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What’s the Difference Between the Paleo and Keto Diets? (video)

One promotes whole foods, the other low-carb foods

One promotes whole foods, the other low-carb foods

Weight loss is an ongoing challenge for many people, and popular diet plans are constantly changing. Over the past few years, two of the most talked-about weight-loss plans have been the keto diet and the paleo diet.


In this video, San Diego Health host Susan Taylor talks with Samantha Harris, MD, an endocrinologist at Scripps Clinic Del Mar, who specializes in weight management, about these weight-loss approaches and who might benefit most from them.

Keto diet: low carbs and ketosis

A very low-carbohydrate eating plan, the keto diet aims to cause the body to start breaking down fat for fuel. When fat breaks down, it produces ketones, which are used instead of carbohydrates for energy. This is known as being in the state of nutritional ketosis.


“There are several ways to tell if you’re in ketosis,” says Dr. Harris. “There are mechanisms that can test your breath, your blood or your urine for ketones, but you may notice that you feel thirstier, urinate more frequently, feel a bit nauseated, or have a metallic taste in your mouth.”


There are various keto plans, but all promote very low-carbohydrate foods, such as beef, chicken, fish, eggs, nuts and some cheeses, along with fats like avocado oil, mayonnaise and butter. Fruits and vegetables are allowed if they are low in carbohydrates, such as berries and spinach.


Keto diets restrict foods high in carbohydrates, including simple sugars, processed sugars, juice, breads and rice. Starchy fruits and vegetables like tropical fruits, bananas, corn and potatoes are minimized.


Dr. Harris says a keto diet can be a good choice for people who are highly motivated and enjoy the food choices, but certain people should not do it.


“Women who are pregnant or nursing really should not be in the state of ketosis, as it potentially has some effects on the developing fetus or a nursing child,” she says. “And for anyone with a history of eating disorders like binge-eating disorder or anorexia, cutting out carbohydrates can make eating disorders worse in the long run.”

Paleo diet: eat like a caveman

The paleo (paleontology) diet, affectionately known as the caveman diet, is based on the way our ancestors thousands of years ago would have eaten. It focuses on whole unprocessed foods, such as animal proteins and plants but excludes dairy and grains. Lean cuts of grass-fed meats are recommended over grain-fed meats and high-fat cuts.


“The health benefits of eating whole foods that are high in vegetables and low in sugar are numerous,” says Dr. Harris. “One, it can help promote weight loss, and when people lose weight, their general health and well-being improves. They lower the risk of cancer, high blood pressure, heart disease, diabetes, depression, sleep apnea, dementia. It goes on and on.”


An offshoot of the paleo diet is the pegan diet, which is a vegan version of the paleo plan. No animal products are allowed; protein comes from plant-based foods like nuts and beans.

Diets vs. long-term changes

Any diet that limits calories and is fairly easy to stick to can help people lose weight, but the best results come from making long-term changes in your eating habits.


“It really should be a permanent change as opposed to a temporary diet, because if someone eventually goes back to eating the way they used to, they run the risk of regaining the weight that they had lost,” says Dr. Harris.


“Any type of eating plan really depends on your personal preferences, what you enjoy eating and what you think you could continue in the long run, at least most of the time. Choose something that’s simple and safe, but most importantly, sustainable for you.”