The Paleo Diet: How It Works, What to Eat, and the Risks

By Beth W. OrensteinMedically Reviewed by Kelly Kennedy, RD
Last Updated: 12/19/2019

Obesity, heart disease, and diabetes: These are just a few of the health conditions that proponents of the Paleolithic diet, or caveman diet, blame on our sedentary lifestyles and modern diets, which are loaded with sugar, fat, and processed foods. Their proposed solution? Cut modern foods from our diet and return to the way our early hunter-gatherer ancestors ate.

To get an idea of what that means, we turned to the experts, including Loren Cordain, PhD, a professor emeritus at Colorado State University in Fort Collins, Colorado, and the author of The Paleo Diet; Erin Holley, RD, of Ohio State University Wexner Medical Center in Columbus, Ohio; and Lona Sandon, PhD, RD, an assistant professor of clinical nutrition at the University of Texas Southwestern Medical Center in Dallas.

For starters, to be and stay healthy on the paleo diet, Cordain says that you’ll need to exercise regularly while following a strict diet comprised only of foods that can be hunted and gathered.

In its purest form, the paleo diet allows you to eat only those foods that humans ate when they first roamed the planet millions of years ago.

The diet can improve your health by eliminating high-fat and processed foods that have little nutritional value and too many calories. This plan emphasizes loading up on fruits and vegetables that are bursting with healthy vitamins, minerals, and fiber, which fills you up faster so you eat less, helping curb weight gain. (1)
You’ll lose weight because any time you restrict entire food groups, your calorie intake tends to be lower, Sandon says. And whenever you burn more calories than you consume, you'll have weight loss, she says. (2) The focus on lean protein, fruits, and vegetables over calorie- and sodium-rich processed foods can also contribute to weight loss, though she also points out that the paleo diet wasn’t created to be a weight loss diet. (3)

Note that though nuts and seeds are allowed on this diet, they can be high in calories, and people who want to lose weight will have to limit consumption of them.