There are at least 100 types of different diets to choose from in 2020, but some are buzzier than others. Right now, you’re probably hearing a lot about the paleo and keto diets, which for some people have become more of a lifestyle than a short-term diet. If you’re looking to switch up your routine and try something new with the goal of losing weight, should you be trying either of these diets? We asked the experts to break down the differences between paleo versus keto to find out which one is better for weight loss and whether or not either is sustainable long term.
What is the paleo diet?
The paleo diet is a way of eating foods that were available in the Paleolithic Period (dating back to roughly 10,000 B.C.). This diet, then, involves mostly eating meats, fish, eggs, nuts, seeds and fruit, among others. You won’t consume grains, refined sugars, legumes, dairy, coffee or alcohol—among others—when following this diet.
“Paleo is essentially a whole food diet that removes some of the potential allergens you may not deal well with that have made their way into our food supply over time, like a number of grains, certain nuts and milk,” explains nutritional biochemist Shawn Wells, MPH, RD, LDN, CISSN, FISSN. “Essentially, at its core, it is a whole food diet.”
According to the Harvard T.H. Chan School of Public Health, cavemen are believed to have experienced less of illness prevalent today, such as diabetes and heart disease, in part because their diets focused on lean proteins and plants. However, there is some question as to its effectiveness as our lifestyles have dramatically changed over the millions of years since.
“It is true that both animals and we as human species adapt over time, so can we really say that the “paleo diet” has the same effect on us that it had on cavemen?” asks Silvia Carli MS, RD, CSCS, LD, a sports dietitian with 1AND1 Life. “And were the cavemen really feasting on much meat every day?”
According to nutritionists at the University of California, Davis, while meat was a large staple and this protein accounted for much of their caloric intake, plants still made up the bulk of their diets. The problem with eliminating certain foods is it can leave an imbalance, especially as “saturated fat and protein can be consumed far above recommended levels.” They add that people who choose the paleo diet may experience calcium and vitamin D deficiencies, so supplementation may be necessary.
Studies have also found that caution should be taken when following what is a modern Paleolithic diet in the long term, especially as our gut microbiome can vary based on where we live. Other studies that have been done testing the paleo diet against cardiovascular disease risk factors and chronic disease markers both need further testing and larger sample sizes before conclusive benefit can be determined.
Instead of the high protein intake that is experienced on the paleo diet, the ketogenic diet—known as keto—focuses on high fat and low carbohydrate, with a moderate focus on protein. According to Carli, this diet was originally created in the 1920s for treatment of seizures in children. The keto diet forces the body to utilize other sources of fuel besides carbohydrates and sugars; the alternative fuel source is what is thought to help reduce seizures, epilepsy and more.
“There are some variations to it, but the typical ketogenic diet consists of 70% fat, 5% carbs and 25% protein,” explains Carli. “Basically, the carbs—the body’s preferred energy source—are lowered enough to force the body to switch the type of fuel from carbs to ketones, which are a byproduct of fats.”
These ketones are made by the liver and, as researchers at the University of California, San Francisco explain, are created at night and during times of fasting. Some people, then, will also combine the keto diet with intermittent fasting in order to force the body to go into a state of ketosis faster, with the goal of burning more fat.
“Now, we don’t do as much labor, we don’t work out as much, we are more sedentary, we eat more often, we eat high-glycemic carbohydrates and we certainly don’t fast,” admits Wells. “All of those things add up to us only using glucose for fuel in our bodies and rarely ever getting into a ketogenic state. But if you were to go back in time, we were more metabolically flexible and could tap into either fuel source very well. Now, because we are only using glucose, we tend to get into these insulin resistant, glucose intolerant states, which causes inflammation, glycation (blood sugar damage) and oxidation, and it ages us more rapidly.”
With the keto diet, you can expect to eat meats, eggs, sausage, cheese, fish, nuts, butter and fibrous vegetables. There are typically less fruits and vegetables consumed than in the paleo diet, especially as the focus is to eat mostly fats that you’ll find in foods such as olive oil, grass-fed beef, nuts and avocados. While grains contain good fats, they are avoided on the keto diet because they are rich in carbohydrates and delay the body reaching ketosis.
“There are no long-term studies, but the ketogenic diet seems to help reduce hunger and control appetite through elevated protein consumption and possibly some ketones mechanism of action,” adds Carli. “The ketogenic diet might also have a place in improving insulin sensitivity in the setting of diabetes and obesity. Patients deciding to undergo this regimen need to be followed by [a doctor].”
Paleo vs keto
To be upfront, both paleo and keto can be difficult to follow because of our current lifestyles and what is available in grocery stores. Finding minimally-processed foods, high-quality meat and fresh fruits and vegetables can be costly. It isn’t impossible, but does require some restriction and giving up specific food categories and groups. If it sounds hard, that’s because it is—Wells explains that processed foods are created to be addictive.
“[You want to get] away from processed foods—now called ultra-processed food—that is really engineered to not only look good, taste good and fire off dopamine and serotonin, but really [also] overrides satiety signals,” he explains. “You’re overeating a lot of this food. For example with soda, they make it so that it has a certain flavor and sweetness on the front end but nothing on the back end so you want to keep drinking it. So when you go back to whole food and remove allergens that can cause inflammation, you can have a great baseline of nutrition—food as it’s meant to be. That seems like a logical place for everyone to be.”
Experts suggest that paleo may be easier for beginners to stick to longterm because it allows for more flexibility and is easier for beginners to stick to. Also, some doctors note that the keto diet can result in initial weight loss, but it often plateaus or comes back. Because of this effect—and how restrictive the diet is—it can be hard to follow longterm.
“Extremes rarely ever work in the long run and the ketogenic diet is an extreme regimen,” notes Carli. “The paleo diet allows for whole food carbs and more flexibility of choices as there’s no limit on the quantity of carbs but only quality.”
When it comes to considering the two in weight loss, a recent study confirmed that the weight loss achieved from the keto diet isn’t sustained in the longterm. As for the paleo diet, in a study that compared it to the Mediterranean diet, differences in weight loss weren’t significant.
Paleo vs keto for weight loss
When choosing a new diet where the main goal is weight loss, the one that will be most successful is the one that you actually enjoy. This often means not restricting certain foods or even thinking about things in terms of “cheats.” If your way of eating is considered a lifestyle versus a diet, you’re more likely to have success and be able to follow it for life. Wells explains that getting into an undesirable state of health doesn’t take 8-12 weeks, so you can’t expect a diet that only takes 8-12 weeks to work longterm. Instead, he recommends making small changes.
“The best place for everyone to start that is super simple is to eat whole food and avoid processed food,” instructs Wells. “The next step is trying to get yourself off of sugar. Sugar is something that is so addictive and creates so much impulse! I would also try to start some kind of exercise, two or three times per week, along with taking a walk around lunchtime or after dinner. Even just 10 minutes of exercise has been shown to improve your blood sugar levels.”
Wells also recommends giving fasting a try. “You don’t have to do extended fasting or intermittent fasting—just starting only [eating in a 12 hour window] will stop you from snacking as much and having a nighttime meal,” he says. “These are good places to start to dial in lifetime habits.”
When starting a new approach to how you’re eating, one professor of medicine at Stanford University recommends following a more rewarding play on the paleo diet that is less restrictive, adding small amounts of dairy and some variety of whole grains. He states this would be just as healthy (and can provide some of the calcium and vitamins that experts say that those on the paleo diet may have deficiencies in).
“What works for weight loss is ultimately caloric deficit,” concludes Carli. “This can be achieved with any method that is most suitable for the subject desiring weight loss. We are all different in body type, activities performed, metabolism, sex, age, lifestyle and so much more than the approach of ‘one size fits all’ could never be accurate.”
Next up, find out how keto compares to Whole30.