Jan 03 2011

The Nihilism Diet

In a recent New York Times article, Abigail Zuger takes a crack at the diet wars, and does a reasonable job. There are many points left to be made, however.

The question is, essentially, how to maintain a healthful and desired weight. In broad brushstrokes, the variable are – how many calories people consume, what kind of calories are consumed (the proportion of macronutrients – fat, protein, and carbohydrates) and how much people exercise. These are the (allegedly) controllable variables. The variable we cannot control is our genetics, which largely determines our inherent metabolism and hormonal function.

Different people have different interpretations of the evidence. There are also countless popular diets that don’t even attempt to square with the evidence, but I will largely ignore them for this post.

Zuger spends much of the article discussing the writing of Gary Taubes – a science journalist and author of Good Calories, Bad Calories, and now an updated and streamlined version titled, Why We Get Fat: And What to Do About It. I have not yet read the book, but I have read many of Taubes’ articles and lectures. Zuger summarizes his main points:

We’ve got the whole thing backward, he argues. The overweight are not lazy hogs who eat too much and exercise too little. The thin are not virtuous and disciplined. Rather, all of us are fulfilling a fixed biological mandate, just as growing children are. Our bodies have a nonnegotiable agenda, and our behavior evolves to make that agenda happen, he writes: “Eating in moderation and being physically active (literally, having the energy to exercise) are not evidence of moral rectitude. Rather, they’re the metabolic benefits of a body that’s programmed to remain lean.”

This all sounds nihilistic – our weight is genetically determined, so why bother trying to control your eating and exercise regularly? But Taubes goes on to endorse the low-carb diet. He argues that insulin is the one hormone we can affect, by eating a low-carb diet. Carbohydrates are the villain – the cause of the obesity epidemic.

Taubes knows that his opinions go against the consensus of expert opinion, and he too casually tosses the consensus aside, in my opinion. I do not maintain that the experts are always right, but it’s rare that they are systematically wrong in a field with a lot of evidence. At the very least, I would be very concerned if my read of the evidence was not shared by the experts – I would assume that I was missing something, and not the experts.

Here is what I think Taubes is missing: Interpreting the research is complex – and you have to balance basic science with clinical research. I think Taubes is overemphasizing the basic science (and putting it in the wrong context) and is dismissing the clinical research.

For example, Zuger makes her best point when she writes:

How to account for the fact that in virtually all head-to-head comparisons of various diet plans, the average long-term results have invariably been quite similar — mediocre all around? The party line holds that backsliding is universal. Mr. Taubes makes much of the addictive effect of carbohydrates: once you taste them you never forget them.

Zuger is correct – if low carb dieting were the answer, then the clinical research would show it. What the research shows is that any advantage to low carb diets is minimal (if it exists), and short lived. They are  not the answer to weight control. Zuger then lets Taubes off the hook too easily with his reply that carbs are addictive. This is a massive bit of special pleading, a casual dismissal of a large body of clinical evidence that cuts the heart out of Taubes’ interpretation of the research.

In addition  Taubes and other low-carb enthusiasts get the context of basic science research wrong. First, I agree that genetics largely determine our inherent tendency to maintain a certain weight. Most people who are obese are so because of their genetically determined hormonal function and appetite control. But genetics are not destiny. While our genetics strongly influence our behavior, they do not control it. We have the ability to hierarchically supersede our default behavior. It’s not easy, as the research also indicates, but it is possible.

So far we have not found a safe and effective way to alter our hormones. Low carb diets do not accomplish this (as an aside, they are useful for avoiding and treating diabetes, but don’t seem to help in weight control). There are appetite suppressants, but these are of limited utility. Maybe one day we’ll have an obesity pill, but we don’t now.

So – bottom line, we can’t change our inherent metabolism or appetite. It is also true that if we decrease our caloric intake we will tend to exercise less, and if we exercise we will get more hungry and tend to eat more. Our bodies manage to balance our caloric intake and output fairly well over long periods of time. But if one exercises regularly and limits their caloric intake at the same time that would avoid this automatic compensation.

Another factor that has recently received research attention is that lack of sleep results in hormonal changes that also correlates with obesity, either through increased appetite or decreased physical activity. Getting a good-night’s=sleep is one way to alter our hormonal status in a favorable way.

As evidence that genetics are not destiny is the fact that obesity has been steadily increasing over the last thirty years, and not just in the US but in many industrialized countries. There is a great deal of argument over what, exactly, is causing the increase. It does seem to correlate with an increase in overall caloric consumption. Others, however, point to computers and increased time spent on sedentary activities.

Also (and here is where I think Taubes gets the context wrong) focusing on the hormonal and metabolic differences among people may help explain why person A is overweight and person B is not, but it does not help person A maintain a healthier weight. For that we need to focus on those variables that can be changed. Because the body is a horrifically complex system, even though we can explore and understand many aspects of the system, in order to understand the net effect of making specific changes to one’s behavior, these have to be studied clinically.

The clinical research shows various things. First – there is no significant difference among the various diets based upon macronutrient ratios. Adjusting macronutrients does not seem to have a significant net effect on weight control. Finding a way to control overall caloric intake does work. To be clear, nothing works for most people, since most people fail most attempts at long term weight control. But the variables that do seem to help are utilizing convenient methods for estimating caloric intake. Even just writing down what one eats every day helps. Also, healthy eating should, as much as possible, be the default behavior. Having low calorie healthful snacks around the house, rather than tempting calorie dense snacks, is helpful. Eating at restaurants that publish the caloric content of their meals also makes sense, but I’m not aware of any data on this yet. Meal replacements are helpful, probably because they help estimate caloric intake and help avoid accidentally overeating.

There is recent evidence for a strategy of eating only when their is initial hunger, which correlates with low blood sugar. The idea here is that overall caloric intake will be decreased if one reinforces the pattern of eating only when there is a sensation of hunger.

These types of strategies work for some people, but if we want to have a societal impact on weight then there probably have to be regulations that make default behavior more healthful. We don’t need to take choice away from people – but just make the lower calorie or more healthful choice easier.

Also, there is no question that there are many health benefits to regular exercise. Exercise alone is probably not enough to maintain weight. But if one engages in regular scheduled exercise, that would override any inherent tendency to reduce calorie expenditure, either from reducing caloric intake, or just with age or a sedentary job or lifestyle. It doesn’t matter how much your genetics tell you to exercise, if you stick to a schedule of regular exercise.

I don’t think there is any simple, easy, or universal solution to the problem of weight control.  Reversing the obesity trends will likely take societal changes as well as a focus on the many small things that all help. Perhaps they can add up to a significant effect. I also think that a large part of moving in the right direction is to get away from the distraction of focusing on gimmicks. Ultimately, the low-carb diet is just another weight-loss gimmick. There may be some interesting basic science behind it  – but bottom line, it doesn’t work.

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17 responses so far

17 Responses to “The Nihilism Diet”

  1. Michael Meadonon 03 Jan 2011 at 9:08 am

    Sensible points, Steve.

    Many countries – but especially the US – could use some systematic societal change. The US could stop subsidizing sugar production, for example. Or “nudge” people in the right directions. Pity about all those libertarians.

  2. SARAon 03 Jan 2011 at 1:01 pm

    “I don’t think there is any simple, easy, or universal solution to the problem of weight control.”

    I couldn’t agree more, having struggled with the problem my entire life. At 400lbs I had a gastric bypass.

    But while it certainly worked for getting me to a reasonable weight, I still make bad decisions about food. And 12 years later, I have gained back 50 lbs of my original 230 lbs weight loss. I suppose genetics cannot be outsmarted, but it doesn’t feel genetic when I “know” I am making poor food choices. It feels more like a mental disability.

  3. Calli Arcaleon 03 Jan 2011 at 1:18 pm

    At the very least, I would be very concerned if my read of the evidence was not shared by the experts – I would assume that I was missing something, and not the experts.

    One of Akin’s Laws of Spacecraft Design states “The odds are greatly against you being immensely smarter than everyone else in the field. If your analysis says your terminal velocity is twice the speed of light, you may have invented warp drive, but the chances are a lot better that you’ve screwed up.”

    Low carb diets do not accomplish this (as an aside, they are useful for avoiding and treating diabetes, but don’t seem to help in weight control).

    As my mother-in-law has developed diabetes, I’ve been familiarizing myself with low-carb options for family feasts and one thing that most of them have in common is that they are frequently high in fat instead. Heavy whipping cream has 0 carbs, for instance, but certainly not 0 calories – a cup of cream has 414 calories. Yikes; now I’m looking back at all that rommegrot (cream porridge) I ate at Christmas….

  4. locutusbrgon 03 Jan 2011 at 4:12 pm

    I have a long history of weight issues.
    For the last 3 years I have been successful in weight control. My patients want to know the “trick”. They are always looking for a simple solution. I give them an unwelcome answer, Diet and Exercise. Calories in must be less than calories out. Wise dietary changes and moderation. No special theories/ surgery/ pills/ gimmicks.
    I find two common misconceptions, changing what you eat, and exercising more. Primarily dietary change long term is more complicated than simple changes in macro nutrients. Secondly people vastly underestimate how easily they can out eat any exercises they perform. Suprise, suprise this is supported by research who would have guessed.
    Just no free ride on this one.

  5. tmac57on 03 Jan 2011 at 5:29 pm

    Walking at 3.0 Mph, Level, Moderate Pace, Firm Surface

    224 calories per hour

    Assuming a body weight of: 150 lbs.

    With those assumptions, it would take over 3 hours to burn off the calories in one Big Mac with cheese. Kinda makes you think.

  6. BillyJoe7on 03 Jan 2011 at 8:40 pm

    In progressive Australia, we use kg and cm, but, for our American backwoodspersons, I will convert to lb and inch.

    :)

    My height is 5’5”.

    Before my mid-twenties I never exercised.
    At age 25, I weighed 110lbs.
    I then took up running and ran four marathons in seven years.
    At age 33, I weighed 132lbs!
    Then work overload resulted in exercise falling to zero.
    At age 40, I weighed 155lbs!

    I wondered what would happen if I continued this cycle and began exercising again. Would my weight continue to rise with each cycle?

    (Fortunately it did not. I reduced my workload and took up walking/climbing/running through the local hills. At age 45, I weighed 140lbs, a weight that I have maintained ever since.)

    (BTW, I can eat whatever I damn well please :) )

  7. BillyJoe7on 03 Jan 2011 at 8:48 pm

    Steven Novella:

    “I would be very concerned if my read of the evidence was not shared by the experts – I would assume that I was missing something, and not the experts.”

    Akin’s Laws of Spacecraft Design:
    (Contributed by Calli Arcale)

    “The odds are greatly against you being immensely smarter than everyone else in the field. If your analysis says your terminal velocity is twice the speed of light, you may have invented warp drive, but the chances are a lot better that you’ve screwed up.”

    I love this blog. :)

    Every crank should read this…and if it’s makes no difference, that simply confirms that he is a crank.

  8. Calli Arcaleon 05 Jan 2011 at 11:17 am

    If you liked that, the canonical list of Akins’ Laws can be found at
    http://spacecraft.ssl.umd.edu/akins_laws.html

    Many are far more applicable to engineering, some very specifically aerospace engineering, and some are actively misleading when it comes to science. (Engineering is not science, after all, which is not a bad thing; it simply has different goals.) But here are two others which may be applicable when discussing alt-med:

    Not having all the information you need is never a satisfactory excuse for not starting the analysis.

    The previous people who did a similar analysis did not have a direct pipeline to the wisdom of the ages. There is therefore no reason to believe their analysis over yours. There is especially no reason to present their analysis as yours.

  9. SimonWon 06 Jan 2011 at 12:34 pm

    How to combine the benefits of waiting for initial hunger, and dining together…. Do I have to wait till everyone in the family is hungry?

    I have my thyroid hormone levels under manual control.

    This is a lot less useful than most people think for weight regulation, as I only lost substantive weight when massively thyrotoxic (i.e. I lost weight quickly only when the condition was life threatening). The hypothyroid retain more fluid, so lose that “weight” with treatment, which I think explains the popular association of fat with hypothyroidism.

    But does this open up my diet options any? Regulation here is complex, the hyperthyroid crave carbohydrates (the process by which this preference is regulated is reasonably well understood), which is presumably part of why I didn’t lose much weight (I ate a LOT of biscuits when hyperthyroid).

  10. Robbon 07 Jan 2011 at 7:55 pm

    I appreciate your logic and arguments in nearly everything you write, but there’s one issue about which you write, where I don’t follow your logic.

    I don’t follow your logic for your dismissal of low-carb diets:

    “Ultimately, the low-carb diet is just another weight-loss gimmick. There may be some interesting basic science behind it – but bottom line, it doesn’t work.”

    This was your conclusion for the piece, which was actually about a different topic. I didn’t really see support for the “it doesn’t work” conclusion. Would you mind laying it out for us?

    I’ve also heard you many times on SGU say, “it’s all about calories in and calories out.” However, that seems to be inaccurate, although true. What I mean is, by calories “in”, it is *not* how many calories one orally consumes, but rather, how many calories the body absorbs. You haven’t addressed this difference in meaning. I believe this issue (calories absorbed) can be key for some diets, such as Atkins. The time dimension is yet another factor that ads complexity which you’ve glossed over. It also lends support to other aspects of Atkins, such as attention to the “glycemic index” of foods.

    I’m genuinely interested to hear your comments on these issues.
    Thanks.

  11. Charleson 12 Feb 2011 at 4:11 pm

    Hmmm,
    I think that you are too quick to dismiss Taubes arguments. Especially since it seems you are dismissing his opinion based on a synopsized version of it from the NYT. I read his “Good Calories Bad Calories” three years ago and thought it was credible enough to try low carbs for myself and had some success. Note I also convinced my girlfriend to try it and she did not have success. So I would not say that low carb will be universally successful.. Neither apparently is straight low calorie dieting even with exercise as also experienced by my girlfriend.

    And you seem to gloss over the articles you cite in your supporting links, for example, at (http://www.ncbi.nlm.nih.gov/pubmed/16476868)
    “CONCLUSIONS: Low-carbohydrate, non-energy-restricted diets appear to be at least as effective as low-fat, energy-restricted diets in inducing weight loss for up to 1 year. However…” and they go on with the caveat that low carb seems to be less healthy from the cholesterol perspective.

    Finally, I would say also that Taubes, at least in his first book, talks in detail about the orthodoxy of scientists with regard to public health issues and difference between what is good guidance statistically for the public at large vs what is good guidance for individuals. I think that history has shown us (Gallileo, Newton, Einstein anybody) that consensus scientific opinion is not *always* correct opinion.
    Regards,

  12. Steven Novellaon 13 Feb 2011 at 9:34 am

    Charles – the evidence is the evidence, regardless how much time someone takes to discuss it. The fact is that the clinical research does not support an advantage for low-carb diets. You can make all the arguments you want about why it should work (and there are just as many for why it shouldn’t) – but we have clinical data that shows that it doesn’t. Taubes simply dismisses this as not studying low enough carb diets, but this is not true. It is also special pleading.

    I don’t argue that consensus is always correct – but it is correct more often than minority opinions, especially from non-scientists. What I object to is dismissing the consensus opinion in the way that he does. The consensus is actually based on research.

    Where I think Taubes goes wrong is that he does not know how to balance the various different types of evidence that seem to point to different answers. He puts too much weight on basic science, and dismisses the clinical evidence. He underestimates the difficulty in extrapolating from basic science to ultimate effects.

    Meanwhile, the clinical research is fairly mature and is also fairly consistent – there is no real long-term advantage to low-carb diets.

    In the specific article you cite – the conclusions support the above. Low carb diets were “as effective” – not better. All diets are basically as effective as all other diets, and they all work by reducing calories (whether or not they are controlled for). There is copious evidence to show that all diets ultimately work by reducing caloric intake.

  13. morris39on 20 Feb 2011 at 12:53 am

    Steven
    I believe you are placing too much uncritical reliance on the medical research and clinical studies and so perhaps falling into the trap you oppose. I should state that in general I like and agree with your point of view; in general only because I have not read all the posts.
    I have done an experiment avoiding certain foods (grains & legumes) and replacing them with fats. I have experienced a number of definite, small but significant health gains. An experiment of one, with reliable observations but basically unexplained causes. I did not set out to do this experiment but in fact gradually went from the conventionally recommended diet to eating yet more plant protein, less fat and meat etc with clearly unfavourable results in a short time (3 months). The results were plain to see, deterioration of teeth and gums. I was otherwise healthy. This preamble has a point; I was healthy and normal weight unlike most proponents of the so-called low carb diets who (judging by blog posts) were either repeatedly unsuccessful in losing weight or had refractive chronic diseases. That group seems to be a population subset that is not metabolically representative. There are superficial reasons (in addition to medical advice) to be sceptical of the high density diet: most advocates profit from supplements etc, those that do not cherry pick their data shamelessly, many adherents come from a desperate backgrounds, and there are no studies supporting the diet. The question I had to answer was whether there is any evidence which suggests that it may be safe to try the diet for a short time, say 3 months, which was about the time that it took the negative results to appear. I found historical and anthropological data sufficiently plausible to attempt the test. Once I saw beneficial results I was not willing to simply abandon the diet, but the problem still remained of the strong medical avdice against it. The next question to answer was just how strong was the conventional science. The answer is: not very strong and so it could be mistaken to some degree. I fully recognize the logical fallacy of pointing out a weakness in an argument and then claiming that the opposite is true. If weakness is in fact plausible then an experiment, no matter how anecdotal, cay carry more weight than the collective wisdom. So what are the weaknesses?
    Medical research has a reputation for very poor reliability in general. See Why Most Published Research Findings Are False by John Ioannidis, 2005 available on PloS. This paper to my knowledge has been well received and not challenged. If you do not agree with that statement you may consider taking the paper on as a future topic.
    Observational human studies are useful for generating biologically plausible hypotheses but are difficult to do. The studies which underpin the conventional thinking are 50-60 yo and were not done rigorously. There is little that is biologically credible as well. There is little incentive to repeat or challenge these studies. Nutrition offer little future in academic or research careers and no financial support from drug companies. This field is a forgotten back corner left to dieticians. Nutritional advice is usually offered by GPs and bureaucrats but GPs get almost no training in nutrition or evolution, so are hardly experts. Metabolism and nutrition are extremely complex and difficult and open to divergent views. New data increasingly points to ever widening complexity particularly in genetics and immunology.
    So that is my reason for not accepting conventional wisdom uncritically and continuing the experiment, which is now 8 months old. The diet regime is not demanding, the food is tasty, I do not see it as a “diet” and at this point I see no reason to discontinue it. Personal conventional medical tests do not indicate negative trends. Of course the results could be temporary or transient and if so I would have to adjust. Of course my experiment results do not apply to entire populations or maybe even other people but that is not my point. That’s the post. Sorry for the length.
    Morris

  14. morris39on 25 Feb 2011 at 11:55 pm

    Steven
    I posted above comments after a cursory browse of the site. I would really appreciate a response from you. I now see that the tone of my comments probably do not fit the blog, so with apologies I will rephrase my point which is more a question rather than a challenge.
    What I am not looking for:
    Debate or advocacy of/forvarious diets
    Medical advice
    Arguments
    My question to you (given details in previous post) is purely academic. Grant that my observations are accurate, albeit on a short time scale, how do you rationally balance the observed results against conventional dietary advice? I believe that this question reduces to the ratio of degree of perceived certainty in each. If I express a high degree of certainty in my observations (subject to possible revisions after longer observation) can you say that conventional diet advice should be accepted regardless? If so, does such a view qualify as being sceptical?
    Thank you for time,

  15. frankjspencejron 05 Mar 2011 at 3:13 pm

    Below is the reference Steven was seeking regarding dietary trends (low fat vs low carb. It is clear that most of the excess calories people have consumed in the last 40 years vs prior have been carbs.

    http://www.cdc.gov/mmwr/preview/mmwrhtml/mm5304a3.htm

    Excerpt:
    During 1971–2000, a statistically significant increase in average energy intake occurred… For men [and women] the percentage of kcals from carbohydrate increased between 1971–1974 and 1999—2000.
    The percentage of kcals from total fat decreased .. for men and for women. In addition, the percentage of kcals from saturated fat decreased for men and for women. A slight decrease was observed in the percentage of kcals from protein,
    The decrease in the percentage of kcals from fat during 1971–1991 is attributed to an increase in total kcals consumed; absolute fat intake in grams increased. USDA food consumption survey data from 1989–1991 and 1994–1996 indicated that the increased energy intake was caused primarily by higher carbohydrate intake (6). Data from NHANES for 1971–2000 indicate similar trends. The increase in energy intake is attributable primarily to an increase in carbohydrate intake…Total fat intake in grams increased among women by 6.5 g (p<0.01) and decreased among men by 5.3 g (p<0.01).

    The latest national dietary data available indicate that the previously reported increase in energy intake has continued, reflecting primarily increased carbohydrate intake.

  16. JimOldguyon 19 Mar 2011 at 2:07 am

    “Here is what I think Taubes is missing: Interpreting the research is complex – and you have to balance basic science with clinical research. I think Taubes is overemphasizing the basic science (and putting it in the wrong context) and is dismissing the clinical research.”

    Absent actually reading what Taubes actually says, characterizing his approach to the clinical research can be a bit misleading…. there is a “straw-man” risk.

    In fact, Taubes’ original book (Good Calories, Bad Calories) does describe much of the relevant research in excruciating detail, and while he does dismiss much of that research, he does so for what he regards as cause (and explains the reasons).

    In my opinion, one cannot get the real flavor of his (earlier, longer) book just by listening to his lecture; the lecture omits a lot. To understand why he says what he says, I’m afraid you actually have to read the (older) book. He may be wrong, but he is worth a serious read.

  17. elion 06 Mar 2012 at 4:47 am

    Hi, Steven
    I think you are shortchanging GCBC, it in my eyes has two parts, the first and the most important is an extremely detailed discussion and review of the literature and all the major trials, which convincingly shows that nutrition science community is not a functioning scientific community in any reasonable sense of the term, as Taubes writes:
    “The institutionalized vigilance, “this unending exchange of critical judgment,” is nowhere to be found in the study of nutrition, chronic disease, and obesity, and it hasn’t been for decades. For this reason, it is difficult to use the term “scientist” to describe those individuals who work in these disciplines, and, indeed, I have actively avoided doing so in this book.”
    The second part is the “carbohydrate hypothesis” which is both reasonable and compelling and presented by Taubes as a hypothesis to be tested, he also suggest various protocols how to test it, more so in WWGF, he writes: “What’s needed now are randomized trials that test the carbohydrate hypothesis as well as the conventional wisdom” ….” But it’s hard to imagine that this controversy will go away if we don’t do them(the trials), that we won’t be arguing about the detrimental role of fats and carbohydrates in the diet twenty years from now”.
    It is very often stated by you and on SGU that “scientific consensus” and “the experts” should be the guiding principle, It is in my eyes correct, but there are caveats, it first need be convincingly shown that the experts are a part of a functioning scientific community, otherwise their consensus and expertise is the same as the expertise and consensus of any other CAM. I think Taubes met, and exceeded the burden of proof on this point, I view GCBC as the best skeptical book I ever read.
    It is only an extreme minority that doubts the science behind vaccines or nuclear physics for example, is it because all are familiar with the science? And trust the scientists? I think it is due to the visible results of those disciplines, nutrition science doesn’t have any results, since the beginning of nutrition science meddling in public health – there was a catastrophic turn for the worse. Both from personal experience (people become hysteric about even seeing fat in their food nowadays – after years of low-fat messages, this was very different when I was young, and people were thin) and NHANES surveys it is clear that the public and industry took to the “low-fat” recommendation – this is an association, but at the very least, it has to be acknowledged, that this might be a big part of the problem. In addition there are no real cures for obesity developed, nor there is any real understanding of the underlying causes after decades of “research”– hence I think it is hard to convince me I should defer to the experts – because there is no compelling reason to think they are *real* experts.

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