenreich].

Interestingly, last year I received an email from a friend in New York, telling me about a fellow at his gym who experienced anxiety attacks while on the ketogenic “induction phase” of the Atkins Diet. When this fellow reported his experiences on a popular low-carbohydrate forum, he was told to “suck it up” and that “it wasn't the diet”. It goes without saying that Internet forums devoted to a specific dietary pattern are quite possibly the worst possible places to seek impartial and factual information about problems with that diet; the typical response from other posters is denial, rationalization and often an attempt to apportion blame for the diet’s shortcomings onto the dieter instead; “that problem couldn’t possibly be caused by the diet…you must be doing something wrong!”

The dieter is indeed doing something wrong: following a nutritionally inadequate diet promoted by biased and clueless individuals who have not thoroughly and impartially researched said diet.

This Is Your Brain on Ketones

The ketogenic variants of low-carbohydrate diets have, overall, returned poorer psychological and cognitive results in research than higher carbohydrate diets. Unfortunately, authors such as Atkins, Eades, Agatston et al, whose plans kick off with a 2-week extremely-low-carbohydrate phase, have successfully convinced many dieters that there is something special about ketosis. In a way, they’re right – no other dietary strategy seems to so quickly decimate sports performance and induce lethargy, constipation, dizziness, heart rhythm irregularities, mineral deficiencies, rotten breath and repulsive body odor than ketogenic diets. In that aspect, they are indeed a standout. But when it comes to the widely pronounced claim that they bring on greater fat loss, there is not a skerrick of controlled scientific evidence to show this is true. What we do have are numerous tightly controlled metabolic ward studies showing no greater fat loss on ketogenic (and low-carb in general) diets (see chapter 1 of The Fat Loss Bible for the most detailed available discussion of these studies). However, low-carb diet gurus never discuss this research with their followers, except for a couple of notable exceptions who selectively cite what appears to be favourable ward research and ignore or dismiss non-supportive ward studies (see “Notes” below).

So What Does This All Mean?

OK, let’s return to the original question. Do the psychological effects of ketogenic diets contribute to the irrational and sometimes downright bizarre behavior exhibited by many online low-carb devotees?

Because I can’t get inside the heads of all these people (and probably wouldn’t want to even if I could!), I can’t say with any scientific sense of certainty. What I will say is this: diets that are inherently unbalanced seem to be associated with more than their fair share of extremist behavior compared with more moderate plans (as an example, I’ve yet to see any noteworthy level of shrill behaviour from followers of “Zone” or “Mediterranean”-style diets). Ketogenic diets are characterized by extremely low-carbohydrate intakes that may alter serotonergic expression[Christensen L] and induce or exacerbate deficiencies in important minerals including potassium, magnesium and selenium.

Similarly, vegan and fruitarian diets, whose followers have also been known to engage in some rather whackopathic behavior, can induce various nutrient deficiencies, including those of B12 and essential fatty acids (both crucial for neurological health). Tom Billings has talked at length about the less-than-sterling conduct evidenced by die-hard followers of these regimens:

http://www.beyondveg.com/billings-t/claims-cred/claims-cred-1g.shtml#skepticism,%20golden%20cage

http://www.beyondveg.com/billings-t/claims-cred/claims-cred-1e.shtml#rose-colored%20glasses

http://www.beyondveg.com/billings-t/claims-cred/claims-cred-1b.shtml#examining%20dogma

Virtually everything Billings has reported in his observations can also be applied to the low-carb movement. Like vegans, low-carbers often display an us-versus-them mentality, a negative feature that is of course hardly exclusive to diet sectarians. Human beings in general are imbued with this trait, something that politicians and other professional manipulators are never slow to exploit. Back in the Stone Age, such a trait may have conferred survival advantages by reinforcing group cohesion and resistance to hostile tribes. In our modern complex society, it allows leaders to exploit such phenomena as patriotism and nationalism to cajole populations into highly destructive wars, the true agendas of which are often very different from those presented for public consumption.

In the dietary arena, this us-versus-them mindset leads to the development of absolutist attitudes that cause dietary devotees to brand outsiders as inferior or even evil. In the vegan arena, this may translate to the belief that avoidance of meat is virtuous while those who eat meat are “bad” (indeed, “Meat is Murder” is a popular catchcry among the vegan animal rights movement). Vegans readily embrace and cite research that appear to support their beliefs, while research unsupportive of vegan diets is reflexively derided as being biased, corrupt, and the product of dairy/meat/egg industry-sponsored researchers.

Low-carbohydrate followers meanwhile, have been so thoroughly indoctrinated about the “evils” of carbohydrates that they frequently exhibit a phobic attitude towards this naturally occurring macronutrient. Seriously, I’ve read Internet posts where the author was fretting as to whether or not they should eat liver because of it’s carbohydrate content – a miniscule five grams of glycogen-derived carbohydrate per 100 grams of cooked liver! Low-carbohydrate ‘gurus’ have so successfully convinced many of their followers that extremely-low carbohydrate ketogenic intakes are superior for fat loss that many of these hapless devotees will often completely shun carbohydrates and endure constipation (a favorite topic of discussion on low-carb forums), repulsive breath and body odor, irritability, and numerous other unpleasant symptoms.

Low-carbohydrate devotees routinely exhibit a deep sense of distrust and often hostility towards those who make favourable public commentary about carbohydrates. Low-carb commentators will scour through research papers unsupportive of their beliefs with a fine-toothed comb, looking for any and every possible flaw or discrepancy that could be used to discount the results. Meanwhile, even the sloppiest of evidence is embraced with open arms and little if any critical analysis when it returns results supportive of the low-carb paradigm (again, see the “Notes” section below for some classic examples of this behavior by prominent low-carbohydrate authors). Research supporting high-carbohydrate intakes or unsupportive of popular low-carbohydrate dogma is routinely derided as the biased product of researchers blindly committed to the mainstream low-fat/high-carbohydrate dogma. When unable to refute their opponents’ scientific arguments, low-carb advocates have shown little reluctance to engage in wholesale slander of their target’s personal character, habits and mental competency. “When you can’t beat them, slander them!” appears to be a highly popular modus operandi among low-carb defenders. The Internet has exacerbated these unbecoming traits by drawing together like-minded followers in chat forums, where the safety of distance and anonymity allow people to say things they would normally be reluctant to say in person.

You’re As Blind as the Company You Keep

Let’s be perfectly frank: when you’re talking about the kind of people who purchase, read, and take seriously the kind of biased infomercial-like tripe found in most popular low-carb diet books, you’re not exactly talking about the most intelligent and reasoning demographic.

Low-carb authors, with their promises of quick easy weight loss and their metabolic advantage theories that apportion blame for obesity not to the dietary and lifestyle indiscretions of the reader but to “evil” carbohydrates, insulin, and the low-fat movement, have successfully pushed yet another common human hot button. That is, the widespread desire to shun responsibility for our flaws and problems and instead place the blame on external forces and influences. While many of us are adult enough to accept responsibility for our self-inflicted woes and tackle them accordingly, many people take solace in the belief that blame for their problems lies elsewhere. After all, this saves them from often uncomfortable soul-searching and introspection, and the unsettling possibility they will need to make fundamental changes in their beliefs and lifestyle. It’s far easier to just blame someone else for one’s problems, a mindset further encouraged by today’s victim-mentality, litigation-mad culture.

The metabolic advantage theory, by proclaiming we can eat more and still lose weight, appeals to the widespread albeit childlike wish to have our cake and eat it too. Telling many low-carbers that their beloved metabolic advantage is non-existent is like taking a favorite toy away from a toddler, a sure-fire method for triggering a Texas-sized tantrum. No matter how much evidence you throw at them and no matter how carefully and painstakingly you state your case, many low-carbers deeply resent being told that judicious nutrition and regular exercise, not carefree gluttony, are the real keys to getting truly lean. In this, they are like the young child who protests loudly at a reality that refuses to conform to his whims and desires. Unlike the young child, however, they cannot cite childhood naiveté as an excuse…

Ooh Baby, Lie To Me

Humans love to be told what they want to hear, a phenomenon known as “confirmation bias”. Receiving information that confirms what we already believe is comforting, reassuring, and self-validating. While people are quick to pay lip service to the importance of “keeping an open mind”, scientific research shows most people preferentially seek out information that is in accordance with their existing beliefs[Hart].

In contrast, information that conflicts with what we want to believe is discomforting and upsetting. During the 2004 US Presidential election, researchers used functional neuroimaging to study the neural responses of thirty committed partisans presented with negative information about both their preferred and opposition candidates[Westen D, 2006]. The purpose of the study, led by Drew Westen, professor of psychology and psychiatry at Emory University, was to observe "how partisan brains reasoned during the polarized 2004 election. The answer: they didn't. When confronted with compelling negative evidence about their candidate, the brains of Democrats and Republicans registered conflict and distress. Whereas the circuits normally activated during dispassionate reasoning appeared to be in a persistently vegetative state when faced with a reasoning task with negative implications for the partisan's candidate, circuits charged with regulating emotion and dealing with conflict lit up our computer screens like the Fourth of July, firing rockets into reason until our partisans had arrived at emotionally comfortable conclusions."[Westen D, 2007]

In other words, the participant's brains had little problem handling negative information about the opposition party candidate, but started ‘freaking out’ when faced with negative information about the candidate from their favored party. Their brains didn’t return to a less frantic state until they had found a way to distort and rationalize the negative information in a way that comfortably co-existed with their belief in the superiority of their favored candidate. These findings go a long way toward explaining why certain myopic segments of the dietary arena – such as low-carb devotees – act in such an irrational and often hostile manner when presented with information that contradicts their treasured dogma.

Conclusion

I suspect the irrational behavior that characterizes certain segments of the dietary arena, including the low-carb arena, is a mix of several factors, including the convergence of several deeply ingrained human traits that may have served protective functions in simpler primitive times, but often lead to self-destructive outcomes in today’s far more complex information-rich society. The tendency to slander and ostracize those from outside groups or with opposing viewpoints is further encouraged by the protection of distance and anonymity garnered by Internet communication.

It’s not unreasonable to suspect, given the findings of the research discussed above, that negative psychological effects of ketogenic low-carb diets may exacerbate this kind of behavior. Whether very low-carbohydrate nutrition does in fact contribute to anti-social behavior is a question only controlled scientific research can definitively answer. However, after reviewing the research, prudence dictates that those with a tendency towards anger, depression, anxiety and especially those with diagnosed behavioural or psychiatric conditions should avoid ketogenic low-carbohydrate diets.

Notes

*For example, when a metabolic ward study by Werner et al found no difference in weight loss between high and low-carb diets, Atkins flippantly dismissed the results, claiming the low-carb diet in that study was too high in carbohydrate to promote ketosis (Dr. Atkin's New Diet Revolution, Avon Books, 2002, p. 70). However, he readily embraced a supportive non-metabolic ward study by Pennington et al that reported greater weight losses on the low-carb diet group, describing the findings as “exciting”. Atkins was evidently so excited he failed to notice that both studies used the same amount of carbohydrates in their low-carbohydrate groups…

Atkins also dismissed the results of a ward study by Pilkington et al, complaining that it “dealt with the 1,000-calorie level, a level at which nearly everyone loses weight”. Yet he had no qualms about embracing the results of an allegedly supportive ward study by Rabast et al - that also employed the 1,000 calorie level! (Dr. Atkin's New Diet Revolution, Avon Books, 2002, p. 68)

Rabast et al claimed that the greater weight loss in their low-carb groups must have been due to that eternally elusive and mythical phenomenon, the “metabolic advantage” - but they never measured body fat composition. To claim that greater fat losses occurred when fat loss was never even measured is most disingenuous, to say the least.

Atkins, by the way, is not the only low-carb promoter to have selectively interpreted the evidence; Dr. Michael Eades, co-author of Protein Power and an ardent promoter of the metabolic advantage theory, eagerly embraces supportive free-living studies (he appears to have very little to say about the abundance of non-supportive ones). He dismisses metabolic ward studies as “rife” with inaccuracies, even when the authors of said studies outlined in detail the meticulous controls maintained over study participants. However, in the same breath and with an apparently straight face, Eades claims the Rabast metabolic ward studies offer “robust” evidence of the metabolic advantage theory[Eades].

Neither Atkins nor Eades appear to have been troubled by the fact that, despite repeated attempts, the Rabast findings have never been replicated by other researchers. Nor were they troubled by the unusually high dropout rates in the larger of Rabast’s two supportive studies for which no explanation was ever given (most ward studies have zero dropout rates thanks to the constant supervision and support)[Rabast, 1979][Rabast, 1981]. And they refused to share with their readers the findings in the Rabast studies that suggest greater lean mass and/or fluid losses were responsible for the greater reported weight loss (despite their untenable belief in the metabolic advantage, Rabast et al admitted in their 1979 paper they were unable to discount greater glycogen loss as a reason for the difference). As evidence for the metabolic advantage theory, the Rabast studies are about as “robust” as a wet paper bag. (Again, if you would like a far more thorough analysis of the Rabast studies than any low-carb author is willing to give you, please refer to chapter 1 of The Fat Loss Bible).

The reality is that, like most other dogmatists, low-carb shills adhere to the following strict but simple criteria when determining the quality of scientific evidence:

Good evidence = that which supports their theories, no matter how shabbily performed and poorly controlled.
Bad evidence = that which contradicts their theories, no matter how professionally conducted and tightly controlled.

References

Lloyd HM, et al. Mood and cognitive performance effects of isocaloric lunches differing in fat and carbohydrate content. Physiology & Behavior, 1994 Jul; 56 (1): 51-57.

Fischer K, et al. Carbohydrate to protein ratio in food and cognitive performance in the morning. Physiology & Behavior, Mar, 2002; 75 (3): 411-423.

Spring B, et al. Psychobiological effects of carbohydrates. Journal of Clinical Psychiatry, 1989; 50 (5, Suppl), 27-33.

Benton D, et al. The delivery rate of dietary carbohydrates affects cognitive performance in both rats and humans. Psychopharmacology, 2003; 166: 86–90.

Wing RR, et al. Cognitive effects of ketogenic weight-reducing diets. International Journal of Obesity, 1995; 19: 811-816.

Rosen JC, et al. Comparison of carbohydrate-containing and carbohydrate-restricted hypocaloric diets in the treatment of obesity: effects on appetite and mood. American Journal of Clinical Nutrition, 1982; 36: 463-469.

Bogardus C, et al. Comparison of carbohydrate-containing and carbohydrate-restricted hypocaloric diets in the treatment of obesity. Endurance and metabolic fuel homeostasis during strenuous exercise. Journal of Clinical Investigation, 1981; 68: 399-404.

Danci et al. Low-carbohydrate weight-loss diets. Effects on cognition and mood. Appetite, 2009; 52 (1): 96-103.
http://ddr.nal.usda.gov/bitstream/10113/23706/1/IND44133744.pdf

Halyburton AK, et al. Low- and high-carbohydrate weight-loss diets have similar effects on mood but not cognitive performance. American Journal of Clinical Nutrition, 2007; 86: 580–587.
http://www.ajcn.org/cgi/content/full/86/3/580

Brinkworth GD, et al. Long-term Effects of a Very Low-Carbohydrate Diet and a Low-Fat Diet on Mood and Cognitive Function. Archives of Internal Medicine, Nov 9, 2009; 169 (20): 1873-1880.

McClernon JF, et al. The Effects of a Low-Carbohydrate Ketogenic Diet and a Low-Fat Diet on Mood, Hunger, and Other Self-Reported Symptoms. Obesity. 2007; 15:182–187.

Galletly C, et al. Psychological benefits of a high-protein, low-carbohydrate diet in obese women with polycystic ovary syndrome—A pilot study. Appetite, 2007; 49: 590-593.

Ehrenreich MJ. A Case of the Re-Emergence of Panic and Anxiety Symptoms After Initiation of a High-Protein, Very Low Carbohydrate Diet. Psychosomatics, March-April 2006; 47: 178-179.
http://psy.psychiatryonline.org/cgi/content/full/47/2/178

Christensen L, Redig C. Effect of meal composition on mood. Behavioral Neuroscience, Apr, 1993; 107 (2): 346-353.

Westen D, et al. Neural bases of motivated reasoning: an FMRI study of emotional constraints on partisan political judgment in the 2004 U.S. Presidential election. Journal of Cognitive Neuroscience, Nov, 2006; 18 (11): 1947-1958.

Westen D. Winning Hearts and Minds: Why Rational Appeals Are Irrational If Your Goal is Winning Elections. Huffington Post, June 19, 2007.
http://www.huffingtonpost.com/drew-westen/winning-hearts-and-minds_b_52893.html

Hart W, et al. Feeling validated versus being correct: a meta-analysis of selective exposure to information. Psychological Bulletin, 2009 Jul; 135 (4): 555-588.

Eades M. "Metabolic efficiency". ProteinPower.com, September 8, 2008. Available online: http://www.proteinpower.com/drmike/metabolism/metabolic-efficiency/

Rabast U, et al. Dietetic treatment of obesity with low and high-carbohydrate diets: comparative studies and clinical results. International Journal of Obesity, 1979; 3 (3): 201-211.

Rabast U, et al. Loss of weight, sodium and water in obese persons consuming a high- or low-carbohydrate diet. Annals of Nutrition & Metabolism, 1981; 25 (6): 341-349.