Matt Metzgar

Case In Point

Following up on my last post, take a look at this study that compared a low-carb, low-fat, and a Mediterranean diet for weight loss after two years.  The result for low-carb?  A whopping 10 pounds of weight loss.  And this was for subjects who started out as "moderately obese".

Also of interest is how the Atkins foundation responded: "It is a vindication," said Abby Bloch of the Dr. Robert C. and Veronica Atkins Foundation.  Why is a 10 pound weight loss over two years a vindication (or a victory)?  

You have to love spin...

Where Are The Low-Carb Studies?

Looking at the research, you can see a surge of low-carb studies that have been done over the past few years.  Still, I am wondering: where are the long-term studies that show low-carb is effective for weight loss?  Most of the studies I read show outcomes after 6 or 12 weeks.  Almost any diet can show weight loss in this short time span, before the rebound effect usually begins.

As far as I know, there are only two long-term low-carb weight loss studies (I'm defining long-term as 18 months or more).  Both show minimal weight loss for Atkins/low-carb.  You would think that since Atkins' diet book was originally published in the early 70s, thirty years would be enough time to produce some legitimate long-term studies.

All this isn't to say low-carb does or doesn't work for long-term weight loss.  Instead I'm just asking, where is the proof (beyond personal stories)?  People jumped on the low-fat bandwagon in the 80s because of short-term studies.  If low-carb is going to be more than this decade's bandwagon, there needs to be better studies done.

Diabetes and Diet

I have been looking at this study on diabetes that was published last year.  The study compared a ketogenic low-carbohydrate diet versus a low-glycemic diet in the treatment of type 2 diabetes.  The low-carbohydrate diet was found to more effective.  In fact, 95% of subjects on the low-carb diet were able to reduce or eliminate their medications.

95% - that seems like a lot to me!  Actually, only 50% of the low-carb subjects actually completed the study, so it's 95% of those who were willing and able to eat in this way.  Still, you would think that such results would trumpeted on the news.  Instead, I've never heard about the study.

Some of the research on diabetes is so frustrating.  I see researchers trying to make all kinds of complex connections.  Why don't they start with a simple premise, like: since carbohydrates are the biggest determinant of blood sugar levels, then let's focus on modifying or restricting carbohydrate consumption.

Even partial carbohydrate restriction works.  This study of diabetic patients found that just eating a diet of 45% carbs instead of the typical 57% lead to improvements over a two-year period.  It's time to put this information to use.  It doesn't take a genius to figure out that carbohydrates are at the root of type 2 diabetes.

Some Thoughts About Carbohydrates

Carbohydrates can be a tricky nutrient to analyze.  Part of the problem is that there are different effects over different time periods.  For example, I wrote earlier about how people in the US consumed an average of 500 grams of carbohydrates per day in 1909.  So why was obesity and diabetes rare back then?  I think there are a few reasons:

• First, people were more physically active and therefore they could burn off the glucose consumed (for example, manual labor jobs)
• Second, the carbohydrates were generally not refined
• Third, people were born from healthier mothers, and began life with normal insulin levels

This third point has becoming increasingly important in recent years.  The Paleo Diet newsletter pointed out a new paper that shows how insulin resistance can start in the womb, and then greatly increase the odds of the child being insulin resistant throughout his or her life.

What's happening now, I think, is that there is a whole constellation of factors that are making people less tolerant of carbohydrates.  Activity is down.  Carbohydrates are refined.  And the insulin resistance of one generation is being passed to the next, with each round making the problem worse.

That's why you can look at a population like the Kitavans, and see no problems from a high-carbohydrate diet.  They have historically eaten unrefined carbs, and therefore they never developed any insulin resistance to pass down to the next generation.  If you feed this high-carb diet (even if it's unrefined) to a modern insulin resistant child or adult, it may end up making things worse.

Hair As A Health Indicator

One thing I've become aware of is how hair can serve as a health indicator.  I've noticed that if I increase the fat content in my diet, my hair feels healthier.  I think hair is a health indicator that is underused by the medical profession.  Couldn't a hair analysis be a part of a health checkup?  I bet it would provide some very valuable health information.

I read somewhere that there is an evolutionary reason for women to have long hair.  The idea was that long hair provides a "track record" of a person's health over the last couple years.  If a young woman has nice long hair, it is a clue that she has good resistance to infection/disease, and therefore would make a good mate.  You also often see an age difference in hair length with young women favoring longer hair, and older women having short hair.

You can also look at the hair product industry and see how much people are willing to spend for good hair.  Especially for women's hair care products, I would guess the annual sales are in billions.  Certainly, hair is more than just a covering for the top of the head.  In Paleolithic times, hair was probably a key indicator of access to quality food and resistance to disease.

Why Don't Gymnasts Wear Shoes?

It's funny how tradition dominates the use of footwear in sports.  Most people would think it is normal to see a gymnast perform barefoot, but not a baseball player.  This brings up a good question: if shoes are so important for improving athletic performance, then why don't gymnasts wear shoes?  Certainly, gymnastics is one of the most athletic sports, with high-impact landings on the feet.  Yet I've never seen a gymnast performing in shoes, or even practicing in them. 

Related to this, here is a study(pdf) that looks at the plantar sensitivity of gymnasts and volleyball players.  The researchers wanted to test athletes who either regularly participated in a barefoot sport (gymnastics) or a sport that uses shoes (volleyball).  The study found that gymnasts had better sensitivity in their feet.  Better sensitivity in the feet also correlates with better posture, as I written about recently.  Therefore, I would also expect the gymnasts to have better posture than the volleyball players, even though this wasn't part of the study.

Just as you now see top runners doing some barefoot training, I think other top athletes may eventually use some barefoot training for their particular sports.

Correct Toes

I came across this interesting product called, "Correct Toes".  The idea is that in traditional cultures, people have naturally spaced out toes due to less constrictive footwear.  In the modern world, many people have their toes compressed together due to the narrow toe boxes in most shoes. I know my feet look like those on the right in the photo below:

I have no idea if this product actually works.  Here is one review of it.  A clinical study is supposedly under way.  It does look like these would fit nicely within the wide toe box of Vivo Barefoot shoes.

Toes and Posture

Here's a study(pdf) that looks at toe grasp training in the elderly.  The study mentions that the elderly tend to rely more on sight rather than feedback from the feet in maintaining balance.  Subjects performed simple toe grasp training for 8 weeks.  This consisted of exercises like gathering a towel with the toes and picking up objects with the toes.

The study found that toe grasp training was effective in reducing postural sway, and could be used to prevent falls in the elderly.

Foot Sensitivity and Locomotion

This is an interesting study that looks at plantar sensitivity and gait.  Subjects had their gait measured in barefoot conditions.  Then an anesthetic was used to numb the nerves in the bottom of the foot.  Some interesting things then happened: leg stiffness decreased (which is not a good thing in running).  Ground time increased (and flight time decreased).  Peak force was also lower.

The article has some interesting quotes: "The plantar surface of the foot is the only part of the body to encounter the ground during bipedal locomotion. It would seem logical that some aspect of the neurological functioning of the foot is responsible for transmission of information about the surface characteristics to the central nervous system (CNS), resulting in changes in leg stiffness."

"With regard to human locomotion, the ability to alter the stiffness of the leg spring is essential to maintaining an efficient gait. When running or hopping over the ground, the stored energy is constantly stored and returned in the musculoskeletal system."

Shoes decrease the tactile sensitivity of the foot.  Wouldn't it then follow that running in shoes would lead to a less efficient gait?  

It makes sense to me...

Footwear and Aging

I have been reading through this older study on footwear.  The study looked at the awareness of foot position in both the young and old, in barefoot or in shoes.  For the young and old, shoes led to decreased awareness of foot position.  In the young, this was a large difference.  In the old, however, this was only a very small difference.  The authors conclude that: "sensitivity to foot position declines with age, mainly owing to loss of plantar tactile sensitivity. Footwear impairs foot position awareness in both young and old."

I had a few thoughts on this.  In the paper, they talk about how somatosensory ability declines with age, but not evenly across the body.  In the hands, for example, there is only a small loss of abilty.  In the feet, there appears to be a much larger loss.  I think the simplest explanation is that our feet are covered in shoes much of our life, while our hands are not.  I would love to see if foot sensitivity declines in barefoot populations with age.  I would bet not, or perhaps only a small amount.

Therefore, in this study, is the loss of foot sensitivity in the old due to aging, or is it due to a lifetime of wearing shoes?  Enquiring minds want to know.