The Carb Report: Part 3

Part 3 of the Precision Nutrition Low Carb Diet Special Report…

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THE PALEO PROBLEM

LOOKING AT THE PROS AND CONS OF THE PALEO DIET

What is “Paleo”?

The Paleo, or primal, diet is based on the idea that we adapted to eat particular kinds of foods and in order to be as healthy, fit, and strong as possible – and to avoid modern chronic diseases – we should eat like our ancestors did.

A brief history

The earliest primates lived more than 60 million years ago, and like most primates today they ate mostly fruit, leaves, and insects.

About 2.6 million years ago, the Paleolithic era, things changed. Our early human ancestors started using tools and fire and changed their diet. By the time modern humans came along about 50,000 years later, we were eating an omnivorous hunter-gatherer diet.

The basics

The Paleo diet includes:

  • animals – meat, fish, insects, reptiles, etc. – almost all part of the animals including organs
  • animal products – e.g. eggs, honey
  • fruits
  • nuts and seeds (raw)
  • roots/tubers, leaves, flowers, stems – i.e. vegetables

Recently, some Paleo groups have suggested that eaters start with the above mentioned foods and then slowly introduce grass-fed dairy (yogurt and other cultured foods) and small amount of legumes that have been soaked overnight.

 

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Why do we care about hunter-gatherers?

About 10,000 years ago, most of the world have figured out agriculture, thus moving us from the Paleolithic to the Neolithic period. Planting and farming provided us with a consistent and relatively reliable food supply. However, the 10,000 year time from since the Neolithic period began represents such a small part of the time humans have been on the planet.

Many people believe that the change from a hunting and gathering diet (rich in wild fruits and vegetables) to an agricultural diet (rich in cereal grains) gave rise to our modern chronic diseases such as obesity, diabetes, and cardiovascular disease.

This is a major reason why proponents of the Paleo diet say we need to return to the meat- and produce-based diet of our ancestors.

Hunter-Gatherer-Diets

But, wait, didn’t they all die?

While we have skeletal remains, cooking sites, and other types of evidence left behind to give us an idea of what our ancestors were like, we don’t have detailed medical records of how they fared.

But, we do have real, current populations we can study.

A few surviving hunter-gatherer populations still exist and subsist on a wide variety of diets – from the nut-and-seed-based African !Kung, to the root vegetable Kitavans near Papua New Guinea, and the meat and blubber Inuit of the Arctic. Wow! What diverse diets they all have, huh!? This is simply because what our ancestors ate depended on where they lived.

However varied their diets anywhere in the world, most Paleolithic peoples likely ate about three time more produce than the typical American as well as more fiber, protein, omega-3 fatty acids, unsaturated fat, vitamins and minerals, and much less sodium and saturated fat.

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What Paleo Promises

The main idea of a primal diet is that our ancient human genetics don’t match with our current 21st century diet and lifestyle, and our health and well-being is suffering because of it.

The Paleo diet also makes some important assumptions:

  1. Paleolithic hunter-gatherers were healthy and robust – if they hadn’t died young from accidents or infectious diseases they would have lived about as long as we do now
  2. When Paleolithic hunter-gatherers shifted to a Neolithic agriculture they got sicker and shorter
  3. Modern hunter-gatherers are healthy and they health declines when they switch to a modern diet

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Show me the evidence!

Actually, hunter-gatherers were not the models of health that they are sometimes made out to be. They were subject to many infectious diseases and parasites and studies examining mummies show high rates of atherosclerosis (hardening of the arteries).

Diseases of affluence and industrialization

Rates of diseases of affluence (e.g. obesity, diabetes, and cardiovascular diseases) have increased over the past generation in industrialized countries like the United States, especially compared to developing, non-industrialized nations.

Industrialization and technological advances have exploded over the past century, radically impacting the way we live and eat. Today, the average American eats primarily packaged and commercially prepared foods – rich in refined sugars and starches, highly processed fats, and sodium. Delicious, yes, but also designed to encourage overeating.

The top 6 sources of calories in the typical American diet today are:
grain-based desserts (cake, cookies, etc.)
yeast breads
chicken-based dishes
sugar sweetened beverages
alcoholic drinks
pizza

Clearly these were not foods that our ancestors ate, nor are they particularly good for your health.

All Fruit Final

Is the Paleo diet really Paleo?

Recall that there is no single, defined “Paleo” diet as our ancestors ate whatever they had access to in their respective environments.

However, we can be fairly certain that primal diets included more fruits and vegetables than most people are eating today. So, if we want to be healthier, we need to eat a lot of fruits and vegetables… right?

Well… maybe.

Most modern fruits and vegetables are not like the ones our ancestors ate. Over time, we have selectively bred plants with the most preferable traits – the biggest fruits, prettiest colors, sweetest taste, fewest natural toxins, and largest crop yields. We have also diversified and created new cultivars.

Similarly, modern animal foods have changed. Beef (even if grass-fed) is not the same as bison or deer.

This does not mean that modern produce or meat is inherently good or bad, just different. So the argument that we should eat a diet rich in vegetables, fruits, and meats because we evolved to eat these foods is suspect – the ones we eat today are completely different than those that existed in the Paleolithic era.

Grasses and grains

Paleo diets usually exclude grains, legumes, and dairy foods, stating that these were not in our diets before 10,000 years ago and that is not enough time for our species to adapt to these “new” foods.

Unfortunately for them, this contention is flawed:

  • Recent studies show that ancient humans may have begun eating grasses and cereals before the Paleolithic era – up to three or four million years ago
  • More research has shown granules of grains and cereal grasses on stone stools starting at least 105,000 years ago and grain granules on grinding tools from all over the world suggest that Paleolithic humans made a widespread practice of turning grains into flour as far back as 30,000 years ago

“Fact” BUSTED!

Are beans bad?

Legumes (beans, peanuts, peas, lentils) are limited in the Paleo diet for a similar reason as for grains, and the evidence refuting it is the same. A 2009 review revealed that legumes were actually an important part of our Paleolithic ancestors’ diets.

The anti-nutrient argument

Paleo proponents also offer another explanation for their dietary restrictions: the high concentration of anti-nutrients in these foods that reduces their nutritional value.

The problem? They’re wrong.

Research suggests that the health benefits of consuming legumes far outweigh their anti-nutrient content, especially since the process of cooking removes most of their anti-nutrient effects – lectins and protease inhibitors especially. Once cooked, they may actually be good for us. Lectins may reduce tumor growth and protease inhibitors become anti-inflammatory and anti-carcinogenic.

Phytic acid

Grains, nuts, and legumes are rich sources of phytate, an anti-nutrient which can bind to minerals such as zinc and iron thus preventing their absorption. While phytic acid can be toxic if eaten in too great of an amount, in more reasonable amounts it actually is beneficial:

  • antioxidant activity
  • DNA protection
  • prebiotic (food for your gut bacteria)
  • anti-cancer properties
  • reduced bioavailability of heavy metals

Nearly all foods contain anti-nutrients as well as nutrients – plant foods in particular. Like most things, phytic acid, lectins, and other anti-nutrients probably have a “sweet spot” – eating none or a small amount might be inconsequential, eating a moderate amount may be good, and eating too much may hurt you.

Grains and inflammation

Another argument for Paleo is that eating grains leads to inflammation and related health problems.

While this can be true for those with celiac disease and non-celiac gluten sensitivity, most research does not support this argument.

In fact, observational research has suggested that whole grains may decrease inflammation while refined grains may increase inflammation.

It appears that processing may cause problems, not the grains themselves.

Furthermore, controlled trials consistently show that eating grains (refined or otherwise) does not affect inflammation at all. At worst, whole grains appear to be neutral when it comes to inflammation.

A large body of evidence suggests that eating whole grains and legumes improves our health:

  • improved blood lipids
  • better blood sugar control
  • less inflammation
  • lower risk of stroke and coronary heart disease

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A history of the human GI tract

It sometimes argued that, even though the world has changed quite a lot in the past 10,000 years, our genes actually haven’t changed that much, and we can only thrive in a world with similar conditions as those encountered in the Paleolithic era.

This is not how evolution or genetics work.

If humans could only thrive in an environment similar to the one of their ancestors, our species would have died out already.

As a species, many of us have evolved the capacity to consume dairy even as adults. We are evolving a mutation that allows us to continue producing the enzyme lactase which allows the body to break down lactose for much longer in life than our ancestors could. Not everyone can digest dairy well, but more of us can than ever before – and even those who don’t digest lactose well are capable of consuming smaller amounts of dairy with few to no symptoms.

A genetic “blueprint” is not enough on its own – genes can be switched “on” or “off” by a host of physiological and environmental cues.

Our digestive systems have adapted to process a low-energy, nutrient-poor, presumably high-fiber diet. Meanwhile, Western diets are generally high-energy, low-fiber, and high-fat. How is it that we are still able to digest our food, although at time imperfectly?

Enter: the gut microbiome. The bacteria that live in our gut interact with our food by helping us break down tough plant fibers, release phytonutrients and antioxidants that were bound, and assist in assimilation of important compounds.

We don’t have direct evidence of what bacterial species inhabited our ancestors, but we can be sure that they would not match our own today. Bacteria evolve and adapt at a rate much faster than human genes. That’s actually a good thing, for us.

Why? Because even if ancient human diets did not include grains, legumes, or dairy, we might still thrive on such a diet today – with the help of our microbiome.

Magical microbiome

The Human Microbiome Project, along with other research projects around the world, has given us a pretty good picture of the trillions of microorganisms and thousands of different species that inhabit our bodies. Most of the genetic material that you carry around actually doesn’t even belong to you – it belongs to them!

This genetic diversity ensures that our GI tracts can adapt quickly to changes in diet and lifestyle.

A single meal can change the type of bacteria that populate your gut.

Many of us can break down “modern” foods that Paleo advocates say we cannot simply because our intestines contain bacteria that have evolved to do the work.

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Modern Paleo research

So, as you can see, the arguments just don’t hold up.

HOWEVER, this does NOT mean that the diet itself is necessarily bad. Just probably for different reasons than those presented.

Paleo vs. Mediterranean diets

In one clinical trial, diabetic and pre-diabetic volunteers were divided into two diet groups:

  • Paleo diet – lean meat, fish, fruit, vegetables, starchy root vegetables, eggs, nuts
  • Mediterranean diet – whole grains, low-fat dairy, vegetables, fruit, fish, oils, margarine

Both groups, after following one diet or the other for 12 weeks, lost weight and saw an improvement in markers of diabetes. In fact, the Paleo group lost more body fat and showed greater normalization of blood sugar levels.

Other research has found that the Paleo diet is more satiating per calorie than the Mediterranean diet and the Paleo diet improves blood pressure, glucose tolerance, and blood lipids. (However, macronutrient ratios – like protein – were not matched – with the Paleo group eating more protein.)

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What does this mean for you?

In the end, the Paleo diet gets more right than it gets wrong:

  • Paleo-style eating emphasizes whole foods, lean proteins, vegetables, fruits, nuts, seeds, and other healthy fats, which is a massive improvement over the average Western diet
  • Paleo-style eating has been effecting for improving several chronic diseases
  • Paleo-style eating has made us more aware of how processed and crappy a lot of our modern food is

However, we need more rigorous scientific trials before we can reach any definitive conclusions.

Despite the benefits, the Paleo diet does have flaws:

  • the evidence for excluding dairy, legumes, and grains isn’t strong – at least not on a non-individualized level
  • the evolutionary arguments don’t hold up – we are an ever-evolving accumulation of inherited characteristics (and our microorganisms)
  • strictly following a list of “allowed” and “good” or “not allowed” and “bad” foods does not work for most people – this all-or-nothing thinking is not effective over the long-term because it ultimately leads to decreased consistency

Some Paleo advocates have more recently liberalized the diet to include moderate amounts of starch (such as in sweet potatoes – still limited variety), dark chocolate, red wine, tequila, and grass-fed dairy. These additions may make like more enjoyable and make a healthy eating pattern more achievable.

In the end, moderation, sustainability, and personal preference are what matters most. Interested in following a Paleo diet? Work with a dietitian to ensure you are fueling and nourishing your body right.

SOURCE
PrecisionNutrition.com Low Carb Diet Special Report by Brian St. Pierre MS RD.
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