More Controversy!

Here's Blakes analysis of the LA Times article I put in my last post. How are we to know what to think?:


Hey Tess... here's one of the articles alluded to in the LA times column. It's pretty interesting to look. You're probably not interested in these details, though, and if not I'm sorry, but that's where the devil is. It shows how much each study has to be stared at to make sense, and how hard it can be to make sense of unrelated studies.

I guess if nothing else, as a friend, this shows you what a drag it is to be me.

Don't bother to read on if you don't want to see my analysis...

First, the study includes a total of 40 people. That is a very small number.

Second, it's important to segregate what they say about weight loss, fats circulating in the blood, and actual adipose tissue.

The weight before was about 210 pounds (plus/minus 20 pounds) for both grups. The high fat diet end weight was 190 (plus/minus 20 pounds) while the carb diet end weight was 195 (plus/minus 20 pounds). So, really, this study isn't making a claim about weight; the errors make the differences between and before/after indistinguishable. A better number to report would probably have been the % weight loss. This might wash out the big errors (comparing someone that was 170 with someone 210 won't reveal how each individual fared). Of course, this may have looked even worse than body mass.

The body fat was actually less in the high carb group.... 36.8% vs 38.2%... though the size of their error bars (8%) actually dwarfs any difference. The carb group had more non-fat body mass, which makes them slightly heavier overall.

Where they do see something striking is in concentrations of blood lipids. A decrease in triacylglycerols of 50% (as he said in the article). The carb group also saw a decrease of 20% (not mentioned in the article), which is also really striking. The error bars in both these numbers is 25%. Caloric reduction in general is a good thing for diabetes risk.

The other thing that's striking is the shift in the insulin response. This gets to that homeostasis thing I was mentioning before... the reduced carbohydrate load allows the body to shift to a lower insulin response: there's less sugar to import, so we require a smaller insulin response. On the other hand, the difference is response is really not too surprising: the body responds to the stimulus... less carbs, less insulin required to move fewer carbs into the cell. I bet if they looked after week1 of the study, they'd have seen the same thing.

To be fair, I think the metrics of diabetes risk is what they're emphasizing (circulating lipids). So, you can still be overweight (if I lose 20 pounds, I'll still be overweight), but reduce your risk for diabetes. Which is more important? I don't know. Being overweight but diabetes free is still probably linked to self-esteem and depression issues.

So, I guess the bottom line is that it's easy to confuse weight loss and health benefits. Also, such small studies are very hard to interpret because the errors are so large. However, it is nice to know that, even if you're too fat (at 210 myself, I can say that's too fat), you can still avoid risk for diabetes!

In the end, for me, the article is about how 210 pound people go on 2000 calorie diets for 12 weeks. I wish I could do that with a house full of pumpkin pies, candied yams, mashed potatoes, fudge and rolls.

Anyway, sorry! But thanks for posting the link, it was useful and fun for me!

bg

We Have a Controversy!

My friend Blake had the following to say about carbs and cholesterol. I'm hoping he'll read the Taubes book and help us all make sense of it!

"Hey Tess, this is obviously unsolicited, so sorry and feel free to ignore. I do teach metabolism, and have thought a bit about all this, not that I'm positioning myself as an Authority. But reading your post, well it made me think. What I will say overall is that its really hard for *anyone* to look at the nutritional science of the past 10, 20, 30 years and come up with definitive conclusions. I'm pretty suspicious of attempts to do so, though obviously an Answer is what everyone is after. Not that scientists are the only ones who can/should interpret the science, either...
Anyway, as to insulin:
Insulin's job is not to store fat. Its job is really to respond to sugar concentrations in the blood, and one of its principal duties is to induce import of glucose into the cell. When there's a dietary influx of carbohydrates (like the chocolate chip cookies I've been working through), that's a signal that the 'fuel level' is high, and it's time to store it away for future use. On the one hand, insulin induces storage of carbohydrates as glycogen (particularly in the liver). On the other hand, when glycogen levels are adequate, insulin stimulation leads to synthesis of lipids. This is the trouble! Excess carbohydrate is going to be stored as fat... the simplest-to-grasp reason is that, calorie-for-calorie, fat takes up less space... fat doesn't have to be bathed in water, like carbohydrate polymers such as glyogen do... for this and other reasons, fat is a better energy storage medium. Also, the liver has limited glycogen storage capacity, whereas we have lots of adipocytes for storing fat distributed all over the body. There are other effects of insulin on gene expression, etc... In the end, insulin is part of a 'homeostasis system' that works to keep energy levels constant. Incidentally, that tendency towards homeostasis makes it hard to lose the weight we've gained.
So insulin is good! Import of carbohydrates is good! Storage of glycogen and lipids is good! Loss of sensitivity to insulin (and the resulting health problems including perhaps obesity and CHD) is most likely the result of difficulties that arise from chronic overingestion of calories (of carbohydrates perhaps most specifically, but of food in general) and concomitant underconsumption (use of) those calories in exercise.
As for the Western diet, I just wanted to say that indigenous American and Asian diets are not lacking in carbohydrates: those non-western cultures gave us corn and rice, after all! Again, my impression is that it's this over/under problem that leads to issues of obesity, and thence to the other problems... As for the refined carbohydrate thing, I tend to think of it like I do the high-fructose corn syrup thing. Fructose is fructose - it all goes into the same energy production pathway - the problem is the amount of it we ingest. All plant fuel storage carbohydrates are made of glucose, and glucose is what insulin causes to be imported into the cell, whether the grain has had the bran removed or not. We just need to eat less of them to avoid storing them as fats.
I guess I just wanted point out that it's not carbohydrates per se that lead to insulin dysfunction, but overconsumption of these and other foods. Our lives depend on carbohydrates. Too, I think (having not read the book) that statement about 'everything we believe about a healthy diet is wrong' could be a bit hyperbolic. What's really problematic, I tend to think, is the search for a diet 'Answer' other than moderate eating and exercise (this, from a fat, lazy hedonist).
The books may have covered all this stuff, and I'm just being a didact (in fact, I know I'm a didact, so f@$& me!). I have enjoyed your blog... and the Taube book's in our library, so I'll check it out... I hope you don't mind my note, though, and I won't mind if you tell me to piss off! I totally respect your quest... my own quest focuses on finding time to do anything resembling exercise. Hopefully you take or leave my input without getting to irritated with me!"

Meanwhile, here's an article from the LA Times that summarizes what I've read better than I ever could:

http://www.latimes.com/health/la-he-carbs-20101220,0,5464425.story

My Primal Inspiration

Here's a link to my friend Holly's blog: http://www.underdogdesign.net/wordpress/2010/09/10/an-archaeologist-goes-primal/
Also see her next post: Primal in Paris.
She's been on the low carb primal path for awhile and has more to say than I do, plus she's a more sophisticated writer, so you might enjoy checking out her blog as well.
Cheers!

Carbs are Bad

If you have ever tried to lose weight by counting calories or simply by eating less and exercising more, or if you have ever tried to lower your cholesterol by lowering your fat intake, or even if you have just wondered how the food you eat affects your health, boy do I have a reading list for you. These books were so compelling that I had to sign back in to Skinnymamasdontdiet for yet another round.

First of all, "Good Calories, Bad Calories: Fats, Carbs, and the Controversial Science of Diet and Health" by Gary Taubes was recommended by my friend Holly. The back of the book claims, "In this groundbreaking book, award-winning science writer Gary Taubes shows us that almost everything we believe about the nature of a healthy diet is wrong." This is not an over-reaching statement. Taubes is not a doctor or a dietician: he's a science writer, and he explores the history of the politics of the science of nutrition with journalistic doggedness. He doesn't seem to set out with a particular hypothesis to prove or disprove. In fact, he says he never expected to find what he found. In that way, it reminds me a bit of "The Omnivore's Dilemma": just a thorough exploration of food without pushing a particular agenda. And this book IS thorough: a good 450 page tome, full of science and history. Sound like a page turner? I admit, it did occasionally get tedious, but generally I found it so compelling that I couldn't put it down.

Basically what he discovers is that the last century of science doesn't actually support what we've been taught about diet: that the way to lose weight is to cut calories and exercise more, that the way to cut cholesterol is to cut your fat intake. It's actually carbohydrates that do the damage. Usually when people go on low fat diets, they compensate by adding carbs, actually doing more harm than good. I can't explain the science very well, but basically, carbs initiate an insulin response, and lots of carbs lead to hyperinsulinemia which leads to metabolic disorder which leads to cardiac problems, diabetes, obesity and maybe even cancer and Alzheimers. The whole theory that fat raises cholesterol which in turn increases risk for cardiac disease is not backed up by good science. The science says carbs, not fat, contribute to heart disease.

What's even more fascinating than the science of nutrition is why and how it's been kept from the public. The history of the politics around all this is bizarre and revealing. And the mis-information is perpetuated by doctors, dietitians and the government. It's become conventional wisdom. It's everywhere.

When I went on the low carb diet in 2008 my doctor warned against it, sincerely worried it would create other health problems. When my cholesterol was inching up a couple years later (a year or so after I'd stopped eating low carb), she sent me to a nutrition class that instructed me to eat a low fat diet. I like my doctor, but her recommendations are not supported by the science. Our whole mentality about diet and health is based on ideas that are not supported by science. Science says bacon and eggs for breakfast is as healthy as you can get. That chili and cheese egg souffle that is all egg and cheese and sour cream is GOOD for you. That bran muffin: not so much. That Jamba Juice protein smoothie: not so much. Big fat steak and a glass of red wine: help yourself! Sounds crazy, huh?

I know you don't believe me. You have to read the book. There is no way you won't be convinced if you do.
Now that I am paying attention to this, it's turning up all over the place: carbs make you produce insulin. Insulin's job is to store fat. In short, grain is bad for you. Sad, isn't it? Have you heard all the studies of the indigenous cultures that had little or no incidence of obesity, cancer or diabetes or other "diseases of civilization" until a Western diet was introduced? Then it all went to hell. What exactly was introduced with that Western diet that compromised health so dramatically? Carbohydrates.

Taubes isn't the only one who has come to this conclusion. The next book I read was "Life Without Bread: How a Low-Carbohydrate Diet Can Save Your Life" by Christian B. Allan, PhD, and Wolfgang Lutz, MD. The back of this book says, "Based on more than forty years of clinical research conducted on over 10,000 patients, this illuminating book unravels the mysteries of nutrition and shows how a low-carbohydrate diet high in healthy fats can reverse--and possibly cure--diabetes, heart disease, gastrointestinal disorders, and obesity, as well as boost strength and endurance." This book covers basically the same information as Taubes' book in half the number of pages. I found it much more tedious to read, however, although that may have been because I had just finished reading 450 pages of basically the same information. Also, these guys did their own research and set out to convey the results, ultimately recommending a 72 carbohydrate a day diet, so their book doesn't have the open minded sense of exhaustive exploration that Taubes presents. Still, it's a much quicker read, so it might be a good choice if you just want to understand how all this works.

Finally, I have to tell you about The Primal Blueprint by Mark Sisson. Don't be put off by the obnoxious cover: Mark and his wife have a Malibu Barbie and Ken look to them that I found off-putting, so I had to throw the cover away and just read the plain, black hardback without it. Because of that, I can't quote the back cover of this one. Both of the first two books I described make reference to our evolutionary history, but Sisson bases his whole approach on it. They all agree that we evolved as hunters and gatherers and have not caught up with the agricultural revolution yet. Our bodies are still meant to eat nuts and berries and fatty meat, not grain and dairy. Sisson has developed a whole "primal" lifestyle to offer his genes the best possible shot at giving him a long and healthy life. It seems to be working well for him so far! This book is a quick and easy read, but serious and well researched. Sisson tries to be cute sometimes, tries to write like he's chatting with a friend. I found it a little annoying, a little gimmicky, but it keeps the book from being dry and tedious. What I like about this book is that he does create a whole primal lifestyle, not just a diet, and he does it in a fun and realistic way. He acknowledges that we have to live in the real world in the 21st century, that we aren't, in fact, still hunters and gatherers. So he adapts his primal ideals to the real world, and he has fun doing it. He makes you WANT to be primal because he makes it look so fun and easy.

He also addresses the issue of exercise, and does so in a refreshing way. He talks about the perils of "chronic cardio" and suggests our bodies are meant to do low level cardio with occasional sprints and heavy lifting. Personally, I have already felt liberated by this model. (Tina B, if you are reading, this is the book for you!)
If you want more information about The Primal Blueprint without reading the book, check out Mark Sisson's website: www.marksdailyapple.com. Also, if you want another take on the same idea, Loren Cordain wrote The Paleo Diet. I haven't read it, but my impression is he has a stricter approach, more restrictive, less fun; plus he says no dairy! That crosses a line.

I have to thank my friend Holly for setting me on this path, and since she's way ahead of me on the journey, I think I'll ask her if she has anything to share on the matter. In the meantime, I find myself in the same place I was exactly three years ago: about to embark on the mission of lowering my carbohydrates. This time, however, it's not a diet for a year to lose 25 lbs. It's a lifelong nutrition choice based on solid research with the goal of living the longest, healthiest life I can. One thing Judith Beck said that stuck with me was something to the effect of, don't start a diet you can't stay on for the rest of your life. I know if I say I can never have a plate of pasta--or even a SANDWICH for goodness' sake--for the rest of my life, this will never work. So it's not all-or-nothing. It's a day-to-day, meal-to-meal choice about life and health. It's kind of exciting! I'll let you know how it goes!