Aug 25 2009
Low-Carb Diets and Heart Disease
Eat a balanced diet, containing foods from all the good groups, especially fruits and vegetables.
There – for the vast majority of people that is all the diet advice that you need for overall health. Get regular exercise, don’t smoke, maintain a healthy weight, and have good sleep habits – now we have covered most lifestyle risk factors. If people followed this basic advice they would significantly reduce their risk of the most common diseases and disorders.
Often, however, I meet or hear people who add unneeded complexity to what it means to have a healthy lifestyle, even while simultaneously ignoring more basic advice. I can’t tell you how many patients I have who spend hundreds of dollars a month on useless supplements while they still smoke.
The media, weight-loss, and supplement industries are no help. They offer a constant barrage of complex, often conflicting, misleading, or downright false health information. Meanwhile, many people have lost sight of the basics.
Dieting for weight loss is the same. Everyone wants to know the secret to maintaining a thinner waistline. Low-carb diets have been all the rage for at least a decade, despite the fact that they don’t work. What does work is calorie control and exercise – eat a balanced diet in moderation and get regular exercise. Not always easy, but at least it is simple. (Again – this is for most people. Certain health conditions do require special diets.)
The major problem with most diet plans is that they are restrictive. They generally focus on good foods vs bad foods and counsel elimination of the “bad” foods from the diet. This makes it more difficult to get a well-balanced diet, and also reduces compliance. Most such plans will produce short-term weight loss from calorie reduction, but long-term failure. Ninety-five percent of people who go on a diet to lose weight will regain all of their short term losses within a year or two.
A recent study also suggests that low-carb diets may increase vascular risk. Researchers fed mice their regular diet, a western diet high in fat, and a low-carb/high protein diet. They found that the high fat diet had a 9% increase in atherosclerosis (clogging of the arteries) while the low carb diet had a 15% increase. Of course, this is an animal study so translation to humans is not clear. And it was a single study and needs replication. Prior studies have shown that low carb diets do not increase cholesterol levels, probably because short-term weight loss offsets any adverse effect from having higher fat content, but this is still not clear. What we need are long term studies in humans. This animal data is preliminary, but suggests that there is a potential problem and further research is warranted, especially given the popularity of low-carb diets.
This study highlights the fact that restrictive diets may have unintended consequences. Humans are omnivores and we are dependent upon a varied diet.
There is a principle in medical research known as the “intention to treat” model. What this means is that two or more treatment strategies are compared based upon as close to real-life experience as possible and the intention to treat with one or the other. Treatment A may be superior to treatment B in a carefully controlled clinical trial, but if in the real world compliance with treatment A is low because it is complex and unpleasant, while treatment B is cheap and simple, B may yield the best statistical outcomes.
With regard to specific patients I often tell my students that you have to make sure you don’t overwhelm them with details and with a complex regimen. Often the more important basics are lost in the complexity of fine-tuning. This is also part of the individualization of medicine – some patients can tolerate more complexity than others. A hectic executive, for example, may not be able to take a middle-of-the-day dose of medication.
What all this means, in my opinion, is that we need more public health education focusing on the basics – those things that are easy for most people to do that will have the biggest health benefit.
In terms of diet – eating a balanced diet in moderation with plenty of fruits and vegetables is what most people need to focus on.
49 Responses to “Low-Carb Diets and Heart Disease”
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Don’t forget to enjoy your food. A crabby diet book author might think that Julia Child’s life was cut short (age 91), but a fuller life for her is hard to imagine.
Fruits and vegetables, you say? You’re making me hungry. Mangos, persimmons, blueberries; kohlrabi, sweet potatoes, jicama — there are endless tasty adventures to color your dinner plate and dazzle your taste buds.
May a fully ripe durian wend its way into your domicile…
Um, on what evidence do you conclude that “eat[ing] a balanced diet in moderation with plenty of fruits and vegetables” is easy for most people compared with, say, taking supplements?
Do you have a link to the actual study you referenced? I’d love to know what kind of fat these animals were fed. More often than not it turns out to be a pro-inflammatory, high omega-6 vegetable oil, not the actual animal fats that all carnivores/omnivores evolved to eat.
And as you noted, rats are not humans. A high-carbohydrate diet is perfectly natural for them, so it makes sense that feeding them a diet that they didn’t evolve to eat would cause their health to deteriorate.
It’s an overstatement to say that humans are dependent upon a varied diet. Many traditional hunter/gatherer cultures have flourished on diets that show little in the way of balance or moderation. The Inuit thrive on little but fat and protein for the majority of the year, while the Kitavin consume an enormous amount of fruits and starchy tubers, and little animal fat or protein.
Egmutza, I don’t know if you can say that the Inuit thrive on their diet. Here’s a segment from a Toronto Reuters new report from Jan. 23, 2008:
“The Inuit in Canada’s far north have lifespans 12 to 15 years shorter than the average Canadian’s, government data showed on Wednesday, putting the aboriginal people on a par with developing countries such as Guatemala and Mongolia.
“At 64 to 67 years, Inuit life expectancy “appears to have stagnated” between 1991 and 2001, and falls well short of Canada’s average of 79.5 years, which has steadily risen, Statistics Canada said.
“Inuit now live as long as the average Canadian did in the 1940s, Simon noted in an interview. “We didn’t even have medicare (publicly funded health-care) then, so yes, this is pretty shocking.”
“Inuit have the lowest life expectancy among Canada’s three aboriginal groups, which also include Indians and Metis. Together, the groups number 1.2 million, or about 3.8 percent of Canada’s total population of around 32 million.”
Inuit people have higher rates of diabetes than anywhere else in Canada.
Granted, there are multiple causes for a lower life expectancy, but it seems naive to discount the impact of their diet.
Tip: listen to Robert H. Lustig (MD, UCSF Professor of Pediatrics, Division of Endocrinology) explore the damage caused by sugary foods. Especially the part on Ancel Keys and HDL, LDL (pattern B, small dense), VLDL (pattern A, large bouyant), triglycerides high-carb diets and the correlation between sugar (fructose) and CVD/CHD. Minutes 32.30 to 39.00. The whole lecture is very interesting btw.
http://www.uctv.tv/search-details.aspx?showID=16717
Another thing to consider is that the Inuit are probably not a good example of how we don’t need to vary our diet, especially right after pointing out how different fats have different effects.
A major wintertime staple of the traditional Inuit diet is whale blubber. This is not analogous to pork fat or partially hydrogenated vegetable oil. Whale blubber turns out to be the big secret behind why the Inuit don’t get scurvy in the winter — it’s unusually high in vitamin C and some other nutrients more traditionally obtained from plants.
So it’s not so much that they don’t eat a balanced diet, it’s that they have quite different sources than we’re accustomed to in more temperate climes. Also, as pointed out by TSkidC, “thrive” might not be an entirely accurate term. It is further worthwhile to point out that the Inuit weren’t exactly avoiding fruit and vegetables by choice. It’s just that non-animal food sources are scarce in an Arctic winter, and they found ways of surviving without them.
“No one, not even residents of the northernmost villages on Earth, eats an entirely traditional northern diet anymore. Even the groups we came to know as Eskimo—which include the Inupiat and the Yupiks of Alaska, the Canadian Inuit and Inuvialuit, Inuit Greenlanders, and the Siberian Yupiks—have probably seen more changes in their diet in a lifetime than their ancestors did over thousands of years. The closer people live to towns and the more access they have to stores and cash-paying jobs, the more likely they are to have westernized their eating. And with westernization, at least on the North American continent, comes processed foods and cheap carbohydrates—Crisco, Tang, soda, cookies, chips, pizza, fries. “The young and urbanized,” says Harriet Kuhnlein, director of the Centre for Indigenous Peoples’ Nutrition and Environment at McGill University in Montreal, “are increasingly into fast food.” So much so that type 2 diabetes, obesity, and other diseases of Western civilization are becoming causes for concern there too.”
http://discovermagazine.com/2004/oct/inuit-paradox
To Allison Cummins:
He doesn’t say it is ‘easy’ he says it is ‘simple.’ Granted he doesn’t lay out any evidence for this, but it is quite obvious. I don’t know how much simpler you can get than saying “eat a balanced diet, containing foods from all the good groups, especially fruits and vegetables.” It may not be a simple process for you, personally, but as a method it is quite simple. The application of it may be tough, but it will work if you apply it.
Thank you, s. I was going to post essentially the same response to TSkidC and Calli Arcale regarding the Inuit. My initial comments were with regard to the traditional Inuit diet. TSkidC, I’d also wonder if that study accounts for lower life expectancy due to infant mortality rates?
Calli Arcale, I agree that the type of fat one eats does matter, and that one does need a proper balance of *nutrients* in order to thrive. My only point was that from a meat/vegetable/fruit/grains perspective, one does not physically *need* balance or moderation (though for many, that may be the easiest approach).
And it’s irrelevant whether or not the Inuit ate the way they did by preference or necessity. The physiological effects of the diet remain the same.
Another point from the original post that irks me is the blanket statement that low-carb diets do not work. In most of the well-controlled studies I’ve read, they appear to work as well or better than low-fat diets, with some advantages in body composition and blood lipid profiles. A more accurate statement might be that people have a difficult time adhering to low-carb diets, not that they do not work as intended. But you could say the same for low-fat diets. None of them work if you revert to unhealthy eating habits.
egmutza,
I think you’ll find R Lustigs lecture on sugar and fructose metabolism and de novo lipogenesis interesting. His talk is about causes of childhood obesity. While doing so he essentially describes one facet of why low carb diets work, while high carb diets may not work. You’ll have to have som patience though as he reaches the details after 40 minutes in the talk. He is pretty acerbic in some instances (e.g. on exercise as a means to lose weight)
His lecture does also nicely complement the simplistic energy in-energy out discussion some months ago on this forum.
Keep in mind – the entire point of this post was to keep it simple – to oversimplify the data to those points that will have the biggest effect for most people. I deliberately glossed over a ton of complexity. That was the point.
And I stand by my position that low-carb diets do not work – in that there does not appear to be any long term advantage to the low-carb bit. Weight loss from these diets results from reduced calories, not the proportion of carbs. And the advantage is minimal and short term.
It turns out that prescribing a low carb diet as a strategy for long term weight control is a failed strategy – which is reasonable to summarize as – it doesn’t work.
Advising calorie control, exercise, and and a varied diet is simpler and a better strategy for overall health. There are still cultural issues with compliance and excess caloric intake that need to be addressed. But it is counterproductive to give people a lot of misleading cherry-picked information, when simple advise is in fact more accurate.
Right now the biggest predictor of long term weight loss – regular exercise. It is NOT low carb. In fact, what evidence there is for long term success favors low fat.
Steven, if I’m reading you right, you’re saying that when comparing people who stick to their low-carb diets against those who stick to their low-fat diets, the blood lipid and weight loss advantages tend to favor low-fat diets? If so, could you point me towards the studies you’re referencing?
I’d also like to see the studies that demonstrate that there is a causal relationship between exercise and long-term weight loss, rather than just an association.
I did not say anything about blood lipid data. The lipid data is actually mixed: http://www.ncbi.nlm.nih.gov/pubmed/16476868?ordinalpos=1&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_DiscoveryPanel.Pubmed_Discovery_RA&linkpos=5&log$=relatedreviews&logdbfrom=pubmed Also – most of this data does not control for the effects of weight loss itself and are short term.
But I was talking about long term advantage. I think the data shows that all weight loss diets are equally useless – their effects are modest and short lived. There is no good long term controlled data.
I am not advocating low fat diets. Again, the data strongly supports, in my opinion, calorie control – not a good calorie, bad calorie approach (e.g. http://www.ncbi.nlm.nih.gov/pubmed/18646093?ordinalpos=1&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_DiscoveryPanel.Pubmed_Discovery_RA&linkpos=2&log$=relatedreviews&logdbfrom=pubmed)
If we resort to long term retrospective or observational studies (I know, this is weak evidence) they tend to favor low fat for weight loss (not necessary other health factors).
Exercise is a strong predictor of long term success. I stress – long term. Short term, you need calorie restriction. Exercise prevent regaining the weight. http://www.ncbi.nlm.nih.gov/pubmed/19514637?ordinalpos=8&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_DefaultReportPanel.Pubmed_RVDocSum
If you put it all together you are left with the evidence supporting that for most people, for general health and weight control, calorie control, a varied diet, and regular exercise are the best advice. There is insufficient evidence to support any fancy diet or supplements.
To clarify the point about the Inuit – there is a difference between surviving and leading a healthy lifestyle. I never said you need a well-balanced diet to survive. I am saying the best synthesis of all available evidence is that a balanced diet is a good idea, and there is no evidence to support restrictive diets as a weight loss or overall healthy strategy.
Isolated populations living on restrictive diets are not a good source of evidence for this question as it is difficult to factor out genetics, other factors affecting life expectancy, and contamination with a modern diet.
It was just an irrelevant point.
Steve,
Thanks for the links for the links to the studies. I’m somewhat familiar the first one, and I don’t see anything in it indicating whether or not the participants actually stuck to the macronutrient breakdowns they were assigned. A little digging into the studies included in the meta-analysis suggests that (at least in the ones that kept track), many of them did not. So I’m not sure this tells us much about whether or not the diets work for those who stick to them.
As for the Inuit, it’s relevant because it demonstrates an example of the kind of foods humans likely evolved to eat. If high-fat, low-carb diets truly do cause vascular damage, shouldn’t we expect populations like the Inuit (prior to Western diet introduction) and the Masaai to be dropping dead from heart disease left and right?
I agree, it’s observational data and therefore limited in what it can tell us. But it’s at least as relevant to human nutrition as a study showing that if you feed rats a diet completely unsuited to their biology, one they couldn’t possibly have evolved to thrive on, that it’s bad for them.
There was an item in today’s news that a relatively modest amount of exercise – 70 minutes/week – has health benefits.
There is a scientific method of retarding the aging process.
1. Don’t smoke
2. Avoid excessive sun exposure
3. Lie
The first two items are to help you get away with the third.
egmutza – I think the data on low carb diets is weak, and not enough to recommend it.
But – I also agree that non-compliance is a major issue. That was a major theme of my blog today. If you give people a complex diet plan, especially one that involves a restricted diet, they are unlikely to comply. It is not a good long-term strategy.
So I would say that there is no compelling evidence that low-carb diets could work if people were compliant.
It doesn’t matter too much, because compliance is terrible anyway, in fact it is the dominant factor of success, and keeping a diet plan simple and convenient is therefore a dominant factor.
And – there may be unintended consequences to a restrictive diet.
I maintain that the Inuit analogy does not tell us much – as I said – genetics could be the determining factor there. And their “high fat” diet is very unusual, as others have pointed out. And I think you have created a false dichotomy – no adverse health effects vs dropping like flies. This is not relevant because we have already pushed life expectancy long past pre-industrial levels. Now we are trying to get to live even longer and healthier lives – past 80. Comparisons to pre-industrial populations are of little to no relevance.
I believe the term for “people who add unneeded complexity to what it means to have a healthy lifestyle” could be
orthorexia
(see http://en.wikipedia.org/wiki/Orthorexia_nervosa )
“an unhealthy obsession [...] with what the sufferer considers to be healthy eating [...though] it is not an official medical diagnosis, and it is not listed in the DSM-IV.”
Having some knowledge about the naturopaTHICK side of things, of course, not only is food more important than merely being nutritious, they consider food MEDICINE [yikes!].
And I observe NDs making piles of money misleading patients into believing their actual health conditions are due to not actual food allergies.
And, of course, there’s that bastion of food restriction orthorexia, Bastyr naturopath D’Adamo, who has created what amounts to a blood type based version of the the horoscope to guide your proper food selection.
-r.c.
Hi Steven,
I’ve been reading quite a lot of about low carb diets lately, and more specifically the role of insulin in fat loss/storage.
I’d be interested to get your take on this blog post:
http://sparkofreason.blogspot.com/2009/08/gut-feeling-about-insulin.html
It’s no study, but I feel that he gets much more in depth about the subject than I ever could and I’m inclined to agree with his theory. However it doesn’t seem to line up with your standpoint in today’s post ( toward the end he specifically refers to caloric restriction diets, and why they don’t work )
Any light you could shed on this topic would be greatly appreciated!
thanks,
-Simon
I hate these articles. They remind me that I haven’t gotten my fat ass to the gym in far too long.
You’ve also ruined my dinner plans for McDonald’s. Now I’m going to have to buy a salad to keep myself from feeling guilty.
Damn doctors.
Exactly what do fruits provide that green vegetables don’t? I am so sick of people sticking the two of them together when the only thing you will get from fruits that you don’t get from green vegetables is a mega dose of fructose and simple sugars. Green vegetables are already nutrient dense and low in carbohydrates and are the corner of most all low carb diets (other then 0 carb ones).
As for this rat study (barring the obvious fact that rats live on a primary carb diet and evolved that way and humans in no way did), how about this one
http://www.eurekalert.org/pub_releases/2006-11/hsop-a2s110606.php
(that actually involved real data and humans)
There are a ton of studies on cholesterol levels and other items but the study you’re using already said that it didn’t raise cholesterol so I will not bother posting them.
As for low carb diets don’t work there are a lot of studys
http://www.eurekalert.org/pub_releases/2004-05/dumc-sld051104.php
http://www.eurekalert.org/pub_releases/2004-11/bc-vld111204.php
http://www.eurekalert.org/pub_releases/2005-03/tu-soo030705.php
http://www.drbriffa.com/blog/2007/03/07/study-confirms-superior-effectiveness-of-low-carb-eating-for-weight-loss/
There are more than these (including a resent one that had a longer time period but can’t find it this afternoon) but out of time for today. If you don’t want to say they are better than anything else that’s fine but don’t say they don’t work. There are no diet studies that say low carb diets are non effective.
Very well done.
I always tell my patients it’s calories in minus calories out x genetic predisposition. Then I look for low hanging fruit ( no pun intended ). I ask THEM where do YOU think your problems are regarding diet ( drinking their calories, portion size, low nutrition snacks , etc ) and then I ask them to choose one, and only one thing to reduce. Keeping it simple and keeping it consistant is the key. As you know, only 500 less calories per day x 7 days is one lb weight loss per week. It usually is an asymptotic weight loss curve, but still , the greater one is overweight, the greater the actual weight loss. If all else fails I utilize a dietician.
There is some evidence in exercise physiology that suggests that vigorous weight training or interval training can even raise basal metabolic weight.
Finally, the other advantage that exercise has, particularly weight training, is that muscle mass is preserved as one loses weight; one preferentially loses more body fat, with visceral fat loss being the key, as compared to those who do not weight train.
basal metabolic rate, not weight
Steven
your dietary arguments are mainly out of moral superiority: bad people get fat because they eat bad and do not exercise (no I am not obese nor fat, actually quite fit). Secondly you do not take into account the evolutionary angle. You, and others (here and in previous posts on the sugar-diet-exercise topic) state that it is calories in and calories out, thus implying that exercise is all that is needed. But, as Robert Lustig, and many others before him, points out, how can you in that case e.g. explain obese 6 month olds that were born normal weight (and do not blame the mothers here)?
From an evolutionary point of view our metablism is rather built around the *energy out-energy in* concept. I.e. energy conservation and energy storage is fare more important. Thus making it difficult to waste energy and also not immediately gain weight after a famine (or, the modern society counterpart, dieting).
You alse state that pre-industrial diets are uninteresting. You couldn’t be more wrong. **Pre-agricultural diets** are very interesting from many angles. Nutritional, breadth of food choices, composition of foods etc etc. See e.g. The Evolution of Hominin, Diets, Hublin, Jean-Jacques; Richards, Michael P. (Eds.). for a fuller overview http://www.springer.com/social+sciences/anthropology+and+archaeology/book/978-1-4020-9698-3).
Without understanding the evolutionary basis of our adaptions to various aliments, it is impossible to say what diet is least likely to cause illness and bad health. What is clear though is that pre-agricultural (“paleolithic”) diets were low-carb, low-fructose (modern cultivars selected for sweetness are higher in fructose than wild cultivars), low-glycemic index, high non-cereal fiber and high in insect fats and omega-6 (from insects and fish), higher in mineral content, higher in vitamin content and so on.
While our modern especially post 1960-diets are high in glycemic index, high in fructose, high in “bad” fats etc are very different from millions of years of dietary evolution. Even cereals and milk are modernities in this aspect.
And in the US a major lifestyle and diet experiment has veritably been going on since fat was accused of causing obesity and CHD/CVD. Have the Americans gotten thinner or healthier? No, they’ve gotten a rampant obesity-CVD/CHD “epidemic” on their hands. It is here that R Lustig is very interesting to read and listen to. (Some of the slides in the UCTV lecture can BTW be found here: http://www.niehs.nih.gov/news/events/pastmtg/2007/cehr/docs/metabolicsyndromelustig.pdf.)
He argues that since the major shift in caloric intake has been an increase in the use of sugar (sucrose) and sugared beverages, the reason for obesity (and CVD/CHD) has to be looked for there. He proposes that it is primarily fructose caused de novo lipogenesis and effects on insulin and ghrelin that is the major problem. While glucose causes minimal de novo lipogenesis, fructose does quite the opposite. The sugars are metabolized very differently (see his pics for more info).
He concludes by comparing effects of ethanol exposure and fructose exposure (quoted from his slide-apologies for the usage of spaces making the table slightly winding):
Ethanol Fructose
Hematologic disorders
Electrolyte abnorm
Hypertension Hypertension
Cardiac dialtion
Cardiomyopathy Myocardial infarction
Dyslipidemia Dyslipidemia
Pancreatitis Pancreatitis
Malnutrition *
Obesity Obesity
Hepatic dysfunction Hepatic dysfunction
Fetal alcohol syndr Fetal insulin resistance
Addiction Habituation if not addiction
*My note: may occur if the “sugary” diet is “junky”.
Select papers by or co-authered by Lustig:
http://www.nature.com/nrendo/journal/v2/n8/full/ncpendmet0220.html;
http://circ.ahajournals.org/cgi/reprint/119/4/628;
http://www3.interscience.wiley.com/journal/120849117/abstract.
For additional select references on dietary studies and some research summaries see this page:
http://www.staffanlindeberg.com/OurResearch.html (the english pages are under construction).
The Kitava study results are very interesting in this respect.
And to help us always keep in mind to be skeptic even of medical studies see e.g. this article related to the sugary topic: “Relationship between Funding Source and Conclusion among Nutrition-Related Scientific Articles” (http://www.plosmedicine.org/article/info:doi/10.1371/journal.pmed.0040005)
“For interventional studies, the proportion with unfavorable conclusions was 0% for all industry funding versus 37% for no industry funding (p = 0.009). The odds ratio of a favorable versus unfavorable conclusion was 7.61 (95% confidence interval 1.27 to 45.73), comparing articles with all industry funding to no industry funding.”
Alison Cummins “Um, on what evidence do you conclude that “eat[ing] a balanced diet in moderation with plenty of fruits and vegetables” is easy for most people compared with, say, taking supplements?”
Have you been in a town that had a health food shop or chemists, but didn’t have a greengrocers? I haven’t. For most people it is pretty easy to walk past the supplement store and spend their money on a bag of apples instead. Since you have to eat ‘something’ you might as well get your vitamins from fresh fruit and veg rather than a tablet. I used to take all sorts of supplements, but apart from turning my urine various vivid colours they didn’t seem to do much else.
Going back to the original post to quote mine, this is the sentence most relevant to my concern: “I can’t tell you how many patients I have who spend hundreds of dollars a month on useless supplements while they still smoke.” The simple answer is to quit smoking. Improve your health, save money. But people choose to take supplements instead because that’s easy and quitting is hard… even though the supplements have no beneficial effect and may even cause harm, the simple answer is not necessarily the easy one.
In terms of diet, restrictiveness may actually make a diet easier to follow, at least in the short term. For an extreme example, that’s a significant reason for the popularity of diet drinks as meal replacements: you don’t have to think about a meal, learning new cooking methods — learning to cook — about portion control, about pleasure. You just down your meal replacement shake and move on.
I completely agree with the premise of the post, that following your Very Boring five-food-group recommendations with the high target of fruits and vegetables, and applying portion control, is the way to go. It was very beautifully put in the following essay: “Eat food. Not too much. Mostly plants.” http://www.nytimes.com/2007/01/28/magazine/28nutritionism.t.html?pagewanted=all
No argument from me.
The issue I have is that “simple” and “easy” are not the same thing. People may gravitate to the complex — and often ineffective — solutions because they are easier for them to implement.
The greatest risk factors for heart disease are age and sex. Simple, yes. But not easy to manipulate.
So rather than railing against people for irrationally choosing the complex over the simple, it may be more effective to acknowledge directly that what is simple — and effective — may actually be difficult, and to talk about that.
That was kind of what I was trying to get at too, actually, about it being a balance of nutrients that’s important (though don’t discount the need for roughage, and other more subtle impacts of a softer, more easily digested diet, such as dental caries and a tendency to overeat). I’ve not been expressing myself very clearly lately.
We do generally need some fruit in our diets, or we will get scurvy. There are very few non-plant sources of vitamin C, and what with marine mammals being protected species, I don’t think anyone realistically has the option of going with a traditional Inuit diet unless they actually *are* Inuit, outside of Japan and Iceland.
As far as comparing life expectancies of people in industrialized nations with pre-contact indigenous peoples, there are too many confounding factors. Firstly, the indigenous peoples generally had a life expectancy about half that of the industrialized people, largely due to the harsh conditions of their lifestyle and the lack of medical care. You’d never be able to tell if their diet made any difference, because they generally died before obesity-related heart disease would make much of a difference, and of course they weren’t getting obese generally anyway. (Modern Inuit living in a semi-traditional lifestyle still refer to the fat around their midsections as the “Eskimo bank account” — when you live off of your kills, you can expect to go days without food.)
They weren’t practicing balance, as you refer to it, but they *were* practicing enforced moderation.
I think it’s safe to say, however, that we did *not* evolve to live like Inuit. Only a very small percentage of the human race lives in the polar regions even today, and it is a hardscrabble existence if you want to go it without resupply from warmer climates. It’s possible to live like that, but that doesn’t mean it’s optimal.
Besides, there were aboriginal people who lived mainly off of vegetable matter. So I don’t think you can conclude based on any one tribe’s diet that it’s obviously how we evolved to live. I think it’s more clear that we evolved as omnivores, able to adapt to live on whatever was available in a particular territory.
S – your analysis is based entirely on a false assumption about what I am saying (although a common false assumption).
I was not writing about the cause of obesity, and therefore nothing I said can be interpreted as “moral superiorty” or the assumption that obesity is entirely caused by overeating and a sedentary lifestyle. That is a separate question I did not address.
For any individual, however, if they wish to lead a healthy lifestyle, eating in moderation and having a balanced diet and getting regular exercise is simple and evidence-based advise.
However, individuals do vary greatly in terms of their genetics and medical conditions. I specifically added a caveat to cover this. But also, saying someone would benefit from exercise is NOT the equivalent of saying they are fat because they don’t exercise.
Having said that – there is evidence to suggest that inactivity and overeating are associated with obesity, and this association is likely at least partially causative (not in everyone, but statistically).
Statement of facts is not moral superiority.
Zelocki – There is nothing wrong with eating fruit. Fruit is also nutrient dense, and if eaten in moderation should not be a problem in terms of calories. People should be aware, however, (for estimating their caloric intake) that fruit does contain fructose and can have more calories than they think.
Fruits are also very useful for children. Sure, I try to get my kids to eat vegetables, but they don’t eat enough. They can get a ton of vitamins from the fruits they like so they are healthful snacks for them. They are also both thin and high energy, so there are no concerns about excess calories with them.
It is reasonable to lump fruits and vegetables together as a food category because they have similar nutritional content. And, in general, people should be aware of the caloric content of their food.
Regarding low-carb diets – all the evidence, including your references, are relatively short term. They show a short term advantage only, that weight loss is usually very modest, and no long term advantage. In fact most of the studies used to show that low-carb diets work in fact show they do not work – after a year weight loss even in obese subjects is negligible – that’s a failure, in my book.
Hmm, checking back on your july 1 and 17 posts I notice you said (july 1) “Further, it is human nature to prefer quick fixes and easy answers to tough love. Weight control is not complex, but it turns out to be very difficult for most people. Will power is not enough for 95% of the population.” *and* “We can hardly blame people for what appears to be almost universal human traits.”, so I stand corrected.
The main cause of low-carb diets working is probably the decreased sugar (sucrose and HFCS) intake (if fruit juices, sauces and other sugarcontaining really is excluded). American consumption was about 5 punds per/p around 1900, 115 punds around 1970 and about 145 punds today…
You restate that: “there is evidence to suggest that inactivity and overeating are associated with obesity”. Research by Timothy Church et al (Changes in Weight, Waist Circumference and Compensatory Responses with Different Doses of Exercise among Sedentary, Overweight Postmenopausal Women, http://www.plosone.org/article/info:doi/10.1371/journal.pone.0004515) is rather interesting in this respect as it indicates an evolutionary truth: energy out = energy in/stored and not the opposite tedious statement of energy in/stored = energy out. I.e. that you just can exercise it off. This is because of evolutionary mechanisms ensuring that we as soon as possible “eat and store for bad times”.
Nature wants us fat!
Hmm just noticed Time had a feature about Churches and other related research (http://www.time.com/time/printout/0,8816,1914857,00.html) so I’ll quote straight out of Time: “On average, the women in all the groups, even the control group, lost weight, but the women who exercised — sweating it out with a trainer several days a week for six months — did not lose significantly more weight than the control subjects did. … Some of the women in each of the four groups actually gained weight, some more than 10 lb. each. … What’s going on here? Church calls it compensation,… Or they compensated in another way, by moving around a lot less than usual after they got home.
Looking over the list I see a push for portion control and calorie counting as if it was natural but probably one of the most unnatural diets. As pointed out in the earlier study, humans by nature deal with food as groups and don’t think of it as X portions or Y calories that will allow said human to function for Z hours. This is likely because there is no reason in nature to act like that. Just like an animal, if you have food and your hungry you eat. People overeat not because they don’t know how many calories they consume but because they remain hungry past when the needed amount of food is taken in. Overeating calories is a symptom of that and one of the main reasons calories restriction diets fail is because they don’t address the root cause of hunger(leading to cheating and eventually diet collapse).
High fat / high protein / low carb / high glycemic index diets all work on the theory that they reduce the hunger and that will naturally reduce the calories consumed as a byproduct. Either way, reduction in hunger is the challenge no matter how it’s done and the need to eat too many calories will fall off after that naturally.
You can also do the “eat really tasteless un enjoyable food diet” too or as I like to think of it the Japanese 3 big bowls of tasteless white rice a day as the main portion of your meal diet because if you make eating enough of a chore it doesn’t matter how hungry you are.
Zelocka – what you are saying is the low-carb theory – but it is really not evidence based. The fact is, low carb diets fails long term. The short term advantage probably is related to hunger, but it also seems that the body just adjusts to the new food source and the hunger advantage goes away.
What is clear is the weight control is about calorie control and regular exercise. How to accomplish calorie control is difficult and complex.
Here is a summary of what I think we can say now about strategies for calorie control:
- Keep it simple. Complexity is not sustainable for most people
- Weigh yourself once a week. This is critical feedback in order to make adjustments.
- Meal substitutions are helpful – probably because they have fixed numbers of calories
- Estimating caloric intake is very helpful (not necessarily cumbersome calorie counting). Just keeping a food diary doubled weight loss in one study. People also need to have a basic awareness of the calorie density of common foods.
- AND – we probably need cultural changes, i.e. healthier choices need to be easier to make and need to be the default choice.
(I submitted this earlier, but my later post is showing and replied to and this was not so trying it again)
Here are some more as long a term as you get from these studies.
http://www.nutritionandmetabolism.com/content/3/1/22
http://jama.ama-assn.org/cgi/content/abstract/297/9/969
http://content.nejm.org/cgi/content/abstract/355/19/1991
http://content.nejm.org/cgi/content/short/359/3/229
I dislike the dismissal of no long term studies have been done because no long term studies of anything are ever done for the most part. Frankly the fact that we got to two years on one beats out most medicals studies I have seen done. I would also like longer studies but medical studies tend to be short and poorly designed in order to get something out the door fast to justify research money. That plus any diet study that relies on self reporting is inherently questionable but this is as good as has been done and nothing bigger is coming.
As for fruit, I frankly would rather have a kid eat a multivitamin most of the time. Sure its fine in moderation but then again pretty much everything always is and equating the two as being on the same level nutritionally when one has a much higher sugar and calorie rate for the same nutritional value is strange. Yea you can bribe kids into eating fruits because they are basically natural candy but that doesn’t make them wonderful things.
<"- AND – we probably need cultural changes, i.e. healthier choices need to be easier to make and need to be the default choice"
Good luck at removing artificial sweeteners (yes those too), soft drinks, candy, sugary sweets, chips, HFCS-added bread, cakes, sugary sauces (ketchup, mayo and so on) etc etc You advocate a major shift in food production practices.
The main reason that your suggested strategies won't work are:
(1) that it require a good amount of self-discipline and no "secret" snacking between meals.
(2) that it may induce a state of starvation in some of the individuals thus inducing our dear body to start conserving energy and making the dietary intervention more difficult to sustain.
Both low fat and low carb diets will fail long time due to evolutionary constraints.
Zelocka – the 2-year study you cite supports my position. See my analysis here (http://www.theness.com/neurologicablog/?p=337)
All the weight loss occurred in the first five months, then subjects regained weight (although not all of it) and in the end total weight loss was very modest and only slightly different among the three groups. FAIL.
You anti-fruit bias is bizarre. Fruit is nutritious and enjoyable. That’s a good thing. For those for whom calories are not an issue, they are great. If calories are an issue, then just eat fruit in moderation.
Your stated position was “Low-carb diets have been all the rage for at least a decade, despite the fact that they don’t work.” I was providing proof only that they do work as well as other diets not that they are the best diet. (While I believe they are the most effective diet there is not enough evidence to support that at this time)
In this case, they where only really following low carb for the 20 a day section. 120 carb a day after that is moderate carb at best and no low carb diet would jump from 20 to anywhere near that so I agree it’s a flawed study, but then again we work with what we have.
I am not anti fruit, I just believe that fruit is a treat not a primary food group and should never be expected to be a primary nutrition delivery system and more then Nuts should be. If you’re trying to lose weight on a low calorie diet you should be mostly avoiding them altogether. Sure if you don’t have a problem controlling your weight they are fine but we are not talking about people without weight issues here.
Steven
On the topic of very low carbohydrate diets, I was wondering if you have an opinion on their role in the treatment of various neurodegenerative diseases? There seems to be rekindled interest in the anti-epileptic effects of a ketogenic diet, and this new study in particular, on the use of a ketogenic agent to treat Alzheimer’s, caught my interest:
http://www.nutritionandmetabolism.com/content/pdf/1743-7075-6-31.pdf
It seems this new possibility of reversing the development of Alzheimer’s by inducing ketosis with coconut oil or MCT fats is gaining quite a bit of attention in the Alzheimer’s community.
I hate to refer to this, BUT I LOVE IT:
regarding “your anti-fruit bias is bizarre”
Terry Gilliam’s “Time Bandits” has that great scene
where Michael Palin says [I'm paraphrasing somewhat from memory]:
“Pansy, pansy. My problem, it has begun…
I must have FRUIT.”
-r.c.
“All the weight loss occurred in the first five months, then subjects regained weight (although not all of it) and in the end total weight loss …FAIL.”
The study as most similar does not support anything about weight, they just support that metabolism slows with caloric restriction. End of story. Really pointless studies (read flawed) as long as they do not take into consideration evolutionary mechanisms when analyzing the results. R Lustig has at least a good hypothesis on causality with his fructose high de novo lipogenesis rate ideas.
OTOH good primate studies (e.g. “Caloric Restriction Delays Disease Onset and Mortality in Rhesus Monkeys” http://www.sciencemag.org/cgi/content/full/325/5937/201) running over decades indicate that there are other advantages as e.g. better general health, decreased incidence of diabetes etc
Zelocka: Fruit is a major part of primate diets (with leaf, nuts, tubers insects, eggs, small mammals and other apes etc depening on species), so why do you believe it is not a primary food group for humans too.
Steven: Re you “summary of what I think we can say now about strategies for calorie control:”. Here is an even simpler rule: skip soft drinks, cookies, candies, sugared sauces (store bought ketchup, dressings etc), cakes, bread with sugar, fast foods.
Calorie counting and food diaries. Ha ha, self-delusion I say
As I said before: “Nature want’s us fat”.
I think your referring to primary food source differently than I am in this context. Sure primates eat pretty much anything but they do have to go find it and no matter how much they like fruit they put in a lot of calories to go get it. After you eat leaves and bugs you need something to get the taste out of your mouth. In addition, Primates never get bitchy about not fitting into a size 2 swimsuit so worrying about their figure it pretty much a human only behavior.
There is no question that humans can survive on a fruit diet as long as protein was included since the body is pretty good about converting nutrients. My argument is that it is not a critical part of the diet and can be replaced by green vegetables that have comparable nutritional density if you’re worried about weight.
I see your caloric restriction and raise you a BMI in overweight has lowest chance of death because I do so love contradictory studies.
http://www.medicinenet.com/script/main/art.asp?articlekey=85050
I think it’s worth mentioning that the study this post is referring to used apoE -/- mice.
Here’s an example (note: I’m not affiliated with taconic):
http://www.taconic.com/wmspage.cfm?parm1=901
The model description is especially telling, especially the following little tidbit:
“Mice develop normally, but exhibit five times normal serum plasma cholesterol and spontaneous atherosclerotic lesions”
I won’t go on about the points already made by you and other posters about mice (omnivores with a strong herbivorous bias, at least in the wild), high fat consumption, and what it may or may not mean in relation to human health.
Perhaps the following study is more meaningful, as it could safely be argued that a porcine model more closely approximates a human model for this sort thing:
http://www.nutritionandmetabolism.com/content/3/1/39
I raise you with this heavy tome “New developments in obesity research” Lawrence F. Ditmier (ed).
I especially liked this comment covering all angles
“Unfortunately in the overfed Western world, people who are this thin are often suffering from clinical and subclinical health problems, are smokers, had pathological conditions during childhood or, in the case of the elderly, suffer from lack of money to eat adequately. However it appears that very lean people who eat a well balanced diet, exercise regularly, don’t smoke, have satisfying lives and receive good medical care tend to be the healthiest.” (TT Samaras, page 3-4, chapter one)
BTW the rest of chapter one is good reading about realtion between height, weight, BMI and health.
The book you have there has a great deal of supposition (its basically a textbook) but no independent data that in anyway addresses the study I sited above. The theory that the normal and underweight had other factors was controlled for in the original study.
From the original Jama article
“We explored the effect of using different models with additional terms and interaction terms. Models with only sex, BMI, and smoking were fitted, as were models that used, in addition, race, alcohol, educational level, and height, as well as interactions of BMI group with sex, race, or smoking. Although some of these terms had coefficients that were statistically significantly different from zero within 1 or more subgroups, the effect on the parameter of interest (excess deaths) was not large, and the broad pattern of results did not change. The highest number of deaths associated with BMI 30 or greater was 137 696 for the simplest model, which included only sex, BMI, and smoking; the lowest number was 79 449 for a more complex model that included all listed variables and an interaction of smoking with BMI group.”
http://jama.ama-assn.org/cgi/content/full/293/15/1861?maxtoshow=&HITS=10&hits=10&RESULTFORMAT=&fulltext=BMI+low+death&searchid=1&FIRSTINDEX=0&resourcetype=HWCIT
I am not sure if I know what the generally meaning of low carb is? Does this still include fruit usually?
That depends on the diet but yes berry fruits (generally low in carb content) are usually Ok at some non introduction stage including strawberries raspberries and blackberries. Even more regular fruit is not that bad as long as its eaten raw and not as juice though checking the carb content and making sure it fits with your plan is always best.
Well so much for this study being anything other than crap. The mice in question here had been genetically modified to have no ApoE engineered to be susceptible to atherosclerosis. Since ApoE is needed to clean up fat in the blood it’s no wonder they developed Atherosclerosis and other issues directly related to that. That’s what I get for not reading the original study data.
On ApoE and what it does
http://en.wikipedia.org/wiki/Apolipoprotein_E
Kudo’s to this blog for pointing this out
http://diabetesupdate.blogspot.com/2009/08/studies-shed-light-on-falsification-and.html
Zelocka,
“The book you have there has a great deal of supposition ”
You missed some sarcasm “heavy tome” and “covering all angles [smiley]” before the quote of the silly para.
Are you surprised that the study is crap? I re-refer to “Relationship between Funding Source and Conclusion among Nutrition-Related Scientific Articles” (http://www.plosmedicine.org/article/info:doi/10.1371/journal.pmed.0040005)
Secondly lots of the skepticism here really is argument from authority (in the form of unskeptical references to studies in prestigious journals — as the JAMA study. Yes you are very correct in pointing out that you need to know what rats are used and what chow they get before being able draw any sensible conclusions. And then there is the evolutionary angle without which many discussions and studies on diet are useless. Evolution is Occam’s razor in this case.
BTW. A nice review that highlights the problems of the definition and the simplistic “a calorie is a calorie” of LC diets is “Low-carbohydrate nutrition and metabolism” (American Journal of Clinical Nutrition, Vol. 86, No. 2, 276-284, August 2007, http://www.ajcn.org/cgi/content/full/86/2/276)
Odds and ends: “The great tragedy of Science-the slaying of a beautiful hypothesis by an ugly fact.” (Thomas Huxley)
“The growth of knowledge depends entirely on disagreement” (Karl R. Popper)
Some skeptical lessons: http://www.thincs.org/unpublic.htm
Different calorie sources are definitely handled differently by the body – no one is doubting that. The question is, what is the net health effect of modifying macronutrient ratios? I maintain that the literature as a whole shows that any differences are minimal, any advantages very short term, and the complexity and loss of diet variety in the end is not worth it. It turns out not to be a helpful strategy.
Meanwhile – exercise and calorie control are hugely useful.
What I am advocating is that we keep our eyes on the ball, and not get distracted by minutia, even if it does sell more books and products.
A small gem found on the net: http://wholehealthsource.blogspot.com/2009/07/diet-heart-hypothesis-stuck-at-starting.html.
Related to the arguments against LHCF diets (“A recent study also suggests that low-carb diets may increase vascular risk…) and on evidence in general.
A quote:
“The distribution of blood cholesterol levels between the three groups was virtually identical. The study also found no association between egg consumption and heart attack risk. Dietary cholesterol does not raise serum cholesterol in the long term, because humans are adapted to eating cholesterol. We simply adjust our own cholesterol metabolism to compensate when the amount in the diet increases, like dogs. Rabbits don’t have that feedback mechanism because their natural diet doesn’t include cholesterol, so feeding them dietary cholesterol increases blood cholesterol and causes vascular pathology.
….
Reading through the short-term controlled trials, I was struck by the variability and lack of agreement between them. Some of this was probably due to a lack of control over variables and poor study design. But if saturated fat has a dominant effect on serum cholesterol in the short term, it should be readily and repeatably demonstrable. It clearly is not, so I’m left wondering why diet-health authorities are so certain of themselves on this point.”
/s