Recently, it seems there has been a backlash against medicine and the current knowledge of the relationship between diet, weight and overall health. I don't actually believe this is directly the fault of scientists or doctors, who react to the trashy mainstream reporting of science with little more than the occasional raised eyebrow. However, many people in response to all these silly health pronouncements, which seemingly come from on high but really are from press coverage of often minor reports in the medical literature, have lost their trust in what science has to offer as a solution to what Michael Pollan refers to as "the Omnivore's Dilemma". That is, what should we be eating?
The result of this confusion is a mixture of distrust, cynicism, and receptivity to crankery and lies about diet. After all, if science ostensibly can't keep their message straight, who knows what to believe?
The fact is, science knows many things about the relationship between diet, obesity, and health with great confidence and it hasn't changed nearly so much as the popular press would have you believe. The failure to state clear messages about nutrition is a reflection on the haphazard way in which nutritional health is reported, the often confusing nature of epidemiologic science, and the various parties that are interested in cashing in the confusion by promoting their own nonsensical ideas about diet.
Take, for example, Sandy Szwarc. Sandy doesn't believe obesity or any food choices are actually bad for you. To help spread this nonsense she dismisses valid sources of information like WebMD (which has quite good information) based on the rather silly conspiracy that they have designed their entire website and health enterprise around misleading people into using their products - especially weight-loss products. Because, you know, it's impossible for a corporation to offer free health advice as a public service without conspiring to grab you buy the ankles and shake the money from your pockets. But it doesn't end there. We see rest of the standard denialist tactics of course!
Case in point, in a recent article she makes the astonishing assertion that her mortal enemy - bariatric or gastric-bypass surgeons - have admitted that obesity makes you healthier!
Today brought another unbelievable example of ad-hoc reasoning, as well as a remarkable admission that the war on obesity is without scientific merit. It appeared in a paper published in the journal for the American Society for Bariatric Surgery (now calling itself the American Society for Metabolic and Bariatric Surgery), which is edited by the Society's president, Dr. Harvey Sugerman, M.D. FACS.
The article, "Do current body mass index criteria for obesity surgery reflect cardiovascular risk?" was "work presented at the 2005 American Society for Bariatric Surgery Meeting in poster form." The authors, led by Edward H. Livingston M.D. at the University of Texas Southwestern School of Medicine, reported that the conventional risk factors for cardiovascular disease "decreased with increasing degrees of obesity."
Yes, you read that correctly, decreased.
"Therefore," the authors argued ...
"the criteria for obesity surgery should be changed to lower BMIs than are currently used."
Now, boys and girls, what is the very first thing you do when a suspected denialist feeds you some nonsense in quotes? Check the source! Always, always, always, check the source. Let's expand those six words that Sandy lifted out of the abstract and see what else the authors had to say:
Obesity is an underlying cause of the development of cardiovascular disease (CVD). Obesity itself does not result in CVD, rather, it acts through intermediate-risk factors. [ed - note this, it becomes important later] Most, but not all, studies examining the obesity-CVD relationship have found them to be correlated. We hypothesized that the inconsistencies among the studies of the obesity-cardiovascular relationship were attributable to an irregular relationship between obesity and the presence of risk factors for CVD....
Of the conventional CVD risk factors, blood pressure, serum glucose, and waist circumference increased linearly with adiposity. The reverse was observed for high-density lipoprotein. Insulin, C-peptide, apolipoprotein B, non-high-density lipoprotein cholesterol, low-density lipoprotein, and serum triglycerides all peaked in the body mass index range of 30-40 kg/m2 and then decreased with increasing degrees of obesity. [ed - this is all that Sandy took out of this abstract!]
Conclusion
Cardiovascular risk factors are markedly increased for many individuals with a body mass index >30 kg/m2. Massively obese individuals might have better CVD risk profiles than less obese individuals. The discrepancy is related, in part, to body conformation. The criteria for obesity surgery should be changed to lower BMIs than are currently used if patients have risk factors for CVD.
Sandy goes on to suggest that the conclusions were a "twist of logic" etc. Well, yeah, if you take 6 words of an abstract out of context, ignore that risk factors peaked with BMIs between 30 and 40, and take the interesting finding that some of these risk factors (but by no means all) are decreased in the > 40 group completely out of context, yes you could possibly find a twist of logic. There is no other way to describe her cherry-picking of this article as anything but gross mendacity.
Sandy makes a lot of hay out of articles which show, as the authors alluded in this abstract, a weaker link between obesity and mortality/cardiovascular disease. Her secret is of course to ignore that first bolded sentence from this article, which is absolutely true. I'll quote it again, "Obesity itself does not result in CVD, rather, it acts through intermediate-risk factors". This is absolutely right, a very clear and concise description of the problem. Obesity itself does not cause death! Obesity causes high blood pressure, diabetes and insulin resistance. There are a host of other problems it causes or worsens, but most importantly, diabetes and insulin resistance which then cause atherosclerosis. Diabetes also does not result directly in mortality - few people die of diabetic ketoacidosis or hypoglycemic shock - however, 80% of people with diabetes will die of cardiovascular disease.
So what happens when you study an obese population for mortality or cardiovascular disease risk? It becomes difficult - especially in more recent studies - to identify the obesity-disease relationship. Why? Because when you do a study or a survey on obesity, you don't force the obese group to stop taking their BP meds, their cholesterol meds, their diabetes meds etc., while you are studying them to see if obesity is risky. What we've learned since the first major national study of health (NHANES I) is that when risk factors like blood pressure, cholesterol and diabetes are controlled, the risk of death decreases dramatically from being overweight. See this figure from the most recent NHANES trial:
As you can see, we're getting better at keeping people alive generally. The data from NHANES I and II weren't wrong, in the last 20 years there has been a great emphasis put on treating the risk factors of the obese rather than just constantly yammering at them to lose weight. Sandy is correct, it is very difficult to make people lose weight, and attempts to design a scientificaly proven effective weight loss trial have been largely futile. That doesn't mean it's a bad idea to lose weight, that it is impossible to lose weight, or that people shouldn't be encouraged to do so. You wouldn't discourage a smoker from quitting just because it's difficult to make people quit smoking. Some will, and they will benefit from the change.
The other issue is that she keeps on alleging a protective effect from obesity because all those skinny people in trials of heart medications keep on dying faster. For someone who complains about correlation not being causation, it's funny that she suggests obesity is therefore protective.
If these bariatric researchers are concerned about heart disease deaths, they only have to look at the body of evidence showing a protective effect of obesity among heart patients, even those with the highest rates of diabetes, high cholesterol and high blood pressure. The huge randomized INVEST trial of people with heart disease and hypertension, for example, demonstrated that the obese, BMIs 30 -
As has been made clear, again and again, obesity doesn't get you, it's the secondary effects. What happens when, like in these trials like INVEST, the blood pressure, diabetes, and cholesterol are controlled with drugs (remember - they have higher rates but in a trial these conditions are being managed with drugs!)? Well, they're going to live just as long! And in cohorts of older folks, skinnyness is a bad sign. What happens to old folks before they die? They shrink. You think I'm kidding, work in a nursing home. Weight loss and skinniness in the elderly is an indication of impending doom, not good health. A higher BMI group, therefore, selects for a group that is less likely to have chronic illness or is experiencing wasting and cachexia. It selects for a healthier group in the elderly! A similar obesity protective effect is often shown with smokers and is just as specious.
Further, I can't figure out why she cites the INVEST trial in this particular instance. INVEST was a huge trial and has resulted in multiple publications based on post-hoc analysis of its data. I'm sure one of the analyses provided some result for her to cherry-pick and read out of context. It's bad for Sandy, but the predominant emphasis of some of these analyses was that control of diabetes (with higher risk of DMII in obese cohorts) was one of the most important factors in controlling cardiovascular disease. And how do we avoid diabetes? Maintaining a reasonable weight!
She ends with a little conspiracy suggestion in this article too - I love it! Such denialism.
*** Readers may not know that the University of Texas Southwestern Medical Center, where a lot of recent bariatric and weight loss promotional papers have been originating, was awarded a $22 million grant this past September for its Task Force for Obesity Research.
What pisses me off most about Sandy is that some people think that she's a real skeptic. Despite the illusions of persecution, the David and Goliath complex, the cherry-picking, the alleged conspiracies, not to mention the prominent link to Steve Milloy's Junkscience from her homepage, they can't figure out that this is garden variety denialism. She gets regularly featured in our very own Skeptic's Circle, and shouldn't we be the ones best at smelling a rat? Clearly not. Part of the problem is she doesn't always submit the really cranky stuff on obesity to the circle, and even a broken clock is right twice a day. The other problem is the hosts are rarely able to investigate each blog that sends a nomination.
All the same, I'm afraid I'm going to have to put my foot down and say, if she is linked from a future Skeptic's Circle, I'm not going to link it. Don't lend this person any more credibility than she deserves by calling her a skeptic, unless you want to also include HIV/AIDS skeptics, Global Warming Skeptics, and all the other skeptic wannabe's out there.
Finally, as far as the original question of what should we be eating, the answer, I think is pretty straightfoward and hasn't changed much. You should eat a nutritionally-balanced diet, low in fat, and your caloric intake should not exceed your caloric output. I like Michael Pollan's advice. Roughly, eat what your parents did, not too much (take in consideration the change in physical activity), and avoid fads. Ultimately, the worst problem with all the fad diets, stupid reporting, and nonsense from people like Sandy who say exercise causes weight gain, is that they're at least tangentially suggesting the human body violates the laws of physics. While the efficiency of metabolism might vary slightly between individuals, it's not going to vary by a huge amount, and people are always exaggerating the amount they excercise versus the amount they eat to justify their "slow metabolism" (read: violation of fundamental laws of physics). If you eat more than your baseline metabolic requirement plus your daily caloric output, you will gain weight. If you eat less than your baseline metabolic requirements plus your daily caloric output, you will lose weight. Anything else, and you're suggesting energy is being created or destroyed, and I just don't have time for such nonsense.
P.S. I recently acquired Gary Taub's new book attacking nutritional epidemiology (not a difficult task), and plan to evaluate it for crankery. While I know I disagree with Taub based on what I've heard him say so far, I haven't heard him use the tactics. Generally, nitpicking is his major fault, but that in itself isn't enough to justify reproach.
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A very nice analysis.
One thing I hear every day is "Doc, I don't eat anything. How come I keep gaining weight?" The answer is easy---you're taking in more than you're putting out. Input, output, or both have to change. They never believe it.
Other problems related to severe obesity include heart failure, pulmonary hypertension, obesity-hypoventilation syndrome, and inability to fit into medical testing equipment.
For more obesity denialism, check out Denyse O'Leary's rant here: http://www.salvomag.com/new/articles/salvo3/3oleary.php
For those who don't remember Denyse, she's a fundamentalist creationist associated with Bill Dembski, who writes books about the pseudo-scientific search for the soul.
Turns out she's also an all-purpose crank.
Ugg, it's the same crankery as always about diet.
Yes, people selling diets are totally full of shit. Yes, most people don't lose weight. Yes, in studies (usually with obesity as a secondary focus) obesity doesn't appear to affect mortality.
However, as we've said time and again, it's about primary vs secondary prevention. Obesity is unhealthy but the negative effects can be largely managed with good medical care. The problem? Not everyone gets good medical care or can afford it, the drugs are expensive, not everyone is compliant, etc. It's better to just avoid the high blood pressure, diabetes etc in the first place by not gaining too much weight. It is questionable whether it's worth any great effort to convince the overweight to lose weight as a physician. It is far more important to control the morbidities of obesity rather than trying to convince the overweight to constantly torture themselves with diets.
While I agree with your general sentiment about crankery, and even about a 'general idea' of what we should eat, I think it's a lot more dicey than you let on. Not too long ago the whole food industry switched wholesale from palm oil and lard to partially hydrogenated vegetable oils in the name of health. We were told to avoid salt and eggs and butter. Now we find out that PHVO is toxic, and recent studies have indicated that regular egg consumption doesn't seem to increase cholesterol to any significant degree, and sodium in and of itself doesn't seem to increase blood pressure in the long run. In fact, as nearly as I can tell, someone who eats butter, eggs, and salt, and exercises well and daily, has a much better health prospect than someone who eats 'right' and is a couch potato. I started working out daily, lost a TINY amount of weight, but my blood pressure and cholesterol dropped like stones.
The egg thing is a good example of science progressing over multiple decades.
Basically back in the 40s-50s science didn't really know WHY people had heart attacks. They initiated a massive study of a group of people and followed them over their whole lives. This study discovered a correlation with high blood pressure and high cholesterol with heart disease. Of course this is when people started avoiding cholesterol(eggs for one thing). It wasn't until later that it was discovered that cholesterol comes in two forms, one good and one bad(yay, eggs are back). Clearly the first study showing that eating high cholesterol foods is bad for you wasn't wrong, they just didn't have the complete picture yet.
@Boosterz: Sure, I get that, but my point was that we learn 'new stuff' about foods every day, and to a lay person that can be confusing. Think of the emphasis that was placed on cutting eggs out of your diet. I know this wasn't the fault of 'dietary science' as a class, but a combination of expedient media and the lack of understanding of the complexities of lipids. However, MANY doctors are still advising their patients to avoid eggs, because "we know" they're bad for your heart. The lack of consistent information across the medical profession contributes to the confusion that the denialists in question exploit for their own purposes.
Further complicating the issue are things like recent studies surrounding low-carb diets. A couple recently have shown that low carb diets are more effective at promoting weight loss, and despite all the 'conventional predictions' to the contrary, have typically shown no significant effect on cholesterol levels - and have often exhibited a salutary effect on "good" cholesterol. I know, that's not the WHOLE story - some say that people on low carb diets self-limit their intake of foods, and most people will lose weight if they eliminate processed sugars, processed grains, and simple starches from their diets, but it still adds to the confusion of the lay person - or the self-delusional - and allows the denialists more talking points.
One also has to realize that the average obese person isn't the 400 lb Twinky-gobbling, Whopper eating, SuperSized diet-coke behemoth that the media shows us when talking about obesity. There are millions of people with an extra twenty to forty lbs that live essentially the same lifestyle as their cube-dwelling peers. We can SEE that there are people who pay no attention to diet, no attention to exercise, and are still 'ideal weight' examples. Who eat anything they want and gain no visible weight. In addition, it's unlikely that such a person will sign up to participate in a study of obesity.
So while it's ABSOLUTELY true that consuming less energy than you exert will result in weight loss, it's NOT true that those setpoints or quantities are identical across the population. It's almost certain, in fact, that they aren't.
These types of things always remind me of the Bloom County comic that has Opus pondering which diet fad he should try and ends with Milo chasing him around thwacking him with a stick yelling "eat right and exercise!" Heh, good stuff.
"inability to fit into medical testing equipment"
I worked in a CT scan department for a couple years and this came up at least once a week. Even more frequent was people who could, in theory, fit in the machine but were too heavy for the table.
In our ER not so long ago they brought in a man 450+ lbs; the ambulance atts and ER nurse put the transport gurney next to the ER one and the attending looked around and said, "Gentlemen...I'm open to suggestions."
Needless to say they were bringing him in due to shortness of breath. And yes, hx was + for diabetes, heart disease, yada, yada, yada.
But no one could even figure out how to begin examining him to care for him and treat him. I'm sure it's all the ER and modern medicine's fault if he's ill, right? He shouldn't just be supported and worked with to train him to eat better, exercise, take his meds, and so on.
What puzzles me is people's reported weight. I'm overweight by a good amount (exercising daily and trying to 'eat right', making slow progress) but I know how much I weigh, every day. When such discussions come up, people around me start volunteering their own weight. I'm constantly amazed at the number of people who talk about their weight with numbers that seem ridiculously low - a fellow that's six feet two inches tall and wears pants with a 55" waist probably outweighs me, but he claims to weigh 250 while I weight 275 (at 6 feet tall with a 42" waist). A lady that's five foot five and nearly as wide as she is tall tells me she weights 200 lbs; I know a couple of women who tip the scale at 200, and both are MUCH smaller than she is. Is it anomalous that I would report my weight accurately, or am I that much more physically dense than others? The prior seems more likely.
This seems off topic, but what I'm getting at is this: If we can't even be honest with ourselves, we give denialists a lot of 'wiggle room' to manipulate us. If we're so dedicated to self delusion that we'll do it ourselves, we'll embrace someone that says what we want to hear without regard to the validity of their assertions.
@Steve,
If it were just a number on a scale, it would be easy to say that number out loud. It isn't just a number; it carries a bunch of social crap along with it. Fat hate is real.
It's funny, actually. When being fat meant you were rich, everyone wanted to be fat and it meant you were healthy (from a social standpoint, not a scientific one). But now, only the poor are fat and everyone wants to be thin, with fat being one step above radioactive as a social stigma.
I am not Anonymous. I am Christina.
"Fat hate is real."
Well, yes, it is. But that doesn't mean it's good to lie about your weight or not know what it is. I think those who hate fat people aren't going to care if someone says they only weight 200 pounds when they weight 300, but being honest with yourself is a good way to motivate yourself to lose it. One of the reasons I lost (and am still losing) weight is because I started weighing myself.
Working in a hospital helped too, seeing the results of damaging lifestyles is a real eye-opener. It also helped me quit smoking. There is nothing like having a cancer patient say to you through an artificial voice box "(bzzt) do you want to end up like this? (bzzt)".
"I know a couple of women who tip the scale at 200"
This woman tips the scales at close to 210. I know I need to lose weight, and lying about what I weigh won't help in that. (Though at 5' 11" I'm not quite as fat as that sounds at first. This excuse is my smaller version of a lie about my weight.)
Mistreatment of the obese is a serious problem and much of the reaction of the fat acceptance movement to medical science is in response to abuse they receive at the hands of people, doctors and the media.
One of their great accomplishments has been an increased sensitivity in most (but not all) doctors to the fact that obese patients must be treated. First and foremost. That seems obvious, but doctors were often making weight the only issue and not treating their BP, diabetes etc. This is not only cruel but scientifically unjustified. You can't make people lose weight very easily, and in the meantime you can do a great deal of good by treating the co-morbidities.
Always treat the co-morbidities. That is the lesson here.
The problem is, and why I'll attack the fat acceptance movement, is in their anger over being singled out in so many ways, they attack science itself or propose pseudoscientific explanations for their weight, or diets, etc. This is not ok. I'm completely sympathetic, as I am to several denialist motives. They're not all bigots, sometimes they're people with excellent motives who are using scummy tactics. This is just such a case. In light of their frequently unfair treatment they react to a perception that their "sin of sloth" is being medicalized to further persecute them. They're wrong, it's conspiratorial and nuts and besides the point. But I understand.
"doctors were often making weight the only issue and not treating their BP, diabetes etc."
(shudder)
Appalling, I don't know how it could be done in good conscience. I have to say I never saw it when I was working in health care, but the only time I saw patients was when they were getting treated for things other than obesity (disclosure, I did transport, I never treated a patient). Although I must say it doesn't surprise me, I have met some truly cold, hidebound and even stupid doctors.
Good post. I've been waiting for someone to debunk that blog ever since a friend sent me the link a few months ago. It's truly awful.
I also look forward to a post on Taubes. I read the book. It honestly doesn't go too far into crank territory, but some of the things he says, particularly about exercise, are clearly wrong.
But it's also clear that weight loss is not just about calorie input-output equations, that food is more than just the sum of its calories, and the quality of what you eat really does matter.
You know, it might not be a bad idea to send along a link to this article whenever you're submitting to a Skeptic's Circle. Not everyone is going to know beforehand that Sandy is a crank, especially if she sends reasonable articles (as she did with me, and I fell for it).
You know, I have to say the current state of obesity research confuses the heck out of me. On one hand I disagree with "denialists" but I also have some serious issues with how modern medicine approaches the concept of obesity. I may not be a doctor, but I am nearing the completion of my doctorate in the biological sciences, and I feel fairly comfortable reading the primary literature.
I must say I'm pretty sympathetic to the FA movements questioning of many research studies. Are you suggesting that every medical study in the history of science hasn't been influenced by their funding sources, really? Sure conspiracy studies may be tiresome, but to straight out deny that phenomenon seems a little baby-and-bath water to me. I mean, Mark, at the end of the post you trot out the great Entropy argument, and from my understanding, there are many factors that can affect metabolic rate, and that changes in diet can influence it. For all the talk in physiology about stasis, suddenly when it comes to food consumption, are metabolism is a fixed constant? Isn't it a little more complicated than calories in vs. calories expended?
Maybe it is a personal issue, since I have been active all my life: rower, skiier, biker, swimmer, mountain climber, yoga nut and I have an extremely healthy diet of veggies and lean protein (in fact I have celiac's so NO there are no donuts/McDonalds, etc. in my life) yet I have had a BMI that has hovered in the overweight/obese category since I was a teenager. Despite that BMI I have what my doctor says is low BP, low cholestrol, etc, etc. Many in my family are also in this BMI category, yet there is not a single diabetic or heart disease sufferer in the bunch, and no that is not because they are on medication to prevent it.
So what are we supposed to do with current medical advice for obese people? I have seen members of my family put themselves through increasingly more extreme diets and risk their health in an effort to lose weight and become what they are being told by the medical community is more healthy than their current weight.
What many FA advocates are arguing is that it is not entirely obesity that leads to increased risk of CVD and other diseases, but inactivity. Is there some reason that you don't mention the recent (Dec, 200&7) Sui, et al. study in JAMA?
So I'm not necessarily hitching my wagon to Sandy's analysis, and in fact object to many of her assessments. I do think you do a good job here of dissecting her take on this particular study, but to take the other position and toe the line about obesity is bad, point-blank seems, well a little more dogmatic than I would expect.
Seriously,
I appreciate legitimate concerns such as yours. I'll tell you what I believe is reflected by the data.
1. At young ages it is better to be normal weight than it is to be obese. CVD, which is the main concern, is a slow process requiring decades to really develop. The longer you stay thin the better, until about age 50, then for most patients they say screw it, you can gain some weight, get some middle age spread and be happy for all we care. You're going on BP and cholesterol meds for the most part anyway.
2. At older ages being underweight is a bad sign, it can reflect chronic disease or illness. It's a fact that throughout adult life people gain on average a pound a year until about age 65, then they lose a pound a year until they croak.
3. The Sui study, notice, studied these older adults and found that the most important factor was exercise, which I think is quite likely true. But also remember, they didn't take these adults off their cholesterol meds, their BP meds, their diabetes meds etc., in order to independently test adiposity and the fact is that if you control the secondary effects of obesity - insulin resistance, higher BP, hypercholesterolemia etc - you nullify its effect on mortality. You have to take modern studies with intense control of risk factors as multi-variate studies, and adiposity itself does not directly cause disease. It causes other problems which cause CVD. Also note that exercise in this population is not an independent variable either. People who are sick, can't exercise. The loss of exercise capacity can be a sign of chronic illness, people who are wealthier can exercise more and I'm not sure it's as perfect an indicator as one would like. Epidemiologic studies are complicated, to say the least.
4. Obesity because of these things is not an absolute indicator of your mortality. Even without treatment there are always people that are exceptions. Take for instance Winston Churchill. He died at >90 years, was round as a tire, smoked, dranked, and in general was not a good boy. What we're talking about here is risk, not destiny. Look at table 4 in the Sui study. 100% of people don't die, but your risk from BMI > 30 jumps, and > 35 doubles. And in the later figures you see the most important variable was exercise, but do you think people with BMI >35 and older than 65 get much cardiovascular exercise in? If they're luck they don't need new knees by that age. It would be interesting to see if one of these studies would examine mortality by obesity + poor control of risk factors. I have seen enough of these patients already to know they get sick sick sick, fast fast fast. All it takes is some uncontrolled diabetes and you're up shit creek in no time.
The general advice is the lean horse wins the race. It will never be absolute, there are too many variables. But it is a mistake to say there is no risk from obesity. You can become obese and with good medical care we can offset most or all of the risks. But then there are two issues to consider:
1. Primary vs secondary prevention - it is better to avoid gaining weight and having to take half a dozen drugs to offset risk.
2. Mortality is not your only worry. With greater obesity comes higher rates of disability, illness, and poorer quality-of-life.
My advice is therefore stay as thin as you can, as long as you can. Exercise. And if you are obese treat your risk factors! This will likely extend your life better than weight loss (which is hard and often not successful). I have low expectations for weight loss, I would prefer people avoid obesity in the first place.
A couple recently have shown that low carb diets are more effective at promoting weight loss, and despite all the 'conventional predictions' to the contrary, have typically shown no significant effect on cholesterol levels - and have often exhibited a salutary effect on "good" cholesterol. I know, that's not the WHOLE story - some say that people on low carb diets self-limit their intake of foods, and most people will lose weight if they eliminate processed sugars, processed grains, and simple starches from their diets
geciktirici,
I suspect you are right, people can eat almost unlimited carbs. it's actually pretty hard to eat nothing but protein all day, and in the process you tend to make yourself ketotic which will depress apetite.
In the end, it's calories in, calories out. Metabolic rates do not vary hugely between individuals. And you know, it's pretty easy to measure it anyway. If you really believe it's different track your weight, calories and exercise for a week. If your weight remains stable, subtract your exercise expenditure from your total intake and voila, there's your basal metabolic rate. It's not going to differ from predicted, which you can find out too just by quick google searching, by more than a few percent unless you're sick. Now, if you want to lose weight, take this basal metabolic rate and eat about 200-400 calories less per day for a few months. Don't starve yourself. You will lose weight if you control your intake. It's just physics, and I'm not going to debate with people who say energy is created inside their guts contrary to the laws of physics.
Also remember some skinny people who seem to be able to eat everything aren't necessarily normal. Absorption is an issue, and it's funny, someone I know who for years as been thin as a rail despite eating endlessly (although finnicky) ended up getting diagnosed with celic sprue. But that explains people who are skinny despite large intakes - there is no inverse "super-absorber syndrome". You either absorb the calories that are there, or less. Skinny people may additionally be skinny because they are absorbing less.
Rather, "it's not going do differ much from predicted" - these are averages after all and people are different, but probably not by >10%.
Help me out with a little clarification, please. When you write "it is very difficult to make people lose weight, and attempts to design a scientificaly proven effective weight loss trial have been largely futile."
That seems to be saying that there is no evidence that it is possible to lose weight. Why is that? If it is doable, why is it so hard to prove clinically?
Also, you wrote "people are always exaggerating the amount they excercise versus the amount they eat to justify their "slow metabolism". I assume you mean "obese people" only? On NPR this morning they were talking about a study with hotel maids who are exercising all day, essentially, at work, but who don't think they get any exercise. There must be studies showing that overweight and obese people consistently exaggerate calories and exercise. Can you suggest some? I'd also love to find any studies showing that normal weight and underweight folks underreport exercise and overreport calories.
Thanks.
I see from your blog that you're one of Sandy's fans. I think you know the answers to both questions and are being intentionally obtuse.
If not, here goes:
The problem is on average if you enroll people into a RCT for weight loss there is no guarantee of a real motivation to lose weight. As a result, RCTs of various weight loss programs show, on average, very little weight lost for the intervention. This should be pretty obvious. The intervention only works if people are compliant, and the ones that work (and they exist) are difficult to comply with, so people don't. That doesn't mean it's impossible to lose weight, it just depends on individual motivation more than Jenny Craig. The averages then look crummy. No one in their right mind would suggest weight loss is impossible.
This paper from NEJM is relevant. A small cohort, yes, but the fact is the people who claim that their bodies violate the laws of physics are, in fact, eating more calories than they are accounting for. As you can see from the link, the many studies cite this link, and many that do confirm this original result. The obese overreport activity, and underreport intake. What the thin do doesn't matter, the issue is whether or not people can blame metabolism for their failure to lose weight. Either they are eating more than they say, or their bodies are violating the laws of physics. Not surprisingly, science finds that they are eating more.
I agree with some of what Sandy posts, and disagree with some. I'm trying to really understand what you're saying, and I'm trying to bring a skeptical mind to the issue.
>The intervention only works if people are compliant, and the ones that work (and they exist) are difficult to comply with, so people don't.
I don't know which ones you think work. But in cancer research, if you come up with a treatment program that no one can stick with, you don't say it "works". The ability to follow a treatment is an integral part of its success.
Hey, I agree with some of Sandy's posts too. She runs a about a 10 or 20% crank post rate, usually dealing with the specific issue of health effects of obesity.
And anyone can follow these diets, the issue isn't similar to cancer where the side-effects are so extreme they routinely cause hospitalizations and kidney and liver failure etc. The issue is motivation. You can't control for it. Studies of supplements show a similar problem. If people don't see an immediate need for an intervention or aren't battling an acute disease they slack. It's just human nature. It doesn't mean the interventions don't work, or are the cause of non-compliance, individual motivation is.
MarkH, I'm quite earnest about evidence-based medicine. Doctors (and patients) routinely fail to predict the pain and difficulties of chronic conditions and over predict the pain and difficulties of acute conditions. If "anyone can follow these diets" but we have no evidence of any of them working long term, then what does that mean? How can we expect people to adhere to treatments that haven't been proven? How can we blame them if the treatments haven't been proven?
Saying that "individual motivation" is the cause of diet failure has a strong whiff of the same sort of reasoning as "prayer only works if you really believe". It sounds like woo hand-waving.
If obesity is even indirectly responsible for a great deal of morbidity and mortality, from heart disease, diabetes, and cancers, then the side-effects of the diets (or failure to stick to them) are just as extreme. Many addicts do manage to give up their drugs, even when their lives are not in immediate danger. On what basis can we assume that overweight people are slacker than smokers, for example?
C'mon Kaethe, you're being disingenuous for sure now. Are you telling me that calorie restriction and exercise don't result in weight loss? It's funny you mention smoking as an example - another area that until the last ten years or so there was no clinically-proven anti-smoking therapy (mild improvements over placebo are seen with Wellbutrin and now Chantix). Does that mean you can't quit smoking? Because no clinical trial could show that chewing nicotine gum was much better than chewing a toothpick? Of course not. Should doctors have not encouraged patients to stop smoking because the success rate was low? Or because RCTs showed the interventions had low efficacy? Of course not.
Weight loss is physics. It's that simple. Energy intake and energy output. In the last 20 years that people have gotten so obese, there hasn't been the sudden appearance of some gene which improves metabolic efficiency by 100%. It's not some external agent making people overweight (other than the availability of increasingly high-calorie foods of course). People are eating too much, and exercising too little. It's that simple. The fact that non-compliance is a problem with RCTs of dieting interventions has no bearing on whether or not weight loss is possible, whether weight loss should be encouraged, or obesity is unhealthy. We know how to make it happen, we just don't know how to make people consistently do it. Just like quitting smoking, quitting hoagies and dove bars ain't easy. Exercise is hard. People don't want to take an hour out of their day to run, or ride a bike to work. You can't construct a trial where you hold a gun to someone's head and make them blast their abs, these trials are dependent on compliance, and that is what is critically lacking.
I find any other suggestion to be the real woo, because it implies that the laws of physics don't apply to biology. Turns out they do, and when people claim otherwise (as the studies built on the NEJM show) they are deluded.
As far as I can tell, anything will cause weight loss for six months to a year and nothing will keep the weight off thereafter, with all the lost weight eventually returning and then some. If short-term weight loss is a goal, then there's an effective treatment. But the problem is long term, isn't it? We're looking at chubby kids and trying to find a way to slim them down and keep their weight down for the rest of their (hopefully long) lives. We're looking at overweight or obese adults and trying to find a way to control their weight for 40 years. So, again, I'm asking: where is the evidence of something that works?
You say it's simple physics. White collar jobs involve sitting at a computer and blue collar jobs involve physical labor for eight hours, so then why are the blue collar workers the overweight ones? If it's simple physics, then why do professional dancers also have to starve themselves? Eight hours or more of exercise a day should make them the leanest of the lean.
The words "it's that simple" are suggestive of dogma, not evidence. Nothing about the body is that simple.
Actually, it really IS that simple. Blue-collar workers tend to be "meat and potatoes" eaters. They also tend to drink alcoholic beverages, specifically beer, that inhibits the body's normal metabolism. High caloric intake trumps the increased exercise.
There are things that work to maintain long-term weight loss. They are just REALLY unpopular in a super-sized culture. Look at fast food restaurant menus... everything has gotten bigger. When I was younger, I thought a Big Mac was a huge burger. Now we've got triple and quadruple cheeseburgers. It is very hard in this culture to eat sensibly, as I'm finding out with my wife struggling to lose weight. Burn more calories than you take in, and you will lose weight. To maintain that, you must retrain your eating habits. Again, in the absence of actual glandular or metabolic issues, it really is that simple.
If we're just looking for quick and dirty weight loss, tapeworms are always effective! So is methamphetamine. Both have nasty side effects, though... <grin>
LanceR, can you point me to some studies? That's what's making me crazy, really, is just finding the clinical evidence to back up the widespread knowledge.
Tapeworms could make a comeback, though, you're right.
Actually, what (in my opinion) leads to the extreme obesity mentioned above (450+) is in fact metabolic, it is due to insufficient basal NO. NO is what triggers mitochondria biogenesis, and if you don't have enough mitochondria, the body has to generate ATP via glycolysis. However it takes 19 times more glucose to make the same ATP via glycolysis than it does to make it via oxidative phosphorylation.
If you have 5% too few mitochondria, such that 5% of basal ATP is switched from oxidative phosphorylation to glycolysis, that takes twice as much glucose delivery to cells to support that. The vasculature isn't set up to deliver twice as much glucose without producing hyperglycemia. But then glucose transport into cells is active via GLUT transporters. To get more glucose into cells they need more GLUT transporters. Insulin increases GLUT numbers, but the important glucose concentration isn't in the bulk blood (the only place it can be measured), but rather in the fluid adjacent to the cell getting the glucose, in the extravascular space. Concentrations of glucose and insulin are lower there because the intervening cells consume it.
To preserve glucose and insulin for cells far from a capillary the organism must invoke glucose resistance and insulin resistance, as in the metabolic syndrome.
Where does the glucose go? It goes into lactate. Lactate can be recycled, but it takes mitochondria to provide the NAD to do so. If there aren't enough mitochondria in the liver and kidneys to do so, where does the lactate go? Into generating lipid, which every cell can do, where ever there are spare mitochondria. Liver, adipocytes, eventually muscle and even the heart. When ectopic fat starts to form in the kidney, you are at death's door.
The solution is to raise NO levels. Exercise can do it for some people. Intestinal parasites actually work great! They cause the production of iNOS which raises NO levels and triggers more mitochondria biogenesis. They have been used to treat Crohn's disease.
http://gut.bmj.com/cgi/content/full/54/1/87
http://www.mssm.edu/msjournal/73/7381098.shtml
http://www.ajtmh.org/cgi/reprint/66/3/304
One of the major symptoms of obesity, a hypermetabolic state, that is a basal metabolic state that is higher than would be expected from their lean body mass, suggests this. When fewer mitochondria are called to produce the same ATP, they do so by increasing the mitochondria potential, which increases slip and decreases the efficiency of ATP production. This is observed as more calories being needed to supply basal metabolism. When people lose weight and their mitochondria numbers go back to normal, their basal metabolism goes down because it is restored to normal efficiency.
While it is true that weight only increases when more calories are ingested than metabolized, the brain can only operate on carbohydrate or ketone bodies, not lipid. If you are not in ketosis, your liver has to make enough carbohydrate for your brain. It can make it from carbohydrate or from amino acids. It can't make it from lipid. If you don't have enough carbohydrate to run your brain, either you eat more, or you endure your brain "starving".
A lot of things mitigate against long-term loss. One is motivation among some people ("I just want to lose weight for this wedding"). Another is that if you are very heavy, your life must change in big ways in several directions, and that is hard to do (more exercise, portion control in a society that insists on lots of cheap, huge portions), and emotional eating that can have several causes. I found several causes for my non-hunger eating, and am working on them every day. But it's not one thing, because if it were, it would be easy to fix. What researchers should do is find long-term losers and study what they have in common in order to find some "rules for success."
I want to add a data point.
I retired three years ago.
Without conscious effort, my weight starting dropping at 1/2 pound per week.
The fat went along with the stress.
I have now lost 80 pounds.
khan, Your experience can be explained by my above post. Stress is a low NO state.
http://www.ncbi.nlm.nih.gov/pubmed/12070451?ordinalpos=16&itool=EntrezS…
Some of the details of how physiology is switched from a high stress low NO state (the fight or flight state) to a high NO state are discussed in my blog on the placebo effect.
http://daedalus2u.blogspot.com/2007/04/placebo-and-nocebo-effects.html
Raising your NO level by any method would be equally effective (I suspect).
Thank you, MarkH for this post.
Now I know I'm not the only one that was getting really uncomfortable with a lot of the posts at Junkfood Science. One of the reasons I hated it was because she was saying that what I did, and am doing, was impossible. I 'starved' myself so that people would stop hating me.
I lost 70 lbs in 2005, from about 205 to 135. (5'8") The 205 was my immediate post partum weight. I have kept the weight off. I didn't feel oppressed by my doctor, or discriminated against. My husband thought I was beautiful. I had good curves. I didn't feel fat.
But I was getting high blood pressure and didn't want to 'go there'. How do you drop blood pressure naturally (with no woo involved)? Exercise.
The equation really was that simple. I stopped eating bags of cereal while reading or watching TV, and started exercising. And I knew I couldn't stop exercising, once the weight was off. You know, I did look good. I didn't want to go back because I found out another thing:
I'm stronger. No more heaving myself off the couch and saying things about 'getting old'. I can do 30 squats in a minute. I'm happier. A lot of stressful things happened through this time, and I recovered from them quickly.
This is another thing Sandy rarely talks about. Painful backs and knees. Difficulty getting around. Breathing at night. Of course these are things that should be treated in an unbiased manner, without nagging, but they are also things that lower quality of life as a result of obesity.
Diets and exercise can't be a special intervention for weight loss that should be discontinued once the weight is lost. They should be a healthy, long term change. A healthy, balanced diet is as important to a skinny person as it is to a large person losing weight.
I am with Sandy on this one though: Bariatric surgery is really bad mojo.
Eat what my parents did? A steady diet of pasta and gelato it is :)
Props to you for "outing" Sandy Swarc. She's treated like an oracle among some mostly otherwise sensible FA activists, and it's outrageous. I'm pretty skeptical of received norms, and VERY skeptical of corporate-, government-, or media-sponsored concern mongering, and I used to think she was a true skeptic as well. The odd tone of a post denying any basis for concern about high-salt intake was my first clue that I might be wrong about her, and a recent post comparing educating children about balanced nutrition to hawking snake oil was the last straw.
I understood then the basis for the suspicion on the part of some folks that Swarc is somehow in the pocket of Big Food.
Another thing about the latter post was her attitude toward vegetarian and veganism. Not only was it wrong and dated, it smacked of ignorance and prejudice--exactly what she and the FA movement are presumably fighting. Here's a data point--I'm a lifelong (non-junk food) veg*n and I'm a model of health. And I look like a fitness competitor.
Also, a note--my grandfather, who is a (retired) physician and heart specialist, is of the opinion that if a person lived roughly past the life expectancy, s/he had a good chance of living into extreme old age. So, wouldn't that mean that among the very aged, the mere fact that they are still alive pointed to a fairly remarkable (i.e. non-typical) genetic profile?
All that said, there is merit to the FA movement. For a more objective and eye-opening look at the "obesity crisis", I would recommend Gina Kolata's book Rethinking Thin.
"I have low expectations for weight loss, I would prefer people avoid obesity in the first place."
Too bad you weren't around when I was little to tell my family to just let me be the active child I was and not to starve me. That's the problem, though. We don't encourage children. I despised gym class. It was the most horrific thing I had to go through, and I think as it exists in most schools, it should be abolished. It's all about competition and popularity contests.
But I swam and I loved to dance and I desperately wanted classes in dance or figure skating lessons. I'd have settled for a swim club... but no one seemed to connect the dots that an active Juliet would be a healthier and (likely) a naturally thinner Juliet.
Instead, I was given ridiculous portion sizes, left hungry all the time, and made to feel like I was inferior, like I was less of a person. Until the medical community is willing to address these issues associated with being an undesirable weight, there will never be a solution to the "obesity crisis."
you seemed reasonable, until you added your own nonsense that "Global Warming" was undeniable. Oops, even those in the Global Warming cult have retreated from that term, and now call it "Climate Change". Funny how they've been playing fast and loose with the data, too, eh? What about the repressing of people who disagree with the establishment line? Regarding Al Gore as hero rather than hypocrite?
So now I'd have to wonder what other flaws are in this article, because of built-in bias.