Today, you’d be hard-pressed to read a health magazine or step into any gym without hearing something about paleo and ketogenic diets.

Many people follow these diets because they want to lose weight or improve their overall health. Yet since both diets are so popular, you may be wondering how they differ.

Here is a detailed comparison of the paleo and keto diet, including which is best.

Paleo vs. Keto

The paleo diet, sometimes referred to as “the caveman diet,” is based on the principle that eating foods that were available to early humans will promote optimal health.

One of the fundamental theories behind the paleo diet is that modern food systems, production and processing techniques are damaging to human health.

Thus, if you adjust your eating style to mimic that of Paleolithic hunter-gatherers, you will better support your body’s natural biological function, improving digestion and health.

Paleo eliminates grains, legumes, processed sugar and most sources of dairy.

The main foods permitted on the paleo diet include:

  • Meat and fish
  • Eggs
  • Nuts and seeds
  • Fruits
  • Vegetables — except corn, which is a grain
  • Unrefined fats and oils, such as coconut oil, olive oil, avocado oil, lard, tallow, ghee/butter
  • Minimally processed sweeteners, including raw honey, maple syrup, coconut sugar, raw stevia

For most, paleo is about more than just a diet.

There is also a strong focus on lifestyle practices, the environmental impact of food choices and total body wellness within the framework of the paleo philosophy.

Summary The paleo diet is an eating plan that emphasizes whole foods and eliminates grains, legumes and processed foods in order to improve health. The diet also has a lifestyle component that focuses on wellness practices and exercise.

Most tissues in the human body prefer using the glucose from carbohydrates for energy.

Ketosis is the metabolic state in which your body uses calories from fat, instead of carbs, to create the energy needed to carry out its normal functions ().

The keto, or ketogenic, diet aims to induce ketosis through the calculated adjustment of dietary macronutrients, namely carbs, protein and fat.

The keto diet macronutrient breakdown looks something like this:

  • Fat: 60–80%
  • Protein: 20–30%
  • Carbohydrates: 5–10%

In comparison to a “standard” diet, the macronutrient distribution of the keto diet is shifted significantly in favor of fat, with moderate protein and very few carbs.

The purpose of achieving ketosis with this diet plan is to induce the metabolic breakdown of fat in your body. Thus, it’s imperative that macronutrient intake is tightly controlled, as otherwise you risk throwing your metabolism out of ketosis.

One of the main reasons that the keto diet has gained recent popularity is because of its potential to help you lose weight and improve blood sugar control ().

Summary The keto diet is an eating plan that focuses on controlling the macronutrient distribution of meals in order to shift the body’s dependence from carbs to fat for energy.

Although they are distinct, paleo and keto diets share many characteristics. Below are some of the main ideas these diets have in common.

Both Emphasize Whole Foods

Fundamentally, both paleo and keto diet plans are intended to rely on whole-food sources of nutrients.

A whole food is a food that has undergone a minimal amount of processing by the time it gets to your plate.

Both keto and paleo diets strongly encourage eliminating all ultra-processed foods and replacing them with whole foods like fresh vegetables, meat, fish and nuts.

This is especially evident with the exclusion of processed fats, oils and sweeteners in both paleo and keto “rule books.”

Both Eliminate Grains and Legumes

Though for different reasons, both paleo and keto diets strongly discourage eating grains and legumes.

For the paleo crowd, this elimination is largely based on the fact that grains and legumes were not likely part of early human diets and they contain antinutrients.

Antinutrients are compounds, such as lectins and phytates, that can be found in some plant-based foods. They interfere with your body’s ability to absorb minerals and nutrients and may cause digestive distress when eaten in large quantities ().

On the other hand, research suggests that there may also be benefits to eating foods with these compounds ().

The keto diet also eliminates grains and most legumes, but this is because of their carbohydrate content.

Grains and legumes contribute a significant amount of carbs to the diet. If you eat them while following the keto diet, you risk throwing your body out of ketosis.

Both Eliminate Added Sugar

Keto and paleo diets strongly discourage the intake of added sugars.

For both diet plans, this largely falls under their shared message of avoiding heavily processed foods in general.

However, paleo dieters are a bit more flexible with this rule, as unrefined sugar sources like honey and maple syrup are still permitted.

Keto, on the other hand, doesn’t allow any added sugar sources, refined or not, due to the high carb content of these foods.

Both Emphasize Healthy Fats

In line with their shared goal of achieving optimal health, both paleo and keto diets encourage the intake of unrefined, healthy fats.

Both diets recommend moderate-to-liberal amounts of olive and avocado oils, nuts, seeds and fish. These foods are known to benefit heart health because of their poly- and monounsaturated fat content ().

Both diets also discourage the use of heavily processed fats, such as trans fats, which are detrimental to health when consumed regularly ()

Keto places very heavy emphasis on fat in general, as it is the cornerstone of the entire diet. Paleo, while not necessarily a high-fat diet, uses this recommendation to support overall health.

Both May Be Effective for Weight Loss

One of the primary reasons for the popularity of keto and paleo diets is the notion that they will promote weight loss.

Unfortunately, there is limited research available for how effective these diets are for sustained, long-term weight loss. However, some short-term research is promising.

A small study of postmenopausal, obese women following the paleo diet showed a 9% weight loss after six months and a 10.6% loss at 12 months. No additional significant change in weight was seen at the 24-month mark ().

One review of research on low-carb, high-fat (LCHF) diets, such as the ketogenic diet, indicated that short-term weight loss can occur when switching to this style of eating ().

This may have been because a high intake of fat usually leads to a decrease in appetite and fewer overall calories consumed. It may also be that the process of ketosis is leading to more efficient elimination of the body’s fat stores. The exact reason is still unclear.

Ultimately, more research is needed to determine a clear causal relationship ().

Summary The keto and paleo diets share a lot of similar food restrictions and rules, though often for different reasons.

One of the key differences between the paleo and keto diets is the ideological message, or lack thereof.

The paleo diet places a heavy emphasis on lifestyle choices beyond just the diet. It explicitly encourages a specific style of exercise and mindfulness in daily activities to accompany the dietary pattern.

One of the mainstays of the paleo lifestyle is to incorporate short, intense periods of exercise into your routine. This style of physical activity is thought to reduce the stress that may accompany longer workouts.

Other methods of stress reduction encouraged on the paleo diet include yoga and meditation.

When paired with the diet, these lifestyle practices are intended to support the total wellness of your body and mind, leading to better overall health.

While the paleo diet regimen is very specific, it doesn’t place any emphasis on macronutrients at all. You are permitted to eat as much protein, fat and carbohydrates as you want, provided you’ve chosen them from the set list of “allowable” foods.

Keto, on the other hand, doesn’t have an associated ideology or lifestyle component. While it does encourage choosing healthy food sources, the main focus is macronutrient distribution.

Any other implemented lifestyle changes alongside the keto diet are the up to the individual and are not part of the diet regimen itself.

Summary The paleo diet encourages certain activities outside of following the diet, such as exercise and mindfulness, and it places no limits on macronutrients. Keto only requires that you stay within a set range of carbs, protein and fat.

Although paleo does restrict some carb sources, it isn’t necessarily a low-carb diet in the same way keto is.

Because paleo does not emphasize macronutrients, your diet could theoretically be very high in carbs, depending on which foods you choose to eat within the specified parameters.

Because grains, refined sugars and legumes aren’t permitted, the carb sources on the paleo diet are somewhat limited but not eliminated. Paleo still allows carbs from groups of whole foods such as fruits, vegetables and unrefined sweeteners.

Conversely, the keto diet restricts all rich sources of carbohydrates, including starchy vegetables, most fruits, grains, sweeteners and most legumes.

Due to the fact that total carb intake must remain below a certain threshold to maintain ketosis, many high-carb foods, regardless of their source, simply don’t fit into a keto diet.

Summary Keto restricts your carb intake, while paleo allows for many whole-food sources of carbs, provided they fall into the permitted food categories.

Keto permits, even encourages, eating many dairy foods. High-fat dairy in the form of heavy cream, butter and unsweetened full-fat yogurt are mainstays of many ketogenic diet plans.

Other dairy products, like ice cream or milk, are prohibited on the keto diet but this is mostly due to their low fat-to-carb ratio.

Soy foods like tofu, tempeh and soybeans are allowed on the keto diet as long as they fall within your specified macronutrient allotment. Soy milk, however, is usually discouraged.

Paleo, on the other hand, doesn’t allow for any soy and restricts almost all dairy.

Grass-fed butter is the one permitted dairy product on the paleo diet. However, there is some disagreement within the paleo community about whether or not this allowance is truly in line with the paleo ideology.

Additionally, paleo does not allow for any soy products because they fall into the legume category of foods.

Summary Keto encourages eating high-fat dairy foods and some soy, provided that they fit within the recommended macronutrient range. Paleo doesn’t allow dairy or soy, with the exception of some butter.

Both paleo and keto diets can be healthy options, depending on how they are implemented and what they are used for.

In a side-by-side comparison, the paleo diet is a healthier option for most people.

Paleo allows for more flexibility of food choices and more options for obtaining the wide array of nutrients your body needs on a daily basis. It also encourages an overall healthy lifestyle.

Freedom within food choices makes paleo easier to maintain long-term with less potential to be socially isolating.

Keto does not suit everyone and may be beneficial as a treatment method for some health conditions.

Also, about a quarter of the population is sensitive to dietary fat and should therefore not be on such a high-fat diet ().

Keto is more difficult to maintain because of the strict compliance needed to achieve ketosis. It requires careful planning and can be less adaptable to varied social situations.

Keto’s lack of flexibility can also make getting adequate nutrients a challenge because of the limited options.

Summary Both paleo and keto diets have the potential to be healthy, but paleo is more likely to offer a wider variety of nutritious options. Keto can be difficult to maintain and may not be well tolerated by some people.

The ketogenic diet is characterized by its high fat and very low carbohydrate content. It may be effective for weight loss and blood sugar control.

The paleo diet emphasizes eating whole foods that were thought to be available to humans in the Paleolithic era. It also encourages exercise and other wellness practices.

Both diets have the potential to positively impact your health when appropriately planned.

However, long-term research regarding safety and efficacy of these diet plans is lacking and some of the restrictions can be difficult to maintain.

For most people, the paleo diet is a better choice because it has more flexibility with food choices than keto, which makes it easier to maintain long-term.

At the end of the day, the diet that works long-term for you is the best choice.