A Possible Metabolic Advantage … But It Will Kill You

Two studies involving low-carb diets made headlines this week.  One suggested a low-carb diet may provide a metabolic advantage, while the other suggested a low-carb diet may kill you.

Let’s start with the good news:

Low-carb diet burns the most calories in small study

A new study is raising questions about the age-old belief that a calorie is a calorie.

The research finds that dieters who were trying to maintain their weight loss burned significantly more calories eating a low-carb diet than they did eating a low-fat diet.

The study, funded by the National Institutes of Health, was designed to see if changing the type of diet people consumed helped with weight maintenance because dieters often regain lost weight.

So scientists had 21 obese participants, ages 18 to 40, lose 10% to 15% of their initial body weight (about 30 pounds). After their weight had stabilized, each participant followed one of three different diets for four weeks. Participants were fed food that was prepared for them by diet experts. The dieters were admitted to the hospital four times for medical and metabolic testing.

The diets had the same number of calories, but the fat, protein and carbohydrate content varied. Those diets:

•A low-fat diet which was about 20% of calories from fat and emphasized whole-grain products and fruits and vegetables.

•A low-carb diet, similar to the Atkins diet, with only 10% of calories from carbohydrates. It emphasized fish, chicken, beef, eggs, cheese, some vegetables and fruits while eliminating foods such as breads, pasta, potatoes and starchy vegetables.

•A low-glycemic index diet, similar to a Mediterranean diet, made up of vegetables, fruit, beans, healthy fats (olive oil, nuts) and mostly healthy grains (old-fashioned oats, brown rice). These foods digest more slowly, helping to keep blood sugar and hormones stable after the meal.

Findings, published in this week’s Journal of the American Medical Association: Participants burned about 300 calories more a day on a low-carb diet than they did on a low-fat diet. “That’s the amount you’d burn off in an hour of moderate intensity physical activity without lifting a finger,” says senior author David Ludwig, director of the New Balance Foundation Obesity Prevention Center at Boston Children’s Hospital.

Now, before we all jump up and down and yell “Hallelujah!” we should keep in mind that a study population of 21 is pretty small.  The smaller the study population, the more likely a significant difference in the results is due to chance.  That’s just basic statistics.  If I flip a coin four times and it comes up heads three times, I can’t declare that my coin will come up heads 75% of the time.  My sample size was too small.  If it comes up heads 750 times out of a thousand, now we’re talking.

With that caveat out of the way, it was a controlled clinical study and does suggest a low-carb diet might provide a metabolic advantage.   That would certainly fit with my experience.  I always found it difficult to lose more than 10 pounds on a low-fat diet, and I had to put up with being hungry most of the time to achieve even that modest result.

I wasn’t hungry while losing weight on a low-carb diet, and this study hints at what I believe is the reason:  fuel availability.  If you burn more calories on a low-carb diet than on a low-fat diet, even at the same caloric intake, then your body is either storing less of what you eat or tapping more of what you’ve already stored.  Either way, your cells are getting more fuel, which means your body is less likely to slow your metabolism in response to what it considers a fuel shortage.

I think it’s significant that the dieters had already lost an average of 30 pounds before being divided into the three diet groups.  To keep your blood sugar within the biologically safe range, your body needs to switch between storing fatty acids when blood sugar goes up (so you’ll burn the excess glucose first), then releasing fatty acids as blood sugar goes down (so it doesn’t drop too low).

I believe what some people call a set point is related to our ability to release fatty acids at a rate sufficient to supply us with fuel when blood sugar begins to fall.  Obese people release as many fatty acids on average as non-obese people, but here’s the kicker:  they require more fat mass to do so.  Each unit of fat releases fewer fatty acids, so they need more body fat to release the same number of fatty acids as a thin person.  So at some point, shrinking the fat mass means releasing fewer fatty acids than the body needs to keep blood sugar stable.  That’s when the body rebels and slows down the metabolism (and ramps up hunger) instead of allowing the glucose/fatty-acid balancing act to go all out whack.

Obese people who’ve already lost 30 pounds are more likely to be approaching the point of biological rebellion than people who just started dieting.  That’s where the low-carb diet might provide a metabolic advantage.  By keeping insulin levels lower, the low-carb diet would enable a dieter’s shrinking fat mass to continue releasing fatty acids at the necessary rate.  No fuel shortage, no cellular-starvation response, no slowing of the metabolism.

Naturally, The Usual Suspects don’t agree:

George Bray, an obesity researcher at Pennington Biomedical Research Center in Baton Rouge who has also studied this topic and who wrote the accompanying editorial in JAMA, says that other studies “show that you can do well on any diet as long as you stick to it. Adherence is the major key for weight loss and maintenance. There is no magic in any diet.”

Fuel availability isn’t about magic, Dr. Bray.  It’s about biochemistry.

George Bray is what I’d call an intelligent imbecile. He’s been promoting high-carb and low-salt diets for years and plays games with his study designs and data to support his beliefs.  It was Bray, for example, who declared that macronutrient ratios make no difference for weight loss —  after he conducted a study in which protein and fat intake were altered, but carbohydrate intake stayed the same.  (Uh … wouldn’t you want to try messing with that variable too?)

It was also Bray who conducted the study of salt and hypertension that I mentioned in my Science For Smart People speech.  He put two groups of people on two different diets.  One diet was high in sugar and other junk, the other was more like a Mediterranean diet with lots of vegetables and no sugar.  Bray had each group consume a lot of salt with their diets for several weeks, then measured their blood pressure.  Then he had each group consume very little salt with their diets for several weeks and measured their blood pressure again.  Within each group, the average drop in blood pressure after severely restricting salt was slightly less than three points.  Whoopie.

That wasn’t the result Bray wanted, so in the study’s conclusions he compared blood pressure readings for the junk-food dieters after their high-salt phase to the blood pressure readings for the Mediterranean dieters after their low-salt phase, found a significant difference, and declared it evidence that salt causes high blood pressure.   That’s like comparing the livers of heavy drinkers who consume a lot of salt to the livers of moderate drinkers who consume very little salt and declaring that salt causes liver damage.

But enough about Bray.  There’s more bad science to dissect in the other study that hit the news this week:

‘Atkins’-Type Diets May Raise Risk of Heart Problems

Women who regularly eat a high-protein, low-carbohydrate diet may be raising their risk of heart disease and stroke by as much as 28 percent, a new study suggests.

Although the absolute increase in risk is small — four or five extra cases per 10,000 women — many young women try the Atkins diet or similar regimens and could be setting themselves up for cardiovascular problems later in life, the researchers noted.

“Low-carbohydrate, high-protein diets are frequently used for body-weight control,” said lead researcher Dr. Pagona Lagiou, assistant professor of epidemiology at the University of Athens Medical School in Greece. “Although [the diets] may be nutritionally acceptable if the protein is mainly of plant origin, such as nuts, and the reduction of carbohydrates applies mainly to simple and refined [carbohydrates] like unhealthy sweeteners, drinks and snacks, the general public does not always recognize and act on this guidance.”

That’s because we recognize the guidance as bull@#$%, Dr. Lagiou.  People weren’t living mainly on plant proteins back when rates of heart disease were much lower.

For the study, Lagiou’s team collected data on the diets of more than 43,000 Swedish women who were between the ages of 30 and 49 at the start of the study.

Over an average of 15 years of follow-up, there were more than 1,200 cardiovascular events, including heart disease and stroke. There were more of these events among the women who followed a high-protein, low-carbohydrate diet than among women who didn’t, the researchers found.

Compared with women who veered furthest from the high-protein, low-carbohydrate diet, women who followed the diet most closely increased their risk by 28 percent, even after other risk factors, such as smoking, drinking, hypertension, exercise and fat intake, were taken into account, the researchers noted.

I’m sure you’ve already spotted this study for what it is:  an observational study (strike one) based on food-recall questionnaires (strike two).  We don’t know if the participants accurately recalled what they’d been eating over the years (not likely), we don’t know what kinds of fats the so-called Atkins dieters consumed, and we don’t know if the people on the “high protein” diet ate a lot of meat because they believed it was good for them, or if they’re don’t-give-hoot types who believed red meat is bad for them but ate it anyway.  Those are two totally different types of people.  Since this study began 15 years ago, long before the low-carb/high-fat craze took off among health-conscious Swedes, I vote for the latter.

Another expert, Samantha Heller, an exercise physiologist and clinical nutrition coordinator at the Center for Cancer Care at Griffin Hospital in Derby, Conn., said “the results of this study are not surprising.”

Popular high-protein diets inevitably include an abundance of cheese and red and processed meats, and a dearth of healthy carbohydrates such as whole grains, vegetables, legumes and fruits, she said.

First off, Ms. Heller, the low-carb diets most advocates recommend aren’t “high-protein.”  They’re high-fat.  And secondly, why it is “inevitable” that those diets will include an abundance of cheese and processed meats?  I eat a bit of cheese and almost no processed meat whatsoever.  And if you believe whole grains are “healthy carbohydrates,” I suggest you read Wheat Belly.

Someone sent me a link to the full study, so I read it.  Here are some interesting numbers if we choose to assume (for no apparent reason) that the food-recall questionnaires were an accurate accounting of what people ate.

The researchers divided the women into groups based on carbohydrate and protein intake, but not fat intake.  So their scale went from high-carb/low-protein to low-carb/high-protein.  The researchers declared that the Atkins-type diet increased risk of heart disease and stroke, but the figures for strokes are laughable.  In the high-carb diet group, there were 3.1 ischemic (blood clot) strokes per 10,000 women.  In the high-protein group, there were 5.2 per 10,000 women.  So the actual difference (as I like to pound home in Science For Smart People) is 2.1 ischemic strokes for every 10,000 women.  If we take those odds and express them as percent, here’s what we get:

High-carb diet:  0.031%
High-protein diet:  0.052%

Yee-ikes, my Swedish lady friends.  (Yes, Katarina, I’m talking to you.)  Better lay off the “high-protein” foods.  Your absolute odds of an ischemic stroke will go up by two one-hundredths of one percent.  Oh, and your absolute odds of a hemorrhagic (vessel-bursting) stroke will also go up by one one-thousandth of one percent, according to the study data.  Expressed as the relative risk that researchers love to toss around, that’s a 12% increase (0.9 per 10,000 vs. 0.8 per 10,000), so I’d be worried if I were you.

Since the headlines were about the increase in risk for heart disease, let’s look at those numbers.  In the high-carb group, there were 8.4 cases of heart disease per 10,000 women.  In the high-protein group, there were 12.6 cases per 10,000 women.  So expressing the odds as percentages:

High-carb diet:  0.084%
High-protein diet:  0.126%

Even if you accept that the food-recall questionnaires were accurate, that the “high-protein” diet was actually an “Atkins-like” diet (not just people eating a lot of processed meat), and that these figures are actually telling us something about cause and effect (which an observational study cannot do), we’re looking at an absolute difference in the odds of about four one-hundredths of one percent.

In order to stay lean and continue feeling strong and energetic, I’ll roll the dice and take those odds.  I have a feeling I can beat them.


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122 thoughts on “A Possible Metabolic Advantage … But It Will Kill You

  1. Carolyn Gillham

    How many women were on birth control pills (or other hormonal meds) and what were their daily stress levels and sleep patterns?

    No idea. Those questions may not have been asked in the survey.

    Reply
  2. Trina

    Hi Tom, I’ve been following your blog since I watched FatHead (which was excellent by the way).

    I just read the following article this week http://www.theglobeandmail.com/life/health-and-fitness/health/how-to-keep-the-pounds-off-with-the-right-diet/article4371808/ and made note of their “warnings” about low carb (which I’ve been doing since Feb of this year – lost 32 pounds so far). Did you read this information in the study and what are your thoughts?

    “While the very low-carbohydrate diet did the best job at preserving a participant’s resting energy expenditure, it had potentially harmful effects. Levels of cortisol, a stress hormone, were highest with this diet. Higher cortisol levels may promote fat storage and impair the body’s ability to use insulin, the hormone that regulates blood sugar.

    C-reactive protein, an inflammatory chemical, was also higher on the very low-carbohydrate diet. Ongoing low-grade inflammation contributes to many diseases, including heart disease, stroke, diabetes and Alzheimer’s.

    The findings suggest that the best diet strategy to maintain a weight loss is to cut the glycemic load of your diet rather than its fat content. The low-glycemic diet had similar, although smaller, metabolic benefits to the very low-carbohydrate diet but without the adverse effects on stress and inflammation.”

    The low-carb diet didn’t raise C-reactive protein levels. It lowered them slightly less than the other diets. Cortisol did go up a bit; my wild-@$$ guess is that it was related to the need for gluconeogensis — making glucose out of protein. Perhaps that would go down as the dieters become keto-adapted over time and rely less on glucose for brain fuel. I’d worry less about a minor rise in cortisol than a plunge in metabolism, which is what the low-fat dieters experienced.

    Reply
  3. Justin B

    Sadly, as long as one of these bogus studies hits the headlines at least once a month, it will maintain the general consensus religious belief that it is true. That’s all the USDA and pharmaceutical companies have at this point: hammer the untruth into people’s heads to keep it second-nature, so those people don’t even think to bring science into it.

    And most of the time we see a “meat kills!” headline, it’s based on an observational study.

    Reply
  4. Chris

    I am better for getting rid of sugar and flour and grains. My weight is down 40lbs…and my cholesterol went from 289…to 214..hdl was 34..now its’45.

    My doc was happy, BUT he was concerned I was eating too much fat!!!! Diet is like religion and politics..there is NO changing anyone’s mind.

    My vegan family and friends are sort of PISSED that I lost weight this way!

    It’s a cliche, but the best we can do is Be the Change…and rub in their face! 🙂

    A friend of mine experienced a major improvement in his lipid profile on the Atkins diet. His doctor’s attitude was something like, “Okay, if it’s working, keep doing it … but don’t tell me about it.”

    Reply
  5. Tyler

    @Lissa:

    The median carb intake was 200g a day. Even the tenth decile was still at 124 or so.

    I’d love to know what source those carbs came from too, but in my experience, it’s probably not just vegetables if it’s 200g a day. I’m not even sure I could eat that many carbs in the form of vegetables, or even with some added fruit, and I’m a big guy and can eat quite a bit. So take from that what you will.

    You’d have to graze on vegetables all day to get 200 carbs, unless you start tossing in the starchy variety.

    Reply
  6. Lissa

    I read somewhere that their idea of “low carb” was still somewhere north of 200 grams a day … and no telling what kind of carbs those were, whether grain, sugar, fruit or what.

    Reply
  7. Bruce

    Regarding the belief that low carb dieters eat almost no vegetables. I just came back from a just opened Chinese buffet in town. I know, Chinese food is not usually low carb, but, not only do they have the usual heavy sauced foods, they also have sushi, and best of all, a pick out your own fresh veg and sliced meat. Put it on a plate. Hand it to a guy who cooks it on a flat top with a little oil. Your choice of teriaki sauce (NO) or hot sauce (Yes, on one of the plates). I had two plates of sliced beef, shrimp, red pepper, mushroom, jalapeno, zucchini, those little ears of corn, sprouts, and egg. No rice. No noodles. All for 7 bucks.

    Try to beat that with a Subway sammich.

    Not bad for the price.

    Reply
  8. Stacie

    What I find very telling is the fact that “they” keep pumping out studies to prove their point. Why the need to keep proving something it it is already supposedly true. The same can be said for the statin trials. They continue to talk about meta-analyses, etc. in order to prove their point,20 years after the fact. I think “they” are getting really nervous because the cat is out of the bag!! Too many people have too much money to lose.

    I think you’re exactly right. And they’ll keep trotting out these lousy observational studies because the clinical studies aren’t working in their favor.

    Reply
  9. Lori

    I’m glad others read these studies so I don’t have to. A diet rich in bird seed and paint oil doesn’t make any sense, straight out of the box.

    Reply
  10. Steve

    But but but but Tom, low carb will kill you! Haven’t you seen all of the headlines and news reporters talking about the dangers of low carb! You know those DANGERS right, right?! Im sure I’ve seen someone dying on low carb somewhere! I mean, can’t you see how starving yourself okay nutrient depleting low fat diet is better for you, especially with heart healthy whole grains!

    Yeah, I expect to keel over any day now.

    Reply
  11. Marilyn

    Tom replied: “The rep of course replied that dogs need carbohydrates for energy.”

    That must be why your two grainless canines are so weak and lethargic?????

    Oh yeah, I had a good chuckle over that one. Our rotties are definitely not running short on energy.

    Reply
  12. Marilyn

    “. . .healthy carbohydrates such as whole grains, vegetables, legumes and fruits . . .” It’s as if these people get to a certain point, and then their brains go on “autofill” and they spout exactly the same words every time.

    Yeah, it’s like pushing the play button on a recorded message.

    Reply
  13. charles

    http://anthonycolpo.com/?p=3680

    Finally, a Study that Proves a Low-Carb Metabolic Advantage? Yeah, Right

    NO TIGHTLY CONTROLLED STUDY IN THE HISTORY OF HUMANKIND HAS EVER SHOWN GREATER FAT LOSS ON A TRULY ISOCALORIC LOW-CARB DIET.

    CRP (C-reactive protein) tends to be elevated during inflammatory states such as illness and infection. While CRP was lower on all three diets compared to the pre-weight loss baseline, it remained highest on the low-carb diet (CRP levels were almost identical during the low-fat and low-GI diets).

    For the three diets, cortisol excretion measured via 24-hour urine collection was 50 μg/d for low fat, 60 μg/d for low glycemic index; and 71 μg/d for very low carbohydrate. This adds to the numerous other studies showing carbohydrate restriction to increase cortisol levels (I’ve written about this here).

    So what we appear to have here, folks, is a metabolic milieu during the low-carb diet that indicated a more catabolic and inflammatory state.

    In other words, in the subjects that did experience lower declines in REE and TEE during the low-carb phase, the culprit may have been increased catabolism. If so, the lower drop in EE was not necessarily a good thing – it may have in fact been reflective of harmful rather than beneficial processes occurring in the body.

    Anthony’s “tightly controlled” studies were of semi-starvation diets of around 800 calories. As I’ve written before, I expect a metabolic advantage (if there is one) to show up at higher calorie levels, not levels so low that even a “high carb” diet translates to 100 grams per day or less. I saw a study recently of 1800-calorie diets with different macronutrient ratios. The low-carb group lost the most body fat by a wide margin.

    Reply
  14. Christopher

    Gotta tell you, my head hurts from a good helping of head-banging on the table. I work at a steak-house, and as such eat plenty of meals there, since I get half off menu items. My normal meal consists of a salad from our salad bar, with ham chunks in it, and a nice, juicy, half-pound Chopped Steak with onions. While eating a meal recently, one of my coworkers seemed to feel the need to ask why I was, in her words, ‘destroying my body by eating all that meat.’ So, I just responded in the simplest way I knew how. I told her that I didn’t buy into all the Government Guidelines. When she asked why, I told her simply because I took Biology in highschool. This is where the head-banging begins. My coworker asked me, and I quote-

    “What does biology have to do with nutrition or being healthy?”

    I didn’t even bother with the conversation after that. I was just stunned speechless. Especially since she and I were in the same biology class at the time. This girl got better grades than I did, and she actually felt the need to ask what biology had to do with nutrition, like the two studies were unrelated. I’ve heard a lot of strange things before on this topic, but that really takes the cake for me. How about you?

    That’s priceless.

    Reply
  15. Marilyn

    Just for kicks, I googled “healthy whole grains, fruits and vegetables” in quotes and got over 31,000 hits for that combination of words, the first two for DOG FOOD!

    Chareva talked to a dog-food representative at a store once. She said she wasn’t interested in dog foods that contain grains. The rep of course replied that dogs need carbohydrates for energy.

    Reply
  16. AndreaLynnette

    Maybe those rises in cortisol have to do with the stress of arguing with friends, family, doctors, coworkers, the check-out lady in the grocery store, and total strangers who think they have the right to lecture you on all the bacon, cheese, butter, coconut milk, coconut cream, and whipping cream you buy.

    Even if, BIG FREAKIN’ IF, this super low carbohydrate diet DOES raise my cortisol a tiny bit, I really don’t care. The extra weight, the blood sugar yo-yo, the chronic pain, the inability to walk very long, let alone RUN is way worse than any potential teeny little rise in cortisol. Losing the pain, the weight, the illness, without suffering constant hunger and fatigue, without wearing my life away on a treadmill, IS TOTALLY WORTH THE RISK.
    The risk/reward analysis is, to me, like being unwilling to drive or ride in a car for fear that an albatross will fly into your windshield, causing you/the driver to lose control of the vehicle, plummet down into an arroyo, at the bottom of which the car will burst into flames and you will perish in the fire.

    I totally agree.

    Reply
  17. Ari

    Tom, you wrote:

    I eat a bit of cheese and no almost processed meat whatsoever.

    How do you know if the meat you eat was almost processed or not? Just because the meat is not processed doesn’t mean that somebody wasn’t about to process it and just decided not to.

    I almost agree with you. I’ll fix the switched words, thanks.

    Reply
  18. Drew @ Willpower Is For Fat People

    Tom, Tom, Tom … [shakes head] You clearly don’t understand statistics. I know you follow politics, so let me put this in terms you’ll understand.

    When something is wrong with the country, say unemployment is too high, the TV pundits say, “Our rate of job creation is slower than our population growth. We are effectively losing jobs every day.”

    Someone from Party A will say, “My plan will slow the rate of loss by ten percent.”

    Someone from Party B will say, “Well my plan will slow the rate of loss by twenty percent.”

    The pundits will say, “Party B has a plan to increase employment twice as fast as Party A.”

    See? That’s just good math.

    Indeed. If a program was scheduled to increase by 10% and Congress reduces the increase to 5% instead, that’s a “cut in spending” in D.C.

    Reply
  19. AndreaLynnette

    I’m really, really grateful to people like you who willingly wade through these piles of bovine excrement so I don’t have to. I’m supposed to STOP eating LCHF because of a 0.05% increase in risk, but I SHOULD take scads of medicines with 30-70% risk of side effects instead?! ARGH!

    Excuse me, I’m going to go drink a coconut milk/heavy cream protein shake and eat some bacon.

    Give a toast in my honor when you drink that shake.

    Reply
  20. Heather

    This was covered by the daily express:

    http://www.express.co.uk/posts/view/329161/Heart-attack-risk-in-dieting

    LOL:

    ‘Cutting daily carbohydrate intake by just 20g, equivalent to a small bread roll, and increasing protein by 5g, or one boiled egg, increased the risk of cardiovascular disease by five per cent.
    But when the diet is followed to excess, the chances of heart disease, stroke or narrowed arteries soared by 60 per cent, it was claimed.’

    an extra LOL for emphasis.

    Head. Bang. On. Desk.

    Reply
  21. Dorian

    In the first study, I found it interesting that they defined the “Low-Glycemic Index Diet” as having a “moderate glycemic load”, while they defined the “Very Low-Carbohydrate Diet” as having a “low glycemic load”.

    Why would the “Low-Glycemic Index Diet” not have the lowest glycemic load of all three diets?

    Here’s how it’s presented in the study:

    1. low-fat diet
    (60% of energy from carbohydrate, 20% from fat, 20% from protein; high glycemic load),

    2. low–glycemic index diet
    (40% from carbohydrate, 40% from fat, and 20% from protein; moderate glycemic load), and

    3.very low-carbohydrate diet
    (10% from carbohydrate, 60% from fat, and 30% from protein; low glycemic load)

    Seems like they could have titled #2 a Moderate Glycemic Index Diet or a Moderate Carbohydrate Diet.

    Table 1 was very interesting showing Carb grams/day for the three diets (310, 205, 50, respectively); showing Fat grams/day for Saturated, Monounsaturated, and Polyunsaturated; and Cholesterol mg/day (140, 280, 978, respectively).

    http://jama.jamanetwork.com/article.aspx?articleid=1199154

    Glycemic index is related to how quickly the carbs raise your blood sugar. Glycemic load is related more to the number of carbohydrates. So it’s possible to have a higher glycemic load while eating a lot of carbohydrates that are low on the glycemic index.

    Reply
  22. Tyler

    @Lissa:

    The median carb intake was 200g a day. Even the tenth decile was still at 124 or so.

    I’d love to know what source those carbs came from too, but in my experience, it’s probably not just vegetables if it’s 200g a day. I’m not even sure I could eat that many carbs in the form of vegetables, or even with some added fruit, and I’m a big guy and can eat quite a bit. So take from that what you will.

    You’d have to graze on vegetables all day to get 200 carbs, unless you start tossing in the starchy variety.

    Reply
  23. Bruce

    Regarding the belief that low carb dieters eat almost no vegetables. I just came back from a just opened Chinese buffet in town. I know, Chinese food is not usually low carb, but, not only do they have the usual heavy sauced foods, they also have sushi, and best of all, a pick out your own fresh veg and sliced meat. Put it on a plate. Hand it to a guy who cooks it on a flat top with a little oil. Your choice of teriaki sauce (NO) or hot sauce (Yes, on one of the plates). I had two plates of sliced beef, shrimp, red pepper, mushroom, jalapeno, zucchini, those little ears of corn, sprouts, and egg. No rice. No noodles. All for 7 bucks.

    Try to beat that with a Subway sammich.

    Not bad for the price.

    Reply
  24. Lori

    I’m glad others read these studies so I don’t have to. A diet rich in bird seed and paint oil doesn’t make any sense, straight out of the box.

    Reply
  25. Marilyn

    Tom replied: “The rep of course replied that dogs need carbohydrates for energy.”

    That must be why your two grainless canines are so weak and lethargic?????

    Oh yeah, I had a good chuckle over that one. Our rotties are definitely not running short on energy.

    Reply
  26. Christopher

    Gotta tell you, my head hurts from a good helping of head-banging on the table. I work at a steak-house, and as such eat plenty of meals there, since I get half off menu items. My normal meal consists of a salad from our salad bar, with ham chunks in it, and a nice, juicy, half-pound Chopped Steak with onions. While eating a meal recently, one of my coworkers seemed to feel the need to ask why I was, in her words, ‘destroying my body by eating all that meat.’ So, I just responded in the simplest way I knew how. I told her that I didn’t buy into all the Government Guidelines. When she asked why, I told her simply because I took Biology in highschool. This is where the head-banging begins. My coworker asked me, and I quote-

    “What does biology have to do with nutrition or being healthy?”

    I didn’t even bother with the conversation after that. I was just stunned speechless. Especially since she and I were in the same biology class at the time. This girl got better grades than I did, and she actually felt the need to ask what biology had to do with nutrition, like the two studies were unrelated. I’ve heard a lot of strange things before on this topic, but that really takes the cake for me. How about you?

    That’s priceless.

    Reply
  27. AndreaLynnette

    Maybe those rises in cortisol have to do with the stress of arguing with friends, family, doctors, coworkers, the check-out lady in the grocery store, and total strangers who think they have the right to lecture you on all the bacon, cheese, butter, coconut milk, coconut cream, and whipping cream you buy.

    Even if, BIG FREAKIN’ IF, this super low carbohydrate diet DOES raise my cortisol a tiny bit, I really don’t care. The extra weight, the blood sugar yo-yo, the chronic pain, the inability to walk very long, let alone RUN is way worse than any potential teeny little rise in cortisol. Losing the pain, the weight, the illness, without suffering constant hunger and fatigue, without wearing my life away on a treadmill, IS TOTALLY WORTH THE RISK.
    The risk/reward analysis is, to me, like being unwilling to drive or ride in a car for fear that an albatross will fly into your windshield, causing you/the driver to lose control of the vehicle, plummet down into an arroyo, at the bottom of which the car will burst into flames and you will perish in the fire.

    I totally agree.

    Reply
  28. Mark

    Hi Tom, I think this JAMA study is an excellent study (I’m a biostatistician by trade), and I’m a huge fan of Fat Head (but first time poster here).

    However, you wrote:

    “The smaller the study population, the more likely a significant difference in the results is due to chance. That’s just basic statistics.”

    I’m sorry to say that that isn’t really basic statistics and in fact it’s completely wrong. The alpha level (the pre-study type I error probability) is set by the researcher and has NOTHING to do with sample size. With type I error fixed, type II error (and power) depend on sample size. However, power is really irrelevant at the end of the study.

    Regarding your coin example, it’s not really a good analogy here. If you flip 3 out of 4 heads, then you can’t reject the null hypothesis that you’re using a balanced coin. However, if you flip 15 out of 20 heads, then you can reject the null hypothesis that you’ve got a fair coin (assuming that these are you first 20 flips and that you were looking for unfairness from the get go). Hope this makes sense.

    Thanks for clarifying. I’d best re-visit that topic.

    Reply
  29. Heather

    This was covered by the daily express:

    http://www.express.co.uk/posts/view/329161/Heart-attack-risk-in-dieting

    LOL:

    ‘Cutting daily carbohydrate intake by just 20g, equivalent to a small bread roll, and increasing protein by 5g, or one boiled egg, increased the risk of cardiovascular disease by five per cent.
    But when the diet is followed to excess, the chances of heart disease, stroke or narrowed arteries soared by 60 per cent, it was claimed.’

    an extra LOL for emphasis.

    Head. Bang. On. Desk.

    Reply
  30. Isabel

    I just wanted to mention that the CRP levels did not really rise with the low carb diet. They were just reduced less than with the other diets, but were still lower than the pre-weight loss baseline. These are the numbers provided by the study:

    Pre-weight loss baseline CRP: 1.75 (0.44 to 4.61)
    Low fat diet CRP: 0.78 (0.38 to 1.92)
    Low glycemic CRP: 0. 76 (0.50 to 2.20)
    Low carb: 0.87 (o.57 to 2.69)
    So, it is not accurate to say that the low carb diet “raised” CRP as some of the articles published on the media say. The levels are still lower than pre-weight loss, just not quite as low by a very very small difference (anything under 1 is considered normal CRP)
    Cortisol, however, did increase slightly. These are the numbers:
    Pre-weight loss baseline: 58 (47-73)
    Low fat: 50 (41-60)
    Low glycemic: 60 (49-73)
    Low carb: 71 (58-85)
    Normal range, by the way, is between 10 and 100.

    Reply
  31. Dorian

    In the first study, I found it interesting that they defined the “Low-Glycemic Index Diet” as having a “moderate glycemic load”, while they defined the “Very Low-Carbohydrate Diet” as having a “low glycemic load”.

    Why would the “Low-Glycemic Index Diet” not have the lowest glycemic load of all three diets?

    Here’s how it’s presented in the study:

    1. low-fat diet
    (60% of energy from carbohydrate, 20% from fat, 20% from protein; high glycemic load),

    2. low–glycemic index diet
    (40% from carbohydrate, 40% from fat, and 20% from protein; moderate glycemic load), and

    3.very low-carbohydrate diet
    (10% from carbohydrate, 60% from fat, and 30% from protein; low glycemic load)

    Seems like they could have titled #2 a Moderate Glycemic Index Diet or a Moderate Carbohydrate Diet.

    Table 1 was very interesting showing Carb grams/day for the three diets (310, 205, 50, respectively); showing Fat grams/day for Saturated, Monounsaturated, and Polyunsaturated; and Cholesterol mg/day (140, 280, 978, respectively).

    http://jama.jamanetwork.com/article.aspx?articleid=1199154

    Glycemic index is related to how quickly the carbs raise your blood sugar. Glycemic load is related more to the number of carbohydrates. So it’s possible to have a higher glycemic load while eating a lot of carbohydrates that are low on the glycemic index.

    Reply
  32. Exceptionally Brash

    Wow! That second study is truly a nightmare! It has seemed to cover just about every bad thing to to with a study. Perhaps I’ll use it as an interesting case study in future classes. At the very least, researchers need to move out of flatland and into considering ALL the macronutrients. As we all (should) know, a line is of lesser status than a triangle. A simplex plot should be in order.

    There’s no shortage of studies to use as examples of weak science.

    Reply
  33. Mark

    Hi Tom, I think this JAMA study is an excellent study (I’m a biostatistician by trade), and I’m a huge fan of Fat Head (but first time poster here).

    However, you wrote:

    “The smaller the study population, the more likely a significant difference in the results is due to chance. That’s just basic statistics.”

    I’m sorry to say that that isn’t really basic statistics and in fact it’s completely wrong. The alpha level (the pre-study type I error probability) is set by the researcher and has NOTHING to do with sample size. With type I error fixed, type II error (and power) depend on sample size. However, power is really irrelevant at the end of the study.

    Regarding your coin example, it’s not really a good analogy here. If you flip 3 out of 4 heads, then you can’t reject the null hypothesis that you’re using a balanced coin. However, if you flip 15 out of 20 heads, then you can reject the null hypothesis that you’ve got a fair coin (assuming that these are you first 20 flips and that you were looking for unfairness from the get go). Hope this makes sense.

    Thanks for clarifying. I’d best re-visit that topic.

    Reply
  34. Isabel

    I just wanted to mention that the CRP levels did not really rise with the low carb diet. They were just reduced less than with the other diets, but were still lower than the pre-weight loss baseline. These are the numbers provided by the study:

    Pre-weight loss baseline CRP: 1.75 (0.44 to 4.61)
    Low fat diet CRP: 0.78 (0.38 to 1.92)
    Low glycemic CRP: 0. 76 (0.50 to 2.20)
    Low carb: 0.87 (o.57 to 2.69)
    So, it is not accurate to say that the low carb diet “raised” CRP as some of the articles published on the media say. The levels are still lower than pre-weight loss, just not quite as low by a very very small difference (anything under 1 is considered normal CRP)
    Cortisol, however, did increase slightly. These are the numbers:
    Pre-weight loss baseline: 58 (47-73)
    Low fat: 50 (41-60)
    Low glycemic: 60 (49-73)
    Low carb: 71 (58-85)
    Normal range, by the way, is between 10 and 100.

    Reply
  35. Exceptionally Brash

    Wow! That second study is truly a nightmare! It has seemed to cover just about every bad thing to to with a study. Perhaps I’ll use it as an interesting case study in future classes. At the very least, researchers need to move out of flatland and into considering ALL the macronutrients. As we all (should) know, a line is of lesser status than a triangle. A simplex plot should be in order.

    There’s no shortage of studies to use as examples of weak science.

    Reply
  36. SB

    “The smaller the study population, the more likely a significant difference in the results is due to chance. That’s just basic statistics.”
    This is incorrect because you are ignoring confidence intervals. If sample sizes are small, the confidence intervals are large, so a statistically significant difference must imply a large effect. Large sample sizes on the other hand can suggest that small differences (clinically insignificant) are statistically significant. Didn’t you go over this part in your science for smart people video?

    As I understood it, all other factors being equal, the smaller the study population the more likely the results are due to chance. In other words, we may have statistically significant results with 21 people, but the odds of those results being due to chance would still be much lower if our study population was 210.

    Reply
  37. SB

    “The smaller the study population, the more likely a significant difference in the results is due to chance. That’s just basic statistics.”
    This is incorrect because you are ignoring confidence intervals. If sample sizes are small, the confidence intervals are large, so a statistically significant difference must imply a large effect. Large sample sizes on the other hand can suggest that small differences (clinically insignificant) are statistically significant. Didn’t you go over this part in your science for smart people video?

    As I understood it, all other factors being equal, the smaller the study population the more likely the results are due to chance. In other words, we may have statistically significant results with 21 people, but the odds of those results being due to chance would still be much lower if our study population was 210.

    Reply
  38. Ailu

    Speaking of dog food… I’ve made my own dog food ever since I brought home our new puppy over 2 years ago. Our old dog, who subsisted on canned food before that never looked back, but the puppy doesn’t quite appreciate it as much because he never had the bad stuff. However, as I can’t afford to feed nearly 100% protien, I do cut it with some rice. Both are very healthy with nice shiney coats. The older dog’s health esp. improved, she had a digestive disorder that has never returned since. Here’s the recipe I use:

    5-6 lbs ground meat
    1-2 lbs organ meat (beef or chicken livers, gizzards, heart, kidney, etc; I change it up each time)
    1 large bag frozen spinach
    1 can pumpkin
    3 cups cooked brown rice
    1 tbsp calcium carbonate
    4 Fish oil capsules

    I do cook the meat, as I just can’t afford to feed them sushi-grade beef. Aside from this, I buy butchered bones with marrow and throw them around the yard as chewies. Just wish I’d stop stepping on them. Ouch. lol

    Dogs certainly don’t need rice, but I’d feed them rice before wheat any day.

    Reply
  39. David

    As you talked about salt, my mom apparently believes that plain popcorn is healthy and her friend that thinks low fat and carbs are good decided to have some at the movies. The friend ate it and complained that the “salt is going to drive her weight up” after having a stomach ache. I told them it was the popcorn and not the salt and even Atkins would agree. The response was “that is your opinion! Popcorn is healthy and only bad for a diabetic! You can believe everything Atkins said, but low fat and weight watchers work because my friend lost weight doing that diet and kept her weight off.”

    Some people do lose weight on Weight Watchers and keep it off. Their success rate isn’t good, but name any diet and it works for someone.

    Reply
  40. Ailu

    Speaking of dog food… I’ve made my own dog food ever since I brought home our new puppy over 2 years ago. Our old dog, who subsisted on canned food before that never looked back, but the puppy doesn’t quite appreciate it as much because he never had the bad stuff. However, as I can’t afford to feed nearly 100% protien, I do cut it with some rice. Both are very healthy with nice shiney coats. The older dog’s health esp. improved, she had a digestive disorder that has never returned since. Here’s the recipe I use:

    5-6 lbs ground meat
    1-2 lbs organ meat (beef or chicken livers, gizzards, heart, kidney, etc; I change it up each time)
    1 large bag frozen spinach
    1 can pumpkin
    3 cups cooked brown rice
    1 tbsp calcium carbonate
    4 Fish oil capsules

    I do cook the meat, as I just can’t afford to feed them sushi-grade beef. Aside from this, I buy butchered bones with marrow and throw them around the yard as chewies. Just wish I’d stop stepping on them. Ouch. lol

    Dogs certainly don’t need rice, but I’d feed them rice before wheat any day.

    Reply
  41. David

    As you talked about salt, my mom apparently believes that plain popcorn is healthy and her friend that thinks low fat and carbs are good decided to have some at the movies. The friend ate it and complained that the “salt is going to drive her weight up” after having a stomach ache. I told them it was the popcorn and not the salt and even Atkins would agree. The response was “that is your opinion! Popcorn is healthy and only bad for a diabetic! You can believe everything Atkins said, but low fat and weight watchers work because my friend lost weight doing that diet and kept her weight off.”

    Some people do lose weight on Weight Watchers and keep it off. Their success rate isn’t good, but name any diet and it works for someone.

    Reply
  42. Per Wikholm

    Hello Tom!
    Sorry for not commenting on this for a few days. Me, Katarina and the kids have been out for a few days on an wonderful LCHF camping event in a remote area outside the small town of Säffle with quite poor internet access. But here we go…

    This Swedish study made on females in our hometown of Uppsala has made a lot of headlines in Sweden too. But it is not about the Atkins diet or the LCHF diet. Basically no Swede had heard about the Atkins diet in 1991-1992 when this SINGLE food-recall questionnaire was sent out. The now popular LCHF concept was invented in late 2005 – about the time the study ended.

    In 1991-1992 no one were eating anything that could be called low carb in Uppsala, Sweden. Those who ate somewhat more protein then the others probably ate more frequently at McDonalds (and smoked more, exersized less et c).

    But actually we have some Swedes that have been on a low carb, high protein diet for thousands of years – the aboriginal Sami people with a diet of fat fish like salmon, reindeer meat and organs, small quantities of vegetables and some berries. Turns out they did not suffer as much cardiovascular disease as the rest of the Swedes… so what do we have here? I new paradox! The Sami paradox.

    That has to be explained away by conventional wisdom. And now finally we have a thesis trying to do just that. The well documented good health of the Sami people had absolutely nothing to do with their diet… it must have been some other factor.

    Here is the thesis [Sami lifestyle and health: epidemiological studies from northern Sweden] available for free, full text download.

    http://umu.diva-portal.org/smash/record.jsf?pid=diva2:489385&searchId=null&rvn=1

    Best regards Per & Katarina Wikholm

    That list of paradoxes is getting quite lengthy.

    Sounds like an excellent camping trip. Say hey to Katarina for me.

    Reply
  43. Galina L.

    @Ailu,
    It looks like that white rice contains no anti-nutrients unlike the brown one, it is just a pure starch and will cause even less damage to dog’s GI tract . I also advice you to ask around butchers. They routinely trim pricey steaks from an extra fat and put it in a garbage. Probably, you will have to be more persuasive than just ask and run away. They started to give me fat for free after I complained about their ground beef being too lean. I have a manual meat grinder. Most of the time such cut-offs contain some meat.

    Reply
  44. Per Wikholm

    Hello Tom!
    Sorry for not commenting on this for a few days. Me, Katarina and the kids have been out for a few days on an wonderful LCHF camping event in a remote area outside the small town of Säffle with quite poor internet access. But here we go…

    This Swedish study made on females in our hometown of Uppsala has made a lot of headlines in Sweden too. But it is not about the Atkins diet or the LCHF diet. Basically no Swede had heard about the Atkins diet in 1991-1992 when this SINGLE food-recall questionnaire was sent out. The now popular LCHF concept was invented in late 2005 – about the time the study ended.

    In 1991-1992 no one were eating anything that could be called low carb in Uppsala, Sweden. Those who ate somewhat more protein then the others probably ate more frequently at McDonalds (and smoked more, exersized less et c).

    But actually we have some Swedes that have been on a low carb, high protein diet for thousands of years – the aboriginal Sami people with a diet of fat fish like salmon, reindeer meat and organs, small quantities of vegetables and some berries. Turns out they did not suffer as much cardiovascular disease as the rest of the Swedes… so what do we have here? I new paradox! The Sami paradox.

    That has to be explained away by conventional wisdom. And now finally we have a thesis trying to do just that. The well documented good health of the Sami people had absolutely nothing to do with their diet… it must have been some other factor.

    Here is the thesis [Sami lifestyle and health: epidemiological studies from northern Sweden] available for free, full text download.

    http://umu.diva-portal.org/smash/record.jsf?pid=diva2:489385&searchId=null&rvn=1

    Best regards Per & Katarina Wikholm

    That list of paradoxes is getting quite lengthy.

    Sounds like an excellent camping trip. Say hey to Katarina for me.

    Reply
  45. Galina L.

    @Ailu,
    It looks like that white rice contains no anti-nutrients unlike the brown one, it is just a pure starch and will cause even less damage to dog’s GI tract . I also advice you to ask around butchers. They routinely trim pricey steaks from an extra fat and put it in a garbage. Probably, you will have to be more persuasive than just ask and run away. They started to give me fat for free after I complained about their ground beef being too lean. I have a manual meat grinder. Most of the time such cut-offs contain some meat.

    Reply
  46. Jim

    Number Needed to Treat

    NNT = 1/(Absolute Rate Difference)

    Stroke Incidence

    High-carb diet: 0.031%
    High-protein diet: 0.052%
    Absolute Rate Difference 0.021% (0.00021)
    Number Needed to Treat NNT 4,762
    Number of people receiving no benefit 4,761

    Not a very effective treatment.

    CHD Incidence

    High-carb diet: 0.084%
    High-protein diet: 0.126%
    Absolute Rate Difference 0.042% (0.00042)
    Number Needed to Treat NNT 2,981
    Number of people receiving no benefit 2980

    Not a very effective treatment.
    ——————————————

    I think it is always worth the small effort to take the extra steps to show how many participants are needed to actually prevent one negative outcome.

    It also shows how many “mistakes” or “cheats” or “tricks” or “tweaks” are needed to torture the data to show the point that you want to make.

    Just a few “data tweaks” will produce this claimed “benefit”.

    If you remember the “Processed Meat Study” of a few months ago, the NNT was as high as about 30,000 or so.

    If you don’t take the opportunity to keep hammering away at the use of the NNT concept, you are missing a great educational opportunity.

    To many people won’t even pick up the damned calculator, or if they do they stop just a few keystrokes from producing a highly illuminating number that is a nice big easily visualized thing, not a tiny little decimal number that is harder to digest.

    The large number of people who get no benefit is also pretty nice to see.

    Agreed. That’s a good number to toss into the analysis.

    Reply
  47. Jim

    Number Needed to Treat

    NNT = 1/(Absolute Rate Difference)

    Stroke Incidence

    High-carb diet: 0.031%
    High-protein diet: 0.052%
    Absolute Rate Difference 0.021% (0.00021)
    Number Needed to Treat NNT 4,762
    Number of people receiving no benefit 4,761

    Not a very effective treatment.

    CHD Incidence

    High-carb diet: 0.084%
    High-protein diet: 0.126%
    Absolute Rate Difference 0.042% (0.00042)
    Number Needed to Treat NNT 2,981
    Number of people receiving no benefit 2980

    Not a very effective treatment.
    ——————————————

    I think it is always worth the small effort to take the extra steps to show how many participants are needed to actually prevent one negative outcome.

    It also shows how many “mistakes” or “cheats” or “tricks” or “tweaks” are needed to torture the data to show the point that you want to make.

    Just a few “data tweaks” will produce this claimed “benefit”.

    If you remember the “Processed Meat Study” of a few months ago, the NNT was as high as about 30,000 or so.

    If you don’t take the opportunity to keep hammering away at the use of the NNT concept, you are missing a great educational opportunity.

    To many people won’t even pick up the damned calculator, or if they do they stop just a few keystrokes from producing a highly illuminating number that is a nice big easily visualized thing, not a tiny little decimal number that is harder to digest.

    The large number of people who get no benefit is also pretty nice to see.

    Agreed. That’s a good number to toss into the analysis.

    Reply

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