Is the Paleo Diet for You?

If you’ve ever sat in front of the chimpanzee exhibit at a zoo and watched them in action, you probably didn’t leave bragging about how much humans are like our ape ancestors. But the truth is, only one percent of our biological makeup has appeared since we split from the great apes seven million years ago, meaning our physiology and its workings are still very similar to what they were in our ancient ancestors. And that’s the premise behind the “Paleolithic diet,” that eating like our hunter-gatherer predecessors is more aligned with the workings of our bodies and can prevent “diseases of civilization” such as diabetes, heart disease, asthma and a host of other conditions.

Proponents of the Paleo diet don’t suggest humans need to hunt for meat or gather roots and berries in order to be healthy, but they do recommend we stick to eating only foods that were available to pre-agricultural peoples. That means giving up dairy, sugar, processed meats, legumes and grain products, and replacing them with lean meats like birds and fish, starchy roots, nuts and seasonal vegetables and fruits. Paleo diet–approved foods are high in soluble fiber, antioxidants, phytochemicals, omega-3 and monounsaturated fats, and low-glycemic carbohydrates—the kind of foods that allowed our ancestors to have strong, lean and active bodies.

The Slowness of Change

It was only around 10,000 years ago that humans started settling down, moving away from a hunter-gatherer lifestyle and cultivating grains and legumes. That may sound like a long time, but not in terms of biological adaptations, says the “grandfather” of the Paleo diet, S. Boyd Eaton, MD. In his book The Paleolithic Prescription (Harper & Row, 1988) Eaton explains that “. . . tens of thousands of years are often necessary for minor changes to occur, hundreds of thousands or even millions for more significant changes.” In other words, our bodies have not yet adapted to eating these crops, not to mention the sugar, dairy, oils and refined flour that the modern diet includes.

So, what happens when you eat foods you aren’t well adapted to? “Good health can be expected when you feed your body the foods to which it has genetically adapted. Conversely, when we feed our bodies food that we have not adapted to, dyspepsia, degeneration, and disease will follow,” says Doug Willen, DC, author of Quantum Paleo (Fight Productions, 2012). For example, grains contain anti-nutrients like lectin and gluten, both of which have been linked to inflammatory reactions and digestive diseases such as leaky gut. What’s more, the high Glycemic Index ratings of grains, including wheat, rye, barley, rice, oats and corn, produce a rise in blood glucose levels. Repeated occurrences of such spikes have been associated with diabetes, obesity and cardiovascular disease.

The story is similar with legumes: our hunter-gatherer ancestors didn’t consume them because they needed to be cooked in order to be edible. Legumes also contain lectins as well as phytates, which inhibit nutrient absorption and cause inflammation. And it’s not just lentils we are talking about here; a strict interpretation of the Paleo diet suggests one also avoid all beans, peanuts, soybeans and chickpeas.

It is no surprise that sugar is completely off limits, as are trans fats. Dairy is a little more complicated, as it is thought to have been available to hunter-gatherers intermittently. However, the majority of Paleo advocates suggest avoiding it, since most people are deficient in the enzymes that break down the sugars in dairy.

What Can You Eat?

There seems to be a range of Paleo-diet philosophies, some more lenient, which allow the consumption of cultured dairy products, and some super strict, even forbidding the consumption of certain nuts like cashews. However, all center the bulk of their meals around vegetables, especially root vegetables like turnips and parsnips—but potatoes are off-limits. Lean protein sources, including chicken, turkey and fish, as well as game and organ meats are encouraged; conservative amounts of grass-fed beef are okay, but fatty cuts of meat and anything processed are out—yup, that means your beloved hot dogs and bacon.

Paleo folks use nuts and seeds as sources of good fat; eggs provide protein; and fruits add vitamins and antioxidants as well as a touch of sweetness to the diet. The harder fruits like apples and pears, along with berries, are the ones most recommended. And avoid fruit juice: you need the fiber in the skin and pulp of fruits to help “time-release” the sugars in your body. Keeping blood sugar levels steady is one of the Paleo diet’s biggest claims to fame.

What the Science Says

Such improvements in blood sugar levels and weight loss have garnered the Paleo diet quite a public following, and a small group of researchers in Sweden have begun to test the premise that pre-agricultural “Paleolithic” diets might be the secret to improving modern human health.

For example, in a 2007 clinical trial published in the journal Diabetologia, 29 diabetic and prediabetic volunteers with heart disease were put on one of two diets: a “Paleolithic” diet focused on lean meat, fish, fruit, vegetables, starchy roots, eggs and nuts; or a “Mediterranean” diet focused on whole grains, low-fat dairy, vegetables, fruit, fish, oils and margarine. Over the 12-week study, both groups lost body fat and showed improved markers of diabetes; however, those in the Paleo group lost 70 percent more body fat, and showed a significantly greater normalization of blood sugar.

So, does that mean we should all be eating a strict hunter-gatherer diet? Not necessarily, as each person carries a specific set of genetic adaptations as well as their own food sensitivities. Everyone is biochemically individual. One way to find out if it’s right for you is to try it for 21 days and see how you do. Go ahead and channel your inner caveman.