Thursday, January 31, 2013

The Next Fad Diet?

This post was not originally on my list of potential upcoming topics but was spurred in part by two different questions I was asked.  The first was at a recent public event I participated in.  A question asked to the cardiologist on the panel and later passed on to me was in regard to the healthiness s of low carbohydrate/high protein diets.  The cardiologist provided a brief and sound although slightly incorrect answer.  I continued his own response by explaining the differences between “dieting” and “lifestyle change” (which I will come back to later) as well as a short break down of several of the more popular diets in question.  The next day I received an email from my sister in-law asking me about “The Paleo Diet”.  This was an important email for two completely different reasons.
  1. While I was familiar with the paleo diet, my familiarity was only based on what little I had read from a magazine article and seen summarized on the  The email provided a spark which has led to a great deal of further reading
  2. This was to my knowledge, the first time my sister-in-law had ever asked my medical opinion of something.   Ah…warm fuzzy feeling.

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The Paleolithic Diet (or hunter-gather diet) is comprised of high quantities of lean meats, fruits, and vegetables with minimal to no processed carbohydrates, dairy, potatoes or legumes. 
The exact definition per is:

The Paleo Diet is based upon eating wholesome, contemporary foods from the food groups our hunter-gatherer ancestors would have thrived on during the Paleolithic era, the time period from about 2.6 million years ago to the beginning of the agricultural revolution, about 10,000 years ago. These foods include fresh meats, fish, seafood, fresh fruits, vegetables, seeds, nuts, and healthful oils. Dairy products, cereal grains, legumes, refined sugars and processed foods were not part of our ancestral menu.

It all sounds well and good but is it?  Read on while I blow some serious holes in this dietary theory while pointing out its strong points as well.  My synopsis is included at the end and may surprise you.  It is also important to realize that the paleolithic diet principles are based mostly on evolutionary concepts than actual nutrient fullfillment.

THE CLAIMS (and rebuttal):

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Genetic Adaptation – The general principle of the paleo diet is that humans are genetically adapted to the diet of our ancestors who were for the most part hunter-gathers until the advent of agriculture and animal husbandry around 12,000 years ago.  After all, those that couldn't  adapt to the food sources available were not destined to carry on.  The paleo diet seems to ignore the fact that we did not stop evolving 12,000 years ago.  In fact DNA evidence from early genetic ancestors reveals that many had poor ability to process dairy, starch, and gluten.  However today, a vast majority of European and African descendants can fully process dairy without difficulty due to gene adaptation.  Further, gluten intolerance, while all the rage on the bookshelf, is actually only found in about 1 out of every 300 Caucasians and is even less common in other races.  

Diseases of civilization – Paleo enthusiasts claim that the “western diet” has lead to “diseases of civilization” including cancers, heart disease, hypertension, and obesity.  They claim these did not exist prior to the advent of the western diet.  There a few problems with this line of reasoning.
  1. No evidence – We have no idea if those in the Paleolithic or early human era suffered these diseases.  No records exist and there is very little physical remains left to make such an assumption.  Rather this concept is based on observational studies of a few small hunter-gather tribes that still exist today.  These tribes have very limited genetic variation and numerous other factors that likely contribute to their lack of “diseases of civilization”.  It’s correlation without causation.
  2. Life Span – Almost all diseases of civilization occur much later in life except perhaps obesity which has more to do with reduced activity (sedentary) than it does with the actual diet.  You can eat at McDonalds every day and run 20 miles and not gain weight.   Our ancestor’s possible lack of these diseases was due to their 30 year life span, not their diet.  They didn't have time to develop these diseases.  And why was the life span so short?  Mostly due to acquired disease (germs) and malnutrition!

Meat Eaters – Like many newer diets this one advocates for large amounts of lean protein.  The goal is get 55-60% of your energy from animal sources per the website.  That isn't such a bad goal but what most people equate that to is 55% of their plate.  In general protein is much more calorie dense and it likely would take only 10-20% of your intake in volume to equal 55% of your energy need.   Thus many people on the paleo diet are actually consuming much more protein than the diet actually advocates for.  This is not a fault of the paleo diet but rather that of many of the participants.

Yeah Veggies & Fruits - The paleo diet is much less restrictive than Atkins and even South Beach in regards to vegetable and fruit consumption.  It emphasizes both soluble and non-soluble fiber intake.  This is one of the ideal aspects of going paleo.

Grains, legumes and potatoes are bad – While I am not a huge supporter of processed foods or baked goods, whole grains are for the most part not a bad part of a healthy diet.  The problem usually comes from the ease in which one can overindulge in carbohydrate dense products.  Contrary to paleo supporter’s statements, most people can fully process and utilize whole grain foods which have good fiber content as well.  Food anthropologists state that grains, root vegetables, potatoes, and legumes began being domesticated about 10-11,000 years ago but were likely “gathered” by earlier humans for many years before we developed for agriculture.  These earlier humans wouldn't have taken the time and effort to domesticate food sources that they were unable to tolerate/process.  

No Dairy – Dairy is generally avoided in the paleo diet based more on principles of Paleolithic availability rather than actual dietary guidance.   Dairy based products would not have been available until the advent of animal husbandry 10,000 or so years ago.  Most humans, especially Europeans now carry the genes needed to process dairy and there is evidence of cheese production going back as far as 7-8000 years ago!  The paleo diet in its pure forms appears to be significantly lacking in calcium.  Its an odd restriction to me.  If you were a classic car guy would you not use seat belts because they didn't use to have them?

Malnutrition – Our ancestors likely needed a massively larger quantity of calories to fuel their hunter-gatherer life style thus necessitating the large amount of animal sources for food.  (Unfortunately it does not take a whole lot of energy to hunt for the stapler and gather papers in the office).  Some estimate that early humans required as much as 4000 calories a day.   Gathering 4000 calories worth of vegetable matter a day would be very difficult in many areas of the paleolithic world (however I can do it in my pantry while staying on one shelf).  Further, most areas of the world have a fairly limited variety of naturally occurring food plants.  Thus most hunter-gathers would have had a restrictive diet leading to significant deficiencies in certain vitamins and minerals especially calcium.   Those in colder environments likely lived off of purely animal sources for months at a time.  

The Acid-Base Balance – I have decided to not spend a great deal of time on this aspect however from what I have read the evidence behind this principle is good in theory however I have doubts as to how much diet actually plays a role.

Salt, Sugar, and Alcohol (aka “the good stuff”) – I don’t like diets that eliminate these purely on principle.  People tend to crave these items when they are missing from a balanced diet and cravings often lead to failure of the diet.  This is likely why many nutritionists feel the paleo diet is very hard to stick with.
  1. Added sugar is generally regarded as a poor dietary principle.  A little is okay once in a while but no one thinks it’s good for you in abundance.  
  2. Alcohol on the other hand has minimal nutrient value but does have several other healthy qualities in limited quantity.  Our Paleolithic ancestors likely didn’t consume but they surely would have had they known how to make it.  
  3. Salt is perhaps the most obvious and yet controversial restriction of this diet.   A diet without added salt tends to be a diet without much flavor.  The evidence against salt is actually very poor.  While Americans consume more salt than recommended on a whole only a small percentage of people actually have negative consequences of this.  Salt restriction while a staple of hypertension treatment has actually only been shown to improve blood pressure in a small percentage of patients.  If you haven’t read the book, Salt: A World History, I highly suggest it.  You can get it here:  SALT


A 2011 ranking by U.S. News & World Report, involving a panel of 22 experts, ranked the Paleo diet lowest of the 20 diets evaluated based on factors including health, weight-loss and ease of following.  I personally think that is odd as the paleo diet is easier to follow than several other fad diets.  I do though suspect that it is likely not a great weight loss diet unless it is a drastic change from your current diet.

The largest proponent of the paleo diet is nutritionist Dr. Loren Cordain.  Dr. Cordain has published numerous articles about the paleo diet approach and is very well educated in the field.  Unfortunately most of his publications are either observational studies or of very limited sample size and length.  Dr. Cordain has written numerous books on the subject and makes his living through sales of paleo diet related literature. 


The Paleolithic diet is definitely not my favorite diet.  But overall it’s not a horrible diet.  In fact I think it has many sound principles.  I love the focus on vegetables and lean meats however I think some of its restrictions are based on poor science at best.   I do think the paleo diet would be a difficult lifestyle to stick to. 

I advocate for my patients to keep their diet focused on large amounts of both fresh and cooked vegetables, fresh fruits, leans meats, and healthy fats much like the paleo diet.  However I encourage the use of lean dairy and limited whole grains and legumes.   

The most important factor when deciding on a diet is not necessarily the principles, but the ability to follow through with it long term.  When I talk to patients about their weight and diet I try to get them to focus on a LIFESTYLE CHANGE.  Any “fad diet” can get you to drop a few pounds quickly but in the end almost everyone puts that weight  back on when they stop “dieting”.  It’s not about dieting it’s about changing your nutritional life style.

Lean meats & eggs
Fresh & cooked vegetables (including legumes)
Fresh & frozen fruits
Potatoes – limit 1-2 times weekly
Pasta or rice – limit 1-2 times weekly
Olive, canola, or grape seed oil
Butter (limited)
Low fat milk and yogurt
Cheese (limited)
Nuts and seeds

Extra bread with meals
Processed baked goods
Non-whole grains
High fructose corn syrup
Added sugar & sweet beverages
Fried foods

Breakfast – Greek yogurt and fresh fruit or cooked egg on slice of bread
Lunch – Mixed greens with fresh vegetables and 3oz of lean protein or cheese
Snack – Cottage cheese, piece of fruit, or handful of nuts
Dinner – 2 servings of sautéed vegetables, 5-6oz of lean protein, and 1 serving of carbohydrate
Dessert – Fruit, bite of chocolate, or glass of wine


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