Before I go tearing the paleo diet apart, I do want to point out the positives of the diet. First, it encourages the consumption of non-processed whole foods. Second, it encourages you to eat fruits, vegetables, nuts, and seeds. Specifically, it suggests that 35-45% of your daily calories come from fruits and vegetables. That's fantastic, or I guess I should say that's 45% fantastic?
Anywhere you read about the paleo diet, you see that one of the major principles is to eat a low carbohydrate diet. The reasoning behind this is said to be that keeping carbohydrate intake low, will keep insulin levels low, and ultimately reduce inflammation in the body. For those that don't know, insulin is released when the glucose levels in our blood spike. So, insulin is released to control our blood glucose levels. The more insulin, the more inflammation. So, the more foods you eat that spike blood glucose levels, the more insulin is released, and thus the more inflammation and ultimately disease.
What doesn't make sense about the paleo diet is, what we associate with high carbohydrate foods, namely grains and legumes, do not increase insulin levels in the body. The whole reason you eat meat and fish on the paleo diet is because it is high in protein and low in carbohydrates, and thus won't cause a spike in insulin. But meats are exactly the foods that raise insulin levels. And I'm not talking just red meat either. Beef, chicken, and pork all result in similar increases in insulin.
In a study comparing an apple, a bowl of oatmeal, a plate of pasta, beef, and salmon, what would you expect the largest insulin spike from? Most people would say the "high sugar" or "high carb" foods like the pasta or the apple. However, the meat, followed by the piece of salmon, resulted in the highest amounts of insulin. In fact, meat consumption causes as much of an insulin spike as eating straight up sugar!
So what do you do if you want to bring insulin levels down? You should actually consume more carbs (in the form of whole plant foods, not processed junk foods). A 1990 study showed that when you double a person's carbohydrate intake (in the form of grains, legumes, fruits and vegetables), their insulin levels go significantly down, not up.
So if low insulin levels is one of the major cornerstones of paleo, then the paleo crowd should in fact be preaching a plant-based diet rich in high carbohydrate foods, right? In countless studies comparing the diets of vegetarians and meat eaters, vegetarians have consistently lower insulin levels. I'm not talking just a small difference either, I'm talking half the insulin levels of meat eaters.
In a 2014 study done by the International Journal of Exercise Science, participants were taken and put on a paleo diet and on a Crossfit regimen. In almost all cases, when you start working out more and lose some weight, your LDL levels go down. But all the participants, even the ones that began the study with very healthy LDL levels, saw an increase in LDL due to the diet in just 3 weeks.
The whole point of exercising is to decrease your chances of chronic disease, but even with a high intensity workout regimen like Crossfit, the paleo diet still increased LDL levels. So, in terms of decreasing your chances of cardiovascular disease and other chronic diseases (another main objective of the paleo diet), the paleo diet literally negates the benefits of intense regular exercise.
Now, if you take a person and put them on a whole food plant-based diet (what most would consider a "high carb" diet) and have them go for a walk every day over the same time period (3 weeks) their bad LDL cholesterol levels will drop 20% and their insulin levels will drop 30%! This was demonstrated in a 1992 study, and continues to be shown.
So what's the big picture here? The paleo diet might not be so great due to the large amounts of meats it recommends, which undermines the whole concept of the diet: low insulin, low inflammation.
What sounds better to you - eating a whole food plant-based diet and taking a nice leisurely stroll every day or busting your ass trying to complete your Crossfit WOD and eating a paleo diet that negates the cardiovascular benefits of you busting your ass?
Why not do some Crossfit AND eat a whole food plant-based diet? Now we're talking.