The first part of the “Understanding the Paleo Diet” series provides a basic understanding of what the diet is about. How to follow the Paleo Diet is one thing … understanding how the Paleo Diet works is another topic worth exploring.
The Science Behind the Paleo Diet
A diet rich in fruits, vegetables, lean protein, and omega 3 fatty acids improve our body’s ability to make use of food rather than storing it as fat or having it remain in the bloodstream as excess sugar. The rationale behind eliminating grains and starchy carbs is supported by studies that show they significantly raise blood sugar more than fructose, the sugar molecule found in fruits and veggies. In addition, the low carb profile of the Paleo Diet has been shown to lower systemic inflammation in tissues, which in turn aids in the prevention of chronic degenerative disease. There are also numerous studies that show one can reduce abdominal fat, decrease blood pressure, and lower bad cholesterol levels by minimizing grains, dairy, legumes and refined sugars.
Despite this evidence, the Paleo Diet remains controversial. In its 2013 evaluation of the “Best Diets for Healthy Eating,” U.S. News and World Report gave the Paleo Diet a rating of two out of five stars, placing it next to last out of 29 diets under review. Experts have shown concern about dieters failing to get key nutrients while on the Paleo Diet (because it eliminates entire food groups). As a result, it scored poorly under the categories of weight loss, ease and convenience, nutrition, safety, diabetes and heart health. Some who dispute the merits of eliminating whole food groups while on the Paleo Diet point to evidence that legumes and whole grains have been shown to reduce the risk of disease, improve insulin sensitivity and blood sugar levels, and decrease BMI.
Paleo Diet advocates, on the other hand, argue that legumes, grains and potatoes contain high levels of anti-nutrients (i.e. lectin, phytate and saponin). These compounds, according to the Paleo philosophy, block digestive enzymes, promote inflammation, and contribute to the onset of autoimmune diseases and cancer.
Others express concern that the Paleo Diet doesn’t provide enough calcium. The good news here, however, is that dairy (which is not included in the Paleo Diet) is not the only concentrated source of calcium in the human diet. Leafy greens (like spinach, kale, swiss chard, rhubarb and broccoli) may be an even better source when it comes to absorption of this important nutrient. Plant-based sources of calcium are generally more absorbable than animal sources because they can be digested easier and are broken down and utilized more effectively.
One of the strongest critiques of the Paleo Diet comes from Karl Fenst, a bioarchaeologist. In his 2012 keynote address, “Papayas Ain’t Paleo, and Neither Are You”, at an international conference of anthropologists, archaeologists, and molecular biologists, Dr. Fenst attacked the idea that agricultural products are somehow “unnatural,” with wheat being specifically singled out. “Nearly every food item you currently eat has been modified from its ancestral form, typically in a drastic way,” he began. “The notion that we have not yet adapted to eat wheat, yet we have had sufficient time to adapt to kale is ridiculous. In fact, for most practitioners of the Paleo Diet, who are typically westerners, the majority of the food they consume has been available to their gene pool for less than five centuries. Tomatoes, peppers, squash, potatoes, avocados, pecans, cashews, and blueberries are all New World crops, and have only been on the dinner table of African and Eurasian populations for probably 10 generations of their evolutionary history. Europeans have been eating grain for the last 10,000 years; we’ve been eating sweet potatoes for less than 500. Yet the human body has seemingly adapted perfectly well to yams, let alone pineapple and sunflower seeds.”
In a Q & A session afterwards, Dr. Fenst provided some clarification into what he felt was at the heart of the issue: “The real problem is that people are cherry-picking data to sell this diet, and that it seriously misrepresents the historical and evolutionary development of our species.
Dr. David Katz, Founding Director of Yale University’s Prevention Research Center, puts his critique another way: “Fundamentally, I am a proponent of the Paleolithic Diet. In reality, virtually no one today practices anything close to a true Stone Age diet. When was the last time you saw a mammoth? When the Paleo Diet label is used to justify a diet of sausages and bacon cheeseburgers, the concept has wandered well off the reservation. When used as guidance away from processed foods and toward a diet based on a variety of plants, nuts, seeds, eggs, fish and lean meats, it is eminently reasonable, and no doubt a vast improvement over the typical American diet.”
The Paleo Diet – The Bottom Line
Increasing your intake of whole foods (like vegetables, fruits, healthy fats, and lean proteins) while cutting back on refined sugars, processed foods, and bread can lead to significant health benefits. Deciding to cut legumes, dairy and whole grains is another question. Science shows this can benefit health as long as you make up for lost calcium and carbohydrates by eating the right fruits and vegetables.
There is no “one-size-fits-all” diet. You may thrive on the Paleo Diet while others may feel best on a higher carbohydrate vegan diet. That is why nutrition is ultimately a personal decision, based on what feels right to you. Find the foods that work best for you and, as always, speak with a nutritionist or doctor before making any drastic dietary decisions.