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Still On That Low-Carb Diet

by Steven Novella, Dec 14 2009

I have never been a fan of the low-carb diet craze – Atkins, South Beach, or whatever version you prefer. To me this was always a triumph of marketing over science. It is also an excellent example of how public opinion can be largely swayed by a few proponents and a compliant media, while the science goes off unnoticed in a different direction.

Dieting is also one of those issues that is more emotional than one might at first think. I have had the experience on more than one occasion of giving someone, in a very dry and calm fashion, my assessment of the evidence about low-carb diets, only to be met with righteous anger as if I had just trampled on a core tenet of their faith.  People are often touchy about what they eat and how much they weigh, and for those who have lost weight and credit a low-carb diet, the published evidence seems irrelevant. “Well, it worked for me” is the almost ubiquitous response.

I also think that people have far too much confidence in their ability to estimate their own caloric intake. The suggestion that perhaps they consumed fewer calories on the low-carb diet and that was responsible for their weight loss is met with outright denial.

There have been some recent studies that cast further doubt on the efficacy and even safety of low carb diets. But first a little background.

The literature on dieting is vast and complex, and we must separate out many distinct questions. Different diets can be assessed for their efficacy in weight loss and control, their heart health, their risk for diabetes, satisfaction, and their overall healthfulness. Evidence also needs to be considered for short term and long term effects. Long term weight control efficacy seems to be largely a factor of ease of compliance.

Like most medical/biological questions, the clinical literature is complex and there are no perfect studies – so how the strengths and weaknesses of various studies are considered can have a dramatic effect on one’s overall opinion. Some studies are too short, they vary in how they monitor compliance with the diet and other variables such as exercise, and on which outcomes they measure. Weight, of course, is the obvious parameter to follow, but there is also mood, cholesterol, insulin levels, and cardiac and diabetes risk.

My quick summary of this complex literature is as follows:

- The evidence strongly supports the conclusion that weight loss and control is dominantly (if not completely) determined by caloric intake. All diets that result in weight loss do so by reducing calories, and the macronutrient make up of those calories is irrelevant (to weight loss). Apparent advantages of low-carb diets are likely related to decreased hunger, which results in decreased caloric intake – but this effect is short term (3-6 months at most) and there is no long term advantage.

- Weight loss diets, in general, do not work. Most dieters will experience short term weight loss, but about 95% will fail to maintain their weight loss long term. Regular exercise seems to be critical for long term weight management (and is good for overall health), as is making lifestyle changes in eating habits, rather than “going on a diet.” Even still – most dieters fail. This likely means that we need to focus our attention on cultural, lifestyle, portion-size, and food manufacturing variables rather than individual dieting as a public health strategy to reduce obesity.

- Low-carb, high-fat diets are likely not heart healthy, although this data is mixed. It seems that there are negative effects of a high-fat diet, but these are offset in the short term by weight loss. So if one loses weight on a low-carb, high-fat diet the net effect is positive for heart risk factors. But since weight loss on such diets is almost always short term, the long term health effects may be negative. But evidence is mixed.

A recent study adds to this literature. Researchers did a randomized controlled trial comparing low-carb (20% carbs and 60% fat) and low fat (60% carbs and 20% fat) diets for 8 weeks. All food was weighed and logged and designed to provide 500 calories less than expenditure. All subject lost weight on this diet to the same degree, supporting prior evidence that calories, not macronutrient content, determines weight loss.

They also found that insulin parameters were the same between the two groups. So there does not appear to be any difference in terms of risk of diabetes. However, they did find an increase in arterial stiffness in the low-carb group. This could translate to increased cardiovascular risk. Other studies have also linked low-carb diets to increased atherosclerosis, which would explain the increased stiffness.

A 20 year epidemiological study, however, showed no increased cardiovascular risk from low-carb diets. So as I said, there is reason for concern about the heart effects of low carb diets, but the data is inconclusive.

This latter study also found that getting fat and protein from vegetable rather than animal sources was associated with lower cardiovascular risk. And this highlights another bottom-line conclusion from the literature – the focus on low-carb vs low-fat may be entirely misplaced. For weight loss and maintenance, portion control and regular exercise seem to be the key factors and macronutrient ratios seem to be irrelevant.

In order to avoid type II diabetes, weight control is key. But also it may be helpful to eat low glycemic index carbohydrates – those that turn to sugar more slowly and therefore have less of a demand on insulin function.

For heart health, the amount of total fat may be a factor, but this is unclear. What is clear is that they type of fat is a significant factor. Vegetable sources of fat have a protective effect, while animal fat increases cardiovascular risk.

In other words – how much carbs vs fat one eats should not be a major concern, and may be largely irrelevant. While the types of carbs and especially fats is important for cardiovascular health.

To summarize, in my opinion here are the best diet recommendations that can be made from existing evidence:

- Eat a varied diet, mostly plant-based

- Limit carbohydrates with a high glycemic index (simple sugars and starches)

- Do not diet for weight loss. Rather, employ reasonable portion control and exercise regularly.

- Whatever you do for weight control, make sure it is sustainable long term. You should be happy with your diet and exercise should be fun and convenient. Anything that seems burdensome will likely not last and be of no long term utility.

- And most importantly – completely ignore diet fads, diet books, or any product that promises easy weight loss. They are scams.

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74 Responses to “Still On That Low-Carb Diet”

  1. Like everything else, people believe what they want to believe. It doesn’t matter how reasonable or scientific the opposing view may be.

    Great article – informative and helpful to those who are genuine and open to facts.

  2. Nayr says:

    Eat fewer calories? Exercise? How dare you? Being overweight has absolutely nothing to do with over eating or lack of exercise and there are absolutely no health problems associated with being overweight, you, you, you douche hound. If you had been reading the fat acceptance blogs you would know that.

  3. Dan says:

    I have a directly related question to this, but first let me say that I always enjoy reading and hearing your thoughts on the whole weight loss issue. Excellent article.

    My question is this: Are you familiar with the arguments from the anthropological and biological position regarding the so called “Paleo Diet”?

    While it intrinsically seems to fall into the arena of the naturalistic fallacy, it does seem to not be as much a diet for weight loss choice as a diet for ethics choice. That said, I do know people who espouse it because they firmly believe that it has helped them lose, and maintain a lower weight.

    I suppose the core of my question is that is this position simply another one of those fallacious arguments, or is there some truth to the matter?

    Thanks for the great science, Steve!

    • LovleAnjel says:

      My feeling on the PaleoDiet: I don’t use PaleoMedicine, PaleoClothing, or PaleoShelter, so I’m not too interested in PaleoFood either.

      • Jared says:

        Your genes might be.

        We do have better medicine. We do have better clothing. We do have better shelter, but we certainly aren’t healthier.

        Maybe you should rethink your cute little response.

      • idlemind says:

        . . . but we certainly aren’t healthier.

        Is that a fact? Or one of those things that “everybody knows” but has no science supporting it?

      • Jared says:

        A fact.

        This may not be conclusive enough for you:

        http://en.wikipedia.org/wiki/Paleolithic_diet#Research

        “Based on the subsistence patterns and biomarkers of hunter-gatherers studied in the last century, advocates argue that modern humans are well adapted to the diet of their Paleolithic ancestor.[126] The diet of modern hunter-gatherer groups is believed to be representative of patterns for humans of 50 to 25 thousand years ago,[126] and individuals from these and other technologically primitive societies,[127][128] including those individuals who reach the age of 60 or beyond,[129][130] seem to be largely free of the signs and symptoms of chronic disease (such as obesity, high blood pressure, nonobstructive coronary atherosclerosis, and insulin resistance) that universally afflict the elderly in western societies (with the exception of osteoarthritis, which afflicts both populations).[4][12][126] Moreover, when these people adopt western diets, their health declines and they begin to exhibit signs and symptoms of “diseases of civilization”.[11][126] In one clinical study, stroke and ischaemic heart disease appeared to be absent in a population living on the island of Kitava, in Papua New Guinea, where a subsistence lifestyle, uninfluenced by western dietary habits, was still maintained.[129][131]“

      • Tim says:

        Consider that the relative absence of those chronic conditions in primitive societies may be a result of them not having modern medicine therefore dying earlier, or the benefit could be due to other factors associated with their lifestyle, a hunter gatherer will hunt and gather, that is exercise many people don’t get.

      • James says:

        Wikipedia??? Should I be laughing???

        Even the citations listed on the page are weak!

        I don’t know if I would use that argument, that cavemen ate this and they did okay! I mean the life expectancy of our ancestors was incredibly low. I don’t see how a diet based on this could be considered more beneficial than “modern” food.

        If the premise is that we eat more plants than animals than I’m all for it, I just think that whole idea is based on a false premise. Given their low life expectancy and infant mortality I don’t see how their diet could really be considered a better alternative than, “western” food.

      • Max says:

        Our ancestors’ diet included unclean water and periods of starvation, and they had other challenges to their life expectancy. I don’t think anyone recommends returning to that.

      • LovleAnjel says:

        You’re just upset because I’m pithier than you.

        I would consider myself healthier than any cave woman. I have seen their bones– no thanks, rickets and yaws! I also still have all my teeth, thanks to a lack of rock dust in my processed vegetable matter.

  4. kat says:

    I used to do the high protein, low carb thing – when i was 17/18 – and *tried* to do it when i was 21 – and i always craved carbs and i never lost weight – i was in the ‘healthy range’ anyway

    another time, a couple years ago, i became kindof obsessed and went on this extreme diet, I ate about 500 calories a day, and worked out about 5 days a week for an hour and a half. in about a month and a half i lost 20 lbs. and i did more bad than good to myself by doing that to be honest

    I think you’re right in your article – that we should be getting our food from plants mostly. I have this book, Prescription for Nutritional Healing, and it says to prevent cancer you should avoid meat and especially deli meat. pretty much the diet to heal everything in that book is lots of vegetables. And I also imagine it would be hard to get obese if you’re a vegetarian or mostly vegetarian.

    • It’s actually pretty easy to be fat and a vegetarian. I was one, and know lots of fat vegetarians.

      No meat in cookies, cakes, pies, breads, pastas, etc.

      • Max says:

        Yeah, I knew this Indian vegan guy who loved his potato chips. He had a triple bypass in his 40′s.

      • Gary says:

        thats exactly what my sister did….replace the meat with high calorie, simple sugar carb desserts and others. She gained weight.

        Consider this, humans from various parts of the world have different body types, some long and narrow, others shorter and heavier,etc., adpated over time to the environment in which they lived. You can be heavy (compared to someone from another region of the world) and still be healthy.

    • Dan says:

      Yeah, I am pescitarian and I am at a weight-loss plateau. It’s just as easy to be vegetarian and be fat as it is to be an omnivore and be fat. It’s just a matter of caloric intake > caloric output in the long term.

    • Max says:

      Quackwatch on “Prescription for Nutritional Healing” http://www.quackwatch.com/02ConsumerProtection/FDAActions/global.html

      “From a scientific viewpoint, the book’s advice is loony from beginning to end, but the dietary supplement industry loves it because it enables retailers to refer their customers to an ‘authoritative’ source of advice for nearly every problem the customer may have.”

      Also, you might want to look up orthorexia.
      http://en.wikipedia.org/wiki/Orthorexia_nervosa

  5. Somite says:

    In line with this article, what worked for me was tracking and educating myself on how to estimat meal caloric contents. The best way I found to do this was an iPhone app called “Lose it!” http://bit.ly/Qs3Us It is free and is nothing more than a journal that helps you estimate caloric input and outputs. This works well for me since I can take advantage of my iPhone obsession. I am in no way affiliated with the developers.

  6. Steve, what is your take on the safety of gastric bypass?

  7. Cthandhs says:

    My husband did Atkins and lost a ton of weight! Oh, and he also started walking, then jogging every day…

    The big problem I have with Atkins is that’s I’ve seen people lose weight while doing it, but it snaps right back on. The diet doesn’t teach you how to eat, it cuts out sugar, which cuts back a lot of calories, but when you stop dieting, there’s no plan for going forward, it’s just back to sugar binging.

    • Patrick Brown says:

      Well, supposedly there is, but like most diets, people don’t follow the maintenance program, they go back to their old eating habits. With obvious results.

    • Jared says:

      The point is that you never stop dieting!

      You change how you eat. You don’t eat sugar anymore.

      If you start eating sugar again, you’re not following Atkins. The maintenance is to keep eating that same way. You will not starve yourself to death.

      • Cthandhs says:

        Keep eating the Atkins way and you may not starve to death but you get kidney stones. That was our doctor’s diagnosis.

  8. oldebabe says:

    Dieting, except for special diets for medical reasons, has always seemed to me to be a waste of time, a sort of mental `fiddling’ (I use this instead of the more accurate and obvious word) and futile, to try to lose weight or to maintain health. Just eating less and/or less often, period, is the answer for the majority of people, and the rest of it is just someone else making money, as you say.

    I did hear of a program for those who are sincere (which may be the sticking point) about permanently losing weight that I thought was simple, honest, and sensible: find and set the appropriate pattern, follow it until it becomes a habit and you no longer need to think/obsess about it, and… Voila. Too easy?

  9. Joshua says:

    I think people like diets because they get immediate results. Healthy lifestyle changes, as opposed to jumping on a diet fad and starving yourself for a month, take a really long time to build up a visible effect.

    This is just an anecdote, but still: Within the past couple of months, I’ve been getting a lot of compliments from my friends, especially the ones I see relatively infrequently, about my weight loss. So what have I been doing differently lately? Well, nothing… But, last year, I took up bicycling and started monitoring my diet because my doctor was concerned I might have hypertension. Nobody noticed any change last year, because there wasn’t any, but after a while I noticed how loose my trousers were feeling and eventually bought new ones a size smaller than what I’ve been wearing since after college. So I’ve lost weight, but it took over a year for the loss to be noticeable.

    On the other hand, I have a younger brother who put himself on a crash diet and began working out to an almost ridiculous degree. He lost a lot of weight really quickly. The weightlifting he did made him look pretty healthy, too. A year later, though, he had gained back a lot of the former pudge, because it’s just not possible to maintain a crash diet and intense workout regimen like he had for that long. (Unless, I suppose, if you’re in a line of work that expects you to, like professional athletes and bodybuilders.)

  10. Max says:

    I bought some bagels recently, and the package said, “Eat more bread,” and it showed the 1990′s food pyramid recommending 6-11 servings of bread and pasta. This kind of stuff makes me cynical.

    The public is thoroughly confused because the studies seem to be all over the place, and the guidelines keep changing. Pasta is out, oil is in, margarine out, butter back in, milk out, eggs back in, multivitamins out…
    I even read that exercise doesn’t help people lose weight because they reward themselves by eating more additional calories than they burned.

    Controlled experiments usually measure a few parameters like cholesterol over a short term, so conclusions about overall long-term health tend to be overblown.
    Epidemiological studies examine long-term morbidity and mortality, but they have hidden variables.

  11. Rowan says:

    One of the things I love about the Weight Watchers plan is that it starts you off and says, “Hey, this is how much food you should eat for your size and activity level,” and it’s usually *more* than people were eating because they were starving themselves and denying themselves food. It also lets you ‘buy’ high-calorie snacks by exercising, which basically drives home the “sweets and fats aren’t evil, but they have a *cost*” message. The in-out tracking helps a lot of people get a better understanding of their relationship with food.

    When I started tracking my calories, I was dangerously low, as in ‘falling more than 500 calories SHORT my basal metabolic rate most days’ low. I’d tripped my body into starvation mode, so that even though I was buring 1000 calories I wasn’t taking in most days, I was still gaining weight because my metabolism was shutting down noncritical processes (skin health, hair growth, concentration, blood to extremities). When I balanced that out, the weight *fell* off, literally.

    The person above who said that most people don’t correctly estimate their calories was right. When a friend and I were discussing our diets (‘diet’ as in ‘eating habits’ not ‘diet’ as in ‘weight loss program’), we both thought we’d eaten about 1800 calories the day before. When we added it up on a calculator website, I’d had 1300 and he’d had over 3000. He had underestimated the caloric density of everything he ate, and I’d assigned much more value to a plate of stir fry and some ice cream than they actually contained (turns out if you don’t feel like rice, a bowl of tofu stir fry is only like 200 calories of veggies and sauce…). Both of us were WAY off on portion size.

    The best weight loss advice I’ve ever seen is to pick the habits to maintain the size and lifestyle you want to have, and live as close to those as you can until you reach it, by which time maintaining your health and weight will be a habit, not a grind. If you’re seriously obese, then pick the habits to maintain the size you want to be in, say, six months, and keep moving that goal forward to make sure you’re not doing bad things to yourself by shorting your basal metabolic rate (the amount of energy it takes to keep your organs functioning). But “pick healthy lifestyle habits and stick to them,” doesn’t make a very catchy book title.

    • Cthandhs says:

      My family has done pretty well with wight watchers, the only thing I don’t like about them is they tend to shill over-priced diet food (at least in my area), which kind of hurts the portion control aspects of weight loss. Otherwise, the message is great, eat less, exercise more and pay attention to what you’re eating.

      • Max says:

        “Expensive food” diet, eh? Caviar, truffles, and filet mignon. Instead of watching your weight, just watch your wallet.

  12. Except you’re wrong on two counts.

    First, you say the amount of carbs/fat does not matter, then you say do not eat high glycemic carbohydrates. So you admit that a calorie may not just be a calorie. This guy would agree with you:

    http://www.youtube.com/watch?v=dBnniua6-oM

    If you look at the studies for childhood obesity, real measurements, there has not been caloric intake increase in any group except teenage girls. However, the % of carbohydrate vs. fat intake has increased, probably high glycemic carbs, and obesity has skyrocketed at every age.

    There is very strong evidence that there is something wrong with the food that most Americans are eating. It isn’t necessarily about the carbohydrates. It’s about the food itself. However, if you do cut out the food that is the problem, you will necessarily decrease your carbohydrate intake.

    The second point is that you make the claim that high fat diets are less healthy. This is a dangerous claim that helped get us in this obesity mess in the first place. And as a skeptic it is one you should be highly skeptical of, as it has never been conclusively shown in 30 years of literature.

    http://nccam.nih.gov/research/results/spotlight/030607.htm

    This study, the participants with the highest fat intake had the best health markers.

    http://www.menshealth.com/men/nutrition/food-for-fitness/saturated-fat/article/b675909829731110VgnVCM10000013281eac

    This article is a good summary of where studies have gone wrong with fat intake.

    There is a whole chapter in the book “In Defense of Food” as well.

    Basically, you’re following the government food pyramid, which, over the last 30 years has had completely abysmal results. The only reason every single diet works, no matter how bad it is, is because what Americans eat right now is worse than any single diet out there, even the worst fad diet. We are eating garbage. Every new food product that comes out is worse than the last.

    I think you should try a fad diet. I recommend the Paleo approach as mentioned above. If you’re skeptical, try it. What do you have to lose? It’s easy to follow after that too. You just don’t eat neolithic foods, period.

    • Max says:

      NCCAM study, unsigned article in Men’s Health…
      Why not just reference Atkins’ book?

      What’s funny is that both the Harvard and Stanford study cited in Men’s Health concern women’s health.

      “If you’re skeptical, try it.”

      As soon as I’m done with MonaVie, magnetic bracelets, and Kinoki foot pads.

      • Jared says:

        Peer reviewed study from the Journal of the American Medical Assocation. Yeah, that’s a real controversial Journal… (It’s not a NCCAM study, I merely linked from there)

        The main study doctor is a vegetarian. The diet study recommends Atkins. You think there is a conflict of interest there?

        I was not citing Men’s Health as an authoritative source, more a summary of where so much research has gone wrong. If you don’t agree with their conclusions that’s fine, but certainly you have been hearing the call that Saturated fat is not the demon that it has been made out to be? If there were definitive studies to the contrary, you think a popular magazine like Men’s Journal could run this article?

        The point of trying paleo for 30 days is more a personal experiment in seeing how food affects you. You may be sensitive to gluten and not know it. You may be insulin resistant and not know it. You can’t know until you experiment with your own body. It isn’t that hard, and what you learn from it is invaluable. There is no reason why every american shouldn’t try something like this at least once in their life.

        These kind of food experiments are becoming more and more popular with this paleo ‘fad’:
        http://www.urbangetsdiesel.com/2009/07/change-your-life-in-thirty-days.html

        http://robbwolf.com/?p=1046

        You will only hear more about this. I don’t think the 15 minutes for paleo are up yet. There are a lot of research scientists pursuing the hypothesis:

        http://www.thepaleodiet.com/published_research/

        The approach of this ‘fad’ has not been the same as many in the past, like Atkins, or Zone, or South Beach. This is a group of research scientists that are now influencing nutritionists. The nutritionists are now selling the books, and the research scientist books are becoming more popular.

      • Max says:

        I should’ve said NCCAM-funded study.
        NCCAM is the bane of Dr. Novella’s existence.

        “If there were definitive studies to the contrary, you think a popular magazine like Men’s Journal could run this article?”

        Of course. Sloppy science journalism is the other bane of Dr. Novella’s existence.

      • Jared says:

        I would accuse him of the same.

        In the same article he talks about how low-carb is a fad, he recommends eating less high-glycemic carbs.

        Also, the controlled study he mentions, I can’t read, but they controlled the food intake, I assume the carbs they gave the study participants were not hostess white bread and twinkies.

        Also, I don’t know what kind of fat they gave them. It could have had a completely skewed omega-6 to omega-3 ratio, like many believe is a problem in inflammation and heart disease. It could have been all heavily-processed fats.

        Low-carb may be a ‘fad,’ but I think it’s just not the whole picture. Instead of worrying about the quantity of macro-nutrients, we should be worrying about the quality. Low-carb just happens to usually improve food quality (maybe not in a controlled study, however)

        http://en.wikipedia.org/wiki/Medical_research_related_to_low-carbohydrate_diets

        You can’t really ignore all of the research. There have been significant results in this diet ‘fad.’

    • Max says:

      The fine print of the NCCAM-funded Stanford study.
      http://www.hsph.harvard.edu/nutritionsource/what-should-you-eat/carbohydrates-full-story/index.html#good-carbs-not-no-carbs

      “If you read the fine print of the study, though, it turns out that few of the women actually stuck with their assigned diets. Those on the Atkins diet were supposed to limit their carbohydrate intake to 50 grams a day, but they took in almost triple that amount. The Ornish dieters were supposed to limit their fat intake to under 10 percent of their daily calories, but they got about 30 percent from fat.”

      And the effect was predictably short-term:

      “The women in all four groups steadily lost weight for the first six months, with the most rapid weight loss occurring among the Atkins dieters. After that, most of the women started to regain weight.”

      • Jared says:

        Yes, they were on the road to gaining weight back, on average. That doesn’t mean that some women didn’t stick to eating the way the diets prescribe.

        I thought the most interesting result was that the highest fat group lost the most weight, and had the best health markers.

        The Atkins group was the only statistically different diet group, in both weight loss and health.

        So no, they did not follow the diet to the letter, but they did better than the group that was told to eat less calories and follow the government food pyramid. Which is pretty much what you are suggesting here.

        The proof of the study is not that they can follow diets, but what is the best thing to tell people? Apparently it’s better to tell them to eat all the protein they want, don’t worry about fat, eat veggies. Whatever it is that Atkins say.

        My belief is that telling them to follow a paleolithic approach would have even better results on average.

        The point is, Atkins is provably better advice over at least a year long period of weight loss on average than sticking to this only worry about calories, eat sweets sparingly mantra. You can’t argue with that.

      • Max says:

        It’s all consistent with Dr. Novella’s original post.

        Apparent advantages of low-carb diets are likely related to decreased hunger, which results in decreased caloric intake – but this effect is short term (3-6 months at most) and there is no long term advantage.

        The Atkins group may have found their diet less palatable, so they ate less calories and lost weight for the first 6 months.

        It seems that there are negative effects of a high-fat diet, but these are offset in the short term by weight loss. So if one loses weight on a low-carb, high-fat diet the net effect is positive for heart risk factors. But since weight loss on such diets is almost always short term, the long term health effects may be negative.

        The Atkins diet had a positive effect for heart risk factors, but that may be due to the short-term weight loss.

        I bet if you put obese people on an “unpalatable food” diet, they’ll also lose weight and improve their heart health markers.

      • Jared says:

        No. It’s not consistent.

        The Atkins group did NOT eat a statistically significant amount less calories. They just ate a larger percentage of their calories in fat! Less carbs, about the same amount of protein.

        Also, the other diet groups also improved their heart health markers but not as much!

        And, the types of food the people ate on average changed. That is the reason why the effect is temporary, they up their calorie intake, and they up their intake of carbohydrates throughout the year long study. It doesn’t have anything to do with the food only temporarily decreasing their hunger. It has everything to do with being overwhelmed by bad food choices that taste better. By being surrounded by other people eating our American diet.

      • Max says:

        “The Atkins group did NOT eat a statistically significant amount less calories.”

        The CDC says 3500 calories equals one pound of body fat. A 5-pound difference over 365 days comes out to about a 50-calorie difference per day. Is that statistically significant?

        “Also, the other diet groups also improved their heart health markers but not as much!”

        They didn’t lose as much weight.

  13. MadScientist says:

    Isn’t any unsupervised diet, for example, the “CSIRO Wellbeing Diet”, nothing but a fad? The great thing about diets is that there’s a huge market to exploit since the vast majority of people know next to nothing about nutrition and metabolism.

    • So you’re saying that people can’t maintain their weight without help?

      I just think they’re getting seriously bad advice from everywhere they look. Like, the government, and even this blog post.

      Apparently 30 years ago, people didn’t need dieticians as much as they did today. This was before the government told them to eat less fat, and get 6-11 servings of grains.

      You can’t say people need a supervised diet, when the % of obese people has gone up so much, and all that has really changed is the food available to us.

      I think it’s bad supervision that’s the problem, not the lack of supervision.

      • MadScientist says:

        It certainly isn’t only the food; it’s also the change in the body’s metabolism as we age (or develop various diseases like diabetes). Years ago I put on a lot more weight just eating the same old stuff I always ate – and less than I used to eat at that. So I stuffed myself with more rabbit food and tried to do more exercise – and I managed to lose weight at a rate of ~1kg per month. That’s nothing close to what the fad diet sales people claim (I lost X pounds in a week!), and I didn’t waste a cent on diet books. There’s a fair amount of discipline involved though – it takes a long time to train yourself to eat less and there is always the temptation to skip the exercise (in which case no diet will do you any good in the long term).

      • LovleAnjel says:

        One of the dietary changes over the past few decades has been portion size– even if a restaurant is using the same recipe it did 30 yrs ago, an individual serving is much larger now (as in, 2-3x the size of a serving from the 50s). Over time, people have normalized large portions and don’t know what a ‘proper’ serving of something looks like anymore. It’s hard to regulate your eating if you don’t know what to look for.

  14. Jared – the high glycemic index thing does not appear to matter for weight control. It may be bad for glycemic control and risk of diabetes. It is definitely bad if you have diabetes.

    But not weight. That is all about calories and activity. Any differences between type of calories appears to be too negligible to detect with studies.

    There are certainly differences between people, but for any individual person the way to lose weight is to reduce calories, increase activity. Adjusting macronutrients does not work.

  15. Gary says:

    And then there’s the Blood Type Diet. Eat Right 4 Your Type By Peter D’Adamo.
    My Dad buys this waste of trees and ink and tells me that since I’m a type “O” I can eat meat. He’s naming off all the things I can and can’t eat. I mention that I love peanuts but they give me a bit of an upset stomach. “Type O’s should eat peanuts, that’s why you get an upset stomach”, he says.
    Couldn’t it be, possibly, because peanuts are difficult to digest and thats why I get an upset stomach? Nope! Peter is a doctor, he’s right.
    “This claim is unsubstantiated by established biochemical research” is a statement of no use to my father…….or any other uneducateds.

    If dieting is a religion, who would be the Pope?

    • Gary says:

      …..should NOT eat peanuts…..

    • MadScientist says:

      An upset stomach could mean you have some intolerance to any number of substances in peanuts – or it could be mild poisoning from fungi. Do you get an upset stomach if you have fresh steamed peanuts or fresh roasted peanuts as opposed to peanuts which have been sitting on the shelf for months before being roasted/fried? I find that I cannot eat most brands of packaged peanuts; I grew up with peanuts fresh out of the ground and most packaged stuff has a distinctly rancid taste. Of course rancidity is only an indication of oxidation of the oils in the peanut – but if they’ve been sitting in air long enough to turn rancid, they may also be harboring all sorts of toxins from fungi or bacteria.

  16. MadScientist says:

    Hehehe; I was just reading some website on the “Paleodiet” – what a load of nonsense. At least the paleodiet will not be harmful to most healthy individuals – it is simply a subset of current diets. The “eating organ meat” bit may not be so good for people suffering gout, but I’ve got some great non-paleolithic recipes for ox tongue, cow and pig innards, cow pig and chicken blood.

  17. Paul Brookes says:

    Steve–I would seriously recommend reading Good Calories Bad Calories by Gary Taubes, which is an exhaustive review of the diet research over the last hundred years or so. A lot of current dietary advice is based on very flimsy research.

    The science behind low-carb diets rests on suppressing insulin production, which is the primary regulator of fat metabolism. Because of this, all calories are not necessarily equal. Bear in mind that the most radical dietary shift has been the increase in carbohydrate consumption over the last forty years or so — the result being that the population has become ever more obese.

  18. Kurt says:

    I personally lost 90 lbs on a low-carb diet. It works primarily because it requires discipline and produces quick results which is helpful for someone who is very overweight as I was. Sure, it’s probably not good for you — but so is being ~300 lbs. A low carb diet is clearly the lesser risk.

    OTOH, if you think you’re “a little heavy” and need to lose less than, say, 40 lbs, a low carb diet seems foolish. You’ll develop awful eating habits that will add the pounds right back on as soon as you begin eating carbs again. Low carb diets should probably be reserved as a “shock treatment” for the very obese.

    With regard to the study cited above, I’m not sure how good a test it is. The study used 20% carbs for “low-carb” and that’s way higher than most low-carb diets I’m familiar with. On my diet I was using a 30g limit (which is 120 calories, more like a 5% carb ratio). So, in terms of proving that carbs don’t matter this is NOT adequate to falsify the concept. I’m not saying low-carb really is more effective — I don’t know. It could simply be psychologically effective for some dieters.

  19. AdamK says:

    I tried this diet and was thrilled at the weight I lost.

    Turned out my scale was broken.

  20. Rachel says:

    I am continually going on and off a low carb eating plan. By low carb, I don’t mean the Atkins diet of eating lots of bacon and cheese but mostly eating lean proteins and low glycemic vegetables and avoiding starches and sugars. I don’t keep returning to the low carb plan for weight loss, since I don’t really lose much weight. I eat low carb for the other benefits, at least for me. The first 3 days of low carb eating is really hard but after that, I have more energy and need less sleep. I handle stress better, think more clearly and just generally feel better. I find myself bounding out of bed in the morning. After the first 3 days, I don’t crave carbs, as long as I keep my daily carbs below 100g. Low carb eating curbs my appetite, so I don’t experience the cravings of other diets. So, with all these great benefits, why don’t I just stay on a low carb diet for life? In a word – alcohol. You really can’t have alcohol at all on a low carb eating plan, or you will start getting carb cravings. I’m not an alcoholic but I find I have more fun socially when I’m drinking and the peer pressure to drink is huge. I’ve even considered telling people I’m taking a medication that doesn’t allow me to drink. So, I’ve found over the years that I’ll go off the low carb eating plan for months at a time, only to come back to it because I miss feeling as great as I do on the low carb plan. A low carb eating plan probably isn’t right for everyone but I probably have blood sugar issues, so it’s great for me.

  21. Becky says:

    I have found that eating good wholesome foods to be very beneficial. Janice Stanger’s latest book “The Perfect Formula Diet,”covers this very basic scientific-based diet. In her book she also covers the great diet myths that are out there. Very helpful book.

  22. Paul Brookes says:

    Now that I’ve more time, to extend on my previous post:

    Exercise and weight loss
    Your blog post and comments allude to the fact that exercise significantly increases weight loss. However, the majority of the literature doesn’t bear this out; in most studies, a diet-only group loses about the same amount as a diet-plus-exercise group.
    The biggest meta-analysis I could find was this one (http://tinyurl.com/mph5h5) in the International Journal of Obesity. It reviewed 493 studies and found little difference between diet-only and diet-plus-exercise cohorts. There’s also a Cochrane Review of diet-plus-exercise in women post-childbirth that comes to the same conclusion.
    What I’ve often seen is scientists doing these kind of experiments, not getting the result they were looking for, but coming to the conclusion they originally wanted anyway.
    Abstracts often state ‘significant’ weight loss for the diet-plus-exercise groups; however, when you read the actual paper, it turns out they mean statistically significant but not clinically significant. I’m personally not prepared to do an hour’s vigorous exercise a day for three months just to lose another half a kilo in total.
    The worst example of this was this BBC article (http://news.bbc.co.uk/2/hi/7530345.stm) urging readers to do an hour of moderate exercise a day, five days a week, to ensure optimal weight loss, based on a University of Pittsburgh study. However, when I read the paper, it stated: “Weight loss did not differ among the randomized groups at 6 months’ (8%-10% of initial body weight) or 24 months’ (5% of initial body weight) follow-up.” It turns out that the conclusion was arrived at via our old friend post hoc analysis.
    This is not to say one shouldn’t do any exercise; the cardiovascular benefits are well-known and diet-only groups tended to lose some muscle mass. But a simple calories in-calories out model is naive.

    Calorie sources are irrelevant
    I have to take issue with this as well. I’m curious you quoted the Diabetes paper when there are better-quality, longer-term studies that do show differences (such as http://jcem.endojournals.org/cgi/content/full/88).
    There are also studies among rural poor people who were eating very high-carbohydrate diets, but at levels that were considered sub-optimal by the UN (in terms of calories per day). Despite this, a good proportion of them were still obese, even though your logic predicts they should all have been malnourished.

  23. kabol says:

    i eat very little. i don’t like sweets all that much.
    but damn that beer. liquid bread and 20 extra pounds much?

  24. Kitapsiz says:

    I see no mention of genetic factors that contribute, combined with dietary habits …

    And screw that primarily plant based diet. Wait, better to make the point thoroughly, fuck the primarily plant based diet.

    I love cow, lots of it, especially wrapped with bacon … oh yeah, love that, best ever. Some yard carp is okay, just not too often, and definitely, tons of mussels, shrimp, crab and lobster … SMOTHERED IN BUTTER … the real stuff, actual cream/milk fat butter …

    As an aside; this is pretty much the favored diet of people in my bloodline, 80% of whom live past 95 years of age.

    COW, the only food stuff, everything else is just garnish or appetizer.

    • kabol says:

      well – that does it for you, kitapsiz: the crucifix foreheaded cow is going to get you.
      in 2012.

      hey – i’ll raise a glass of beer in your honor, crucifix-headed cow willing.

      • Kitapsiz says:

        WTH?

        Have you no dedication to your own species kabol? Traitor.
        Are there no honorable hominids left in this world?

        Turning me over to the Divine Crucifix-headed Dinner Platter God, and nary an ounce of shame to be found.

        (probably a vegan spiritualist)

        Oh how far the mighty have fallen …

  25. How efficient is a low-calorie diet for weight loss? I am on Low calorie diet.

  26. Paul Brookes says:

    To extend on my previous post (although your system hasn’t let me post this three times).

    1. Exercise and weight loss
    Your blog post and comments allude to the fact that exercise significantly increases weight loss. However, the majority of the literature doesn’t bear this out; in most studies, a diet-only group loses about the same amount as a diet-plus-exercise group.
    The biggest meta-analysis I could find was in the International Journal of Obesity (1). It reviewed 493 studies and found little difference between diet-only and diet-plus-exercise cohorts. There’s also a Cochrane Review of diet-plus-exercise in women post-childbirth that comes to the same conclusion.
    What I’ve often seen is scientists doing these kind of experiments, not getting the result they were looking for, but coming to the conclusion they originally wanted anyway.
    Abstracts often state ‘significant’ weight loss for the diet-plus-exercise groups; however, when you read the actual paper, it turns out they mean statistically significant but not clinically significant. I’m personally not prepared to do an hour’s vigorous exercise a day for three months just to lose another half a kilo in total.
    The worst example of this was a BBC article (2) urging readers to do an hour of moderate exercise a day, five days a week, to ensure optimal weight loss, based on a University of Pittsburgh study. However, when I read the paper, it stated: “Weight loss did not differ among the randomized groups at 6 months’ (8%-10% of initial body weight) or 24 months’ (5% of initial body weight) follow-up.” It turns out that the conclusion was arrived at via our old friend post hoc analysis.
    This is not to say one shouldn’t do any exercise; the cardiovascular benefits are well-known and diet-only groups tended to lose some muscle mass. But a simple calories in-calories out model is naive.

    2. Calorie sources are irrelevant
    I have to take issue with this as well. I’m curious you quoted the Diabetes paper when there are better-quality, longer-term studies that do show differences (3).
    There are also studies among rural poor people who were eating very high-carbohydrate diets, but at levels that were considered sub-optimal by the UN (in terms of calories per day). Despite this, a good proportion of them were still obese, even though your logic predicts they should all have been malnourished.

    • Max says:

      The calories-in-calories-out model still works. As I explained above, the reason exercise doesn’t work is that people burn 300 calories exercising for an hour, and then reward themselves with 300 calories of ice cream.

      According to the model, the calorie source could cause weight gain if it somehow reduces the calories-out, say by slowing metabolism.

      • Paul Brookes says:

        Well, your first point is kind of right. The problem is that light exercise doesn’t expend a significant amount of calories. Vigorous exercise, on the other hand, will simply increase appetite in most people, cancelling out any calorific benefits.

        The second point contains ‘could’ and ‘somehow’; you’d have to point to a plausible mechanism to back up this theory.

      • miconian says:

        In my experience, regular exercise makes me feel better about myself and my body, which makes it psychologically easier to resist eating junk. It also helps regulate my appetite, as it becomes much easier to tell when I’m truly hungry vs. just when food seems like it would be a nice salve.

  27. miconian says:

    I actually don’t think the South Beach guy would disagree with this post at all. The whole point of SB is to reduce intake of refined sugars and flours, i.e. high glycemic index carbs.

    I’m not an advocate of South Beach in particular. But in general, you seem to be working with a straw man assumption that people who go on low-carb diets believe that there is something magical about calories from low-carb foods that make it take more of them to add up to a pound of excess body fat. Please give at least some of the dieters a little more credit. The idea is that eating a low-carb diet keeps your insulin under control, which leads to fewer pangs of “hunger” when you aren’t really hungry, which, yes, leads to fewer calories. I’m sure that there are plenty of people following low-carb diets who don’t understand this, and simply make the link between low-carb and weight loss. But their error is in being reductive, not in getting the whole picture wrong.

    The problem here is that there are reductive statements happening on both sides of the argument. Yes, calories are what matter at the end of the day, and yes, all foods contain calories. And yet, it’s also true that nobody is going to get fat from eating raw apples. An apple contains calories, and a brownie contains calories. But one of them is going to leave you feeling fuller and take your body a while to break down, while the other is going to dissolve in your stomach right away and leave you feeling hungrier than you did before you ate it. For someone who has managed to “detox” from their sugar cravings and shifted to snacking on apples, then yes, of course it’s infuriating to hear someone tell them that weight loss is really just a matter of calories and portion control. Portion control is much easier with some foods than with others.

    • redundant says:

      miconian said basically what I was going to say. I have just lost a lot of weight on SB and have enticed three people at work to follow my example and they have had success as well. But, aside from the anecdotal evidence, SB has much more to it than “low carbs, high fat”.

      Only the first two weeks of the diet, Phase I, are basically without carbs, fruit, etc. Phase II reintroduces plenty of carbs, but they are low GI carbs. SB keeps you away from processed, simple carbs that turn to sugar right away. Multigrain breads, low GI fruits, etc are encouraged. Protein is provided by small portions of meat. The fats recommended are Omega 3s, olive oils, etc. The calorie reduction comes from not feeling hungry. Low GI foods take longer to digest.

      There is nothing hoakie about it. Just look at the recipes in the book, they are healthy and balanced. Simply put, SB is about staying away from processed and eating the most elemental foods as possible. It even says in the book, the bigger the better. Whole grains versus enriched white bread, whole apples rather than juice.

      Finally, what I like about SB is it teaches you how to eat and how keep the weight off. The author of the original book now has one out that includes how to incorporate exercise, because he recognizes exercise is key as well.

      I am not a shill, really. (s) Like miconian, I just don’t want to see it misrepresented, because I think it can really benefit people.

  28. Mike says:

    Steve,

    First just wanted to say thanks for the great SGU podcast. The combination of SGU, Carl Sagan, and Richard Dawkins have changed my world view for the better.

    Until recently, I would have been one of those people that said “Well, it worked for me”. Under the care of a endocrinologist (I’m type 2) and dietitian, I went on a protein-sparing modified fast and lost about 50 pounds within a few months. I was thrilled. I was able to discontinue most of my meds, other than metformin, and I felt great. Over the last couple of years though, I have gained back about 20 pounds, even though I have been mindful of my calorie intake on a daily basis, so I have to agree with you: Diets don’t work in the long term.

    Now, this has left me disappointed and confused and I don’t seem to be able to find consensus in the scientific community regarding the best way to maintain long term weight loss. The physicist in me says a calorie is a calorie, but my anecdotal experience seems to tell me otherwise. If I eat 1500 calories worth of decent food (complex carbs, protein, lower fat) versus 1500 calories worth of junk food, I seem to get better results from the former. Do you feel that there is no advantage, in terms of weight loss, from consuming the same amount of calories from decent food versus junk food? Does being diabetic change the answer to the question?

    Thanks.

    • Mike,

      This is basically speculation, but I’m wondering if the proportion of calories actually absorbed is different. I know that high fiber foods can reduce the absorption of micronutrients. Might the absorption of macronutrients (and therefore actual calories absorbed) be similarly reduced by dietary fiber?

      And then there’s the question of whether the calorie content of the fiber itself is included in those figures. If the calorie count is derived from burning the food and measuring the resulting temperature change in a fixed volume of water, the result is going to be a calorie count that includes the energy stored in the fiber, and those calories are definitely not absorbed. There are, apparently, standard corrections for that, but I don’t know how accurate they are.

      • Max says:

        The sugar lactulose is prescribed as a laxative, which definitely reduces the absorption of nutrients. NOT a recommended way to lose weight.

  29. Brian M says:

    My weight loss solution: Not to care. Be happy with yourself, as long as you are healthy (which I am). See how easy that was! Quick and convenient too. I am full of Win today.

  30. Ray Jan Saavedra says:

    My weight has its ups and downs. I can run a marathon when I’m at my best shape @BMI 22-23 and sometimes get so out of shape that I can barely walk 5 floors up a building @bmi 29.

    From my experience I don’t lose that much with diets other than atkins. I don’t binge eat protein with atkins, I follow the low calories diet while on atkins… I eat only protein rich and nutritious low carb food while still maintaining a lower calorie diet.

    What I realize with atkins is that… Yes it’s true. You do burn fat. I mean you do burn fat directly.

    While on atkins, I maintain an energy level equal or, I dare say, even greater than carb rich diets. My theory is that fat is constantly being burned that I actually have continuous energy being delivered to the bloodstream. It’s like a constant burning of fat and immediately using them.

    Note* I exercise with a regime similar to marathon training while on atkins and I never really felt the need to eat carbs to fuel me up.

  31. Robo Sapien says:

    The main reason that diets fail is because radical changes in nutritional intake incur uncomfortable shifts is physiology. If you are used to eating crap, then a dramatic change to healthy foods leads to a state of discomfort and a false notion that the “diet” is not working. The human body, by design, always takes the exact action required to survive the longest based on sensory input. Survival is its top priority, not comfort. Unfortunately, our bodies don’t think down the road about heart disease and such, it simply responds to what we are currently doing to it.

    It is also noteworthy that “overweight” is NOT synonymous with “unhealthy”. The only effective diet is the one our mothers told us: EAT YOUR DAMN VEGETABLES. Why? Human bodies cannot break strong molecular bonds, but plants can. Plants break tightly bonded nutrient molecules apart, therefore we eat the plants and we get those nutrients in a useable form.

    Everything we do at a cellular level produces acids as a byproduct. Weak acids are expelled through the lungs in the form of CO2. The body needs minerals to buffer strong acids which cannot be expelled this way. These acids MUST be buffered so that they do not damage sensitive tissue on their way out. Many of these stronger acids are a result of eating excess protein, which has a negative energy impact from intake beyond the threshold of bodily need. That means we use up more resources trying to get rid of what we don’t need than we get from eating them in the first place.

    So what happens when the body’s natural mineral reserves run out? If we don’t get enough natural sodium and minerals from vegetables, then the body starts taking useable buffers from other places, namely the bones. Osteoperosis, anyone? We’ve all heard the story of the little old lady who fell and broke her hip. The truth is, the bones of her hip, porous from being robbed of calcium over the course of years, gave way under the pressure of supporting her body weight and broke, causing her to fall.

    We evolved eating diversely, so all-vegetarian diets are not without their problems, but raw veggies should be your primary intake, at least 60% — achieve the vegetable discipline, and you will not overeat. You won’t get hunger signals from your body if you are giving it what it really needs.