• Henry

Thoughts on the Paleo Diet

*Update: 9/2/15

This article, written by AAron Thier, gives us some more info about what are paleolithic ancestors ate. Here's a revised list of what is "paleo" and what is not:

"WHAT YOU CANNOT EAT:

  1. Flowering plants, or any food derived from or produced by a flowering plant, including:

  • — Leafy greens like lettuce, kale, chard, and spinach

  • — Root vegetables (excluding cycad roots) like potatoes, sweet potatoes, onions, beets, and radishes

  • — Fruits like mangoes, apples, watermelons, raspberries, and coconuts

  • — Nuts (excluding pine nuts), like walnuts, pecans, and hazelnuts

  • — Legumes like lentils, chickpeas, peanuts, and black beans

  • — Cereals like wheat and oats

  • — Pseudo-cereals like quinoa, amaranth, and buckwheat

  • — Cane sugar, maple syrup, and honey

  • — Cooking oils like palm oil, corn oil, and olive oil

  1. Birds, bird eggs, and bird nests

  2. Mammals and mammal-derived products, including: beef, pork, mutton, rabbit, lard, milk, cheese, yogurt, kefir

  3. Lobsters, crabs, and shrimp (excluding mantis shrimp)

  4. Beer, wine, and liquor, except as noted below"

"WHAT YOU CAN EAT:

  1. Algae like nori, spirulina, Irish moss, and sargasso weed

  2. Fiddlehead ferns

  3. Reindeer lichen (Hint: dry and soak, then serve with fish eggs)

  4. Meadow horsetail (Hint: use it like asparagus)

  5. Mushrooms

  6. Conifer products like pine nuts, pine pith, spruce and cedar needles, juniper berries, and fermented drinks made from any of these ingredients (For example: stone pine liqueur. You will need to take care that your stone pine liqueur is made from pine nuts alone and not, like some commercial varieties, from pine nuts in an eau-de-vie base).

  7. Cycad roots like coontie

  8. Gingko nuts

  9. Most invertebrates, including:

  • — Jellyfish

  • — Echinoderms and echinoderm products like sea cucumbers, sea urchins, and urchin roe

  • — Mollusks like nautilus, oysters, and snails

  • — Most insects and arachnids, including: beetles, cockroaches, dragonflies, and scorpions

  • — Mantis shrimp

  1. Amphibians and amphibian eggs

  2. Reptiles and reptile eggs

  3. Fish and fish eggs"

*Update: 8/16/15

This article, published in the Quarterly Review of Biology, examines a new hypothesis on how we evolved from the Paleolithic era. Salivary amylase, which is an enzyme we secrete in our saliva which starts digesting carbohydrates in our mouth, started to be seen in humans in the Paleolithic era. The gene, AMY1, may have developed around the time that humans began to make fire. It is possible that the ability to cook led to humans consuming more starchy carbohydrates which would not be palatable raw. This would mean that our ancestors were more dependent on starchy carbohydrates than previously believed. If this is true, a Paleolithic diet should include plenty of starchy carbohydrates.

Loren Cordain, PhD. claims to be the world's leading expert on the paleo diet. Taken from his site, thepaleodiet.com, these are the basic tenets of the paleo diet:

  • Higher protein intake

  • Lower carbohydrate intake and lower glycemic index

  • Higher fiber intake

  • Moderate to higher fat intake dominated by monounsaturated and polyunsaturated fats with balanced Omega-3 and Omega-6 fats

  • Higher potassium and lower sodium intake

  • Net dietary alkaline load that balances dietary acid

  • Higher intake of, vitamins, minerals, antioxidants, and plant phytochemicals

Seems pretty good to me! Let’s quickly take a look at these:

  1. Higher protein intake

I totally agree! Cordain cites that the average American gets about 15% of their energy intake from protein. For those who exercise and lift weights this is most likely too little, depending on how many calories you are consuming in a day. Setting protein intake as a percentage of calories eaten for the day is not very efficient because energy intake can vary so much. It is better to give a recommendation based off of grams of protein per lb or kg of bodyweight so that protein intake stays more consistent. However, more protein would certainly be a good thing for the average person. So far, I’m on board.

  1. Lower carbohydrate intake and lower glycemic index

Humans were designed to eat carbohydrates and the glycemic index may have at best a slight influence on health and is generally taken out of context. OK Dr. Cordain, you’re starting to lose me here. I’m no longer sure if this diet is for me.

  1. Higher fiber intake

OK you got me, I’m back on board. High fiber intake can lower cholesterol and increase HDL cholesterol and is essential for healthy gut function.

  1. Moderate to higher fat intake dominated by monounsaturated and polyunsaturated fats with balanced Omega-3 and Omega-6 fats

Fat is pretty important to have in your diet. You really don’t need that much to be healthy but I would say a moderate fat intake is perfectly fine. Having a higher intake of omega-3 fats is a great way to reduce inflammation and facilitate healthy brain function. Monounsaturated and polyunsaturated fats are possibly healthier than saturated fats so it’s probably a good idea to have more of these than any other type of fat.

  1. Higher potassium and lower sodium intake

Most people consume too much sodium and too little potassium so this is a reasonable recommendation. It is also theorized that increasing potassium and lowering sodium can reduce blood pressure by restoring a fluid balance.

  1. Net dietary alkaline load that balances dietary acid

An alkaline diet does not have an effect on bone mass, while supplementing with sodium bicarbonate (helps buffer acid and normalize blood pH levels) may increase growth hormone levels and preserve muscle mass. That does not correlate to an “alkaline diet.” Schwalfenberg notes that “certain aspects [of the alkaline diet] have doubtful benefits.” He concludes that the diet itself, which promotes fruit and vegetable intake as well as higher magnesium intake, may be beneficial for health for those reasons.

  1. Higher intake of vitamins, minerals, antioxidants, and plant phytochemicals

This is an excellent recommendation. The average American is lacking in most of these categories of micronutrients. Excellent!

Overall I would say that this diet is going to be pretty beneficial. It has a great foundation (eat more protein, more fiber, and get more micronutrients). It actually reminds me of the Mediterranean diet that possibly has some health benefit. So this is the paleo diet that everyone is going crazy for? What’s the big deal? And what makes it Paleolithic? Well, there’s more to it.

Now Dr. Cordain gives us a list of random foods that for some reason we can’t eat on the diet:

  • Cereal grains

  • Legumes (including peanuts)

  • Dairy

  • Refined sugar

  • Potatoes

  • Processed foods

  • Salt

  • Refined vegetable oils

Wait, no more Cheerios? I thought they were healthy! Oh well…

This is where the Paleo diet starts to lose some credibility. I outlined the premise of the paleo diet above. Is there something that I missed? It doesn’t say anything about completely restricting certain foods. It certainly doesn’t say anything about potatoes, dairy, peanuts, and breakfast cereal. He recommends eating fruits and vegetables but some fruits have a higher glycemic index than some cereals. So why can’t I eat breakfast cereal? Or potatoes?

The hidden reason:

Cordain advocates a hunter-gatherer style diet from the Paleolithic era. This chunk of human history starts 2.6 million years ago when humans invented tools and ends around 10,000 BC which is when the last glacial period ended. Certainly this is a long time period for humans to develop. During the Paleolithic era humans were running around in small groups with stone tools hunting and eating things like vegetables and berries. It is hypothesized that the modern day human brain was only able to develop when humans started to eat animals because there is so much energy in animal meat. In order to hunt animals we had to be able to make tools. This is why modern day homo sapiens evolved from the Paleolithic era.

Does it make sense?

There is also evidence that our paleo ancestors ate legumes and even developed their own version of breakfast cereals. Can I eat those things now, Dr. Cordain? Even better, out of a collection of 97 statues of females from the Paleolithic era, 51 were overweight or obese. From this we can conclude that obesity still existed in hunter-gatherer tribes.

Humans also started to branch out in to different parts of the globe during this era which means that their diets were extremely varied. Some humans would have had access to lakes and oceans and could have eaten a fish-based diet. Others may have subsisted mostly off of fruit and some scavenged meat. Some may have been great hunters and eaten mostly meat. Human beings are incredibly adaptable and able to survive off of many different types of diets. Even today some people mostly eat meat while some choose to only eat vegan foods.

It’s hard to tell whether or not the paleo diet prevented things like type 2 diabetes and heart disease in Paleolithic humans because they simply didn’t live long enough to develop these problems. Gurven et al report that the average lifespan of a Paleolithic human was 15-20 years. They add that average lifespan of humans increases to about 25 when the paleo era ends and humans begin farming. There are other papers that report a sharp increase in mortality around age 40. The average lifespan would be low because there would be much more deaths in infancy than there are today. There really aren’t enough homo sapien skeletons from the Paleolithic era to determine average lifespan for all humans.

Around 10,000 BC humans began planting crops and domesticating animals. At this time there is a sharp increase in population, lifespan, and health problems (i.e. cancer). Humans began to live in urban environments and had more food available than ever. They also didn’t have to spend all day hunting and gathering, thereby reducing their activity level. It’s likely the increase in lifespan as well as the increase in calories and decrease in activity level led to the increase of disease. If anything, our Paleolithic ancestors show us how incredibly adaptable the human body is to different food sources, and how important exercise is to overall health.

Let’s look at some real paleo diet data now.

Jönssen et al determined that the paleo diet is more satiating than the Mediterranean diet. They suspect that this may be due to the higher protein content of the paleo diet, or the fact that that source of carbohydrates is more filling (fruit and veggies as opposed to grains). This may make it easier to lose weight on the paleo diet, since increased satiety means you may eat less.

Jönssen et al in a different study compared the paleo diet to a diabetes diet in subjects with type 2 diabetes. The paleo diet was once again considered more satiating, however it also had a higher glycemic load, which may be harmful to a type 2 diabetic. The researchers note that the paleo diet group experienced more weight loss but the participants also found the diet difficult to adhere to. This implies that they probably lost weight due to a lack of calorie intake and that the diet is unrealistic as a long-term solution to obesity and other health problems.

Punder et al studied the effects of wheat products in gluten-sensitive individuals and concluded that wheat products may increase inflammation due to a stimulated immune response in these individuals. This implies that the paleo diet may be beneficial to gluten intolerant individuals which is only a small percentage of the population.

Boers et al conducted a pilot study on the paleo diet. For two weeks they had a group of middle aged men adhere to either the paleo diet or a diet from the Dutch Health Council. The paleo diet group had lower LDL cholesterol, systolic and diastolic blood pressure, and triglycerides. It is important to note that the paleo group was not able to maintain their bodyweight and that these improvements in markers of health may be due to the fact that they lost weight.

Burgess-Champoux performed a review of studies on the paleo diet. She found that two studies resulted in lowered blood pressure, four studies resulted in reduced energy intake, and two resulted in increased insulin sensitivity. These benefits can all be explained by increased satiety of the paleo diet and any health benefits can be attributed simply to decreased calorie intake.

What you can take away from this:

Whether or not the paleo diet works for health is part of a larger debate that really has nothing to do with the paleo diet itself. Literature shows that decreased carbohydrate intake may lower cholesterol, triglyceride levels, and improve insulin sensitivity within a 6 month period. After this initial 6 month period a low carbohydrate diet doesn’t consistently show a benefit. These health benefits are all seen with an increase in physical activity. If we look at our Paleolithic ancestors we can assume that they were active for most of the day. As human societies get more advanced we have less and less need for physical activity. It has recently been shown that physical activity and muscle mass are both correlated to longevity. If your goal is health start with physical activity and see what happens. If you take anything from the paleo diet it should be: increased protein intake, eating more fruits and vegetables, and consuming more omega-3 fatty acid.

If you are looking to get more muscular or lean out, the paleo diet is absolutely not for you. In order to perform well in the gym and gain muscle you need to increase calories and carbohydrates. The paleo diet makes it hard to eat enough food because it is so satiating. It also emphasizes a low carbohydrate intake. The paleo diet is not conducive to performance.

A word of caution:

Any diet that emphasizes restricting certain types of food is dangerous and ineffective. Restrictive diets can lead to eating disorders and depression. They are also difficult to adhere to and will likely lead to a negative relationship with food. You need to make your diet work for you. If you happen to love eating meat, fruit, vegetables, and nothing else then go ahead. If you like dairy and various carbohydrate sources then eat those foods. It is very important that you do not completely restrict certain foods.