by Dominic Angelino

Paleo, the Caveman diet, is very popular today. That leads many people to consider adopting it as a dietary means to achieve their fitness goals. It makes sense because it’s easy to follow, can be understood as a series of very practical actions, and can work for some people’s goals under certain conditions. Plus, it sounds fun to many people (“Cool! I get to eat like a caveman”), and provides a sort of group identity to those that participate in the diet. But what exactly is the Paleo diet and where does it come from?

Optimized for Evolution?

The name of the Paleo diet points to its origin. It is a dietary style designed to closely mimic the diets of our ancestors from the Paleolithic era. This is where it got the nickname, the “Caveman” diet. The underlying belief system of many of the adherents of the Paleo diet is that humans were bio-evolutionarily primed to eat in a certain way. It should be noted, though, that this conclusion assumes that bio-evolutionary adaptations regarding diet ceased in the Paleolithic era resulting in the typical Western diet today being out of sync with our body’s nutritional needs. This isn’t a well-substantiated claim. It presupposes that the diet of our forebears during the Paleolithic era was an ideal diet for the human body. It also makes the assumption that no evolution has occurred within the human species since the Paleolithic era. Regardless, the specific dietary guidelines that the Paleolithic diet yields are solid when viewed through the lens of the body of scientific research.

The Paleo diet advocates for the consumption of foods that could have been hunted for or gathered during the Paleolithic era. This leads to a diet comprised largely of non-dairy animal products, vegetables, nuts, sweet potatoes, and some fruit. Paleo diets tend to be high fat, moderate protein, and low to moderate carbs (but by no means a ketogenic diet). The specific foods selected within these categories are usually recommended to be organic, or at the very least natural. These selections are prioritized over processed foods (or those with added sugar) whenever possible. Don’t get discouraged though, foods can be combined to make a number of delicious Paleo recipes.
Because of the Paleo diet’s recommendations surrounding animal products, saturated fat intake tends to be very high. Additionally, the limitations placed on food choice can result in micronutritional deficiency without supplementation from something like a multivitamin. It should be noted when supplementing that the bioavailability of micronutrients tend to be lower in their synthetic forms so that less vitamin D (for example) will be absorbed from a multivitamin than from a natural source.

The Good

Paleo dieting has a number of discrete benefits for those with specific fitness goals as demonstrated by a variety of different research studies when contrasted with typical non-dieting food consumption. These range from improvements in blood pressure, glucose tolerance, insulin sensitivity, and blood lipid profiles to the potential facilitation of fat mass loss. These benefits are important for general health and well-being.
High blood pressure, or hypertension, is a cardiovascular disease which has a high comorbidity with several other unwanted cardiovascular diseases. Similarly, low insulin sensitivity often results in type II diabetes mellitus which is a lifelong condition that has a high comorbidity with other undesirable chronic diseases. Anything that can improve these values is doing something right. Research has proven that the Paleo diet can improve both blood pressure and insulin sensitivity.

The same can be said of the decrease in fat mass that can be experienced on the diet. This can largely be attributed to the overall decrease in total daily energy expenditure associated with the Paleo diet. Unprocessed foods, like organic fruits and vegetables, which tend to be lower calorie than typical Western fare along with high-fat grass-fed or pastured meats, which tend to be more satiating, are emphasized within the Paleo community. This frequently results in participants consuming less calories than they would otherwise. This is especially true of those that were not adhering to a strict diet prior to beginning Paleo. Since daily caloric balance is an important component of fat loss and improved body composition, the Paleo diet commonly results in a loss of fat mass. Decreasing fat mass is very beneficial for a number of different reasons and happens to align with most people’s fitness goals so it’s definitely a worthwhile positive of the Paleo diet.

It should also be noted that there can be psychological behavior change adherence benefits to committing to the Paleo diet. A community has sprung up around the Paleo diet supported by legions of devotees. Books, blogs, YouTube channels, and podcasts abound all supporting the Paleo lifestyle. When someone joins a group with a specific uniform mentality and approach to an issue, a group identity can be formed. This makes it easier to stick with the attempted behavior change and can make the process a lot more fun.

The Bad

Though there are a host of benefits to the Paleo approach to dieting, there are also a number of shortcomings that are worth addressing. Much of the approach to and reasoning behind dieting in this way is based on a narrow view of nutrition. Elements of food such as gluten and lectins are labeled as “bad” in the Paleo diet and thereby are used to justify not consuming foods that have them. This view, as with most diets like this, ignores the hundreds of other scientific studies that demonstrate beneficial ways to consume and use foods that are written off as off-limits by diets like Paleo.

There are also hundreds of studies placing subjects on a non-Paleo diet that included foods like, for example, starchy carbohydrates (think bread, pasta, rice, white potatoes, and oats) while the participant lost fat mass, gained muscle mass, got stronger, and achieved other meaningful adaptations. For example, one study by Golay (1996) demonstrated that high carb diets without controlling for carb source were able to produce significant decreases in fat mass and waist to hip circumference. Many other studies have not controlled for carb source and have found positive adaptations regardless. Foods are inherently very complex. Each food comes with pluses and minuses. Higher carb diets with grains, as an example, can lead to greater performance during workouts which facilitates even greater long-term adaptations than a low carb diet. Carbs even help mitigate peri-workout muscular catabolism and help promote muscle protein synthesis when combined with adequate protein intake.

Things like milk, which in the Paleo world is a gray area, have a high concentration of the amino acid leucine that is a major stimulus of muscle protein synthesis. This can be missing in the Paleo diet. Even chocolate milk has been substantiated to be one of the best ways to replenish glycogen stores in the body and can help improve performance at the gym.

It’s usually not advocated to track calories or specific macronutrients (like protein, carbs, or fat) in the Paleo diet. This can be detrimental. The primary driver of fat loss on any diet is calorie intake. While the relatively high fat intake on the Paleo diet contributes to satiety, which naturally limits caloric intake, without tracking calories, it’s possible to overconsume calories on the Paleo diet if not careful. Likewise, macronutrient balance is also important. Absent an accounting of macronutrient intake, a deficiency could develop. Finally, because animal sources of food tend to be high in saturated fat, LDL cholesterol (the bad kind) is apt to increase over time in those consuming too much.
Overall, the Paleo diet has shown success in facilitating positive health outcomes as opposed to not dieting and it can definitely be a useful tool toward promoting better health. The support system and easy to follow, practical guidelines it provides are very helpful given the thing that matters most in selecting a diet is someone’s ability to stick to it. Paleo is a bit easier to start doing and stick with than some of the other alternatives.

But its approach is a bit singularly focused and is less optimal than diets that would be recommended by professional organizations like the National Strength and Conditioning Association (NSCA), American College of Sports Medicine (ACSM), or US Department of Agriculture (USDA) whose recommendations are based on a holistic view of all available science. The Paleo diet stumbles onto a few successful mechanisms for positive health adaptations substantiated by science but it seems the Paleo community misattributes the reasons for these adaptations. This is evident in examining claims related to fat loss. Fat loss, as demonstrated by Golay (1996) and many others is primarily attributable to total caloric intake. Other studies have also demonstrated that the effects of caloric intake on changes in body composition are modulated by macronutrient consumed, like in Abete (2010). Eating a food simply because it was eaten thousands of years ago doesn’t make it an ideal tool for achieving one’s fitness goals. There are more nuanced reasons for adaptations.

Does the Paleo Diet Work?

The reasons that this diet, as well others, work is that they rely on the same basic scientific fundamentals for success. Fundamentally certain caloric intakes lead to fat loss, macronutrients have specific effects on the body, and micronutrients promote proper organ function. Many fad diets out there promote foods that are micronutritionally dense (like vegetables), food that has a good amount of fiber (like sweet potatoes), and low calorie foods. They just end up getting to those recommendations through misattribution or round-about ways. Many diets out there mis-attribute the exact reason for success though which is why they make conflicting claims yet still produce results. Though it should be noted that there isn’t a large body of scientific evidence supporting use of the Paleo diet more so than other diets that are already well supported. Many of the Paleo diet’s foundational claims can be contested by other studies disputing the context of the basic science it’s predicated on. For example Phillips (2009) and Lunn (2012) both demonstrate the very clear effectiveness of milk and milk related products as a means to supplementing ones fitness goals. They aren’t alone, a ton of other studies out there validate benefits of foods otherwise outlawed by the Paleo diet.

In general, the most realistic diets are those that view foods holistically as a mix of good and bad elements, rather than as black and white, permitted or not permitted. Reality is more nuanced. That’s not to say the Paleo diet shouldn’t be followed. It’s like a lot of diets out there. It has its flaws and overlooks some things, but it can get the job done if done right. Many popular diets are like that. Don’t feel as if you’re forced to follow a Paleo diet since there are many other options out there that do work, but also don’t feel as if you can’t start doing it either. It can help you reach some of your goals. If you stick to it and like it then that’s all that matters, right?

Should You Eat Like a Caveman?

There’s no harm in trying the Paleo diet for a bit if you’re interested, and if it doesn’t work for you just move on. But if it does, then you’ve got yourself a means to improving your health. There may be some elements of the diet that can detriment your health (e.g. having a high saturated fat intake risk elevating LDL cholesterol and total cholesterol), but the number of benefits can outweigh the most clear downside. At the end of the day, going on a diet that helps you lose fat mass and be happier will have more health benefits than detriments. But if you’ve already been diagnosed with cardiovascular disease or are at high risk, it may be worth it to consider checking out other diets that better suit your needs.

References:

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