The Paleolithic or "Paleo" diet seeks to address 21st-century ills by returning to the way humans ate more than 2 million years ago. Paleo advocates argue that because our genetics and anatomy have changed little since the Stone Age, we should eat foods available at the time to promote good health. Our forefathers used simple stone tools that were insufficient for growing and cultivating plants, so they hunted, fished, and gathered wild plants for food. Because of a consistent diet of lean meats and plant foods, as well as a high level of physical activity from intensive hunting, they were thought to experience fewer modern-day diseases like diabetes, cancer, and heart disease if they lived long enough.

The Paleo diet, which peaked in popularity in 2014, catered to consumers' growing desire to eat more healthfully and to know where their food came from.

How Does It Work?

The Paleo diet, also known as the caveman or Stone-Age diet, consists primarily of lean meats, fish, fruits, vegetables, nuts, and seeds. Diet supporters emphasize the importance of eating low-glycemic fruits and vegetables. There is disagreement about several aspects of the Paleo diet, including what foods existed at the time, how diets differ depending on region (e.g., tropical vs. the Arctic), how modern-day fruits and vegetables bear little resemblance to prehistoric wild versions and disagreement among Paleo diet enthusiasts about what foods are included/excluded from the diet.

White potatoes, for example, were recorded as being available during the Paleolithic era, but they are typically avoided on the Paleo diet due to their high glycemic index. Because of the emphasis on fresh foods, processed foods are also technically off-limits, but some Paleo diets allow frozen fruits and vegetables because the freezing process preserves most nutrients.

Overall, the diet is high in protein, moderate in fat (mostly unsaturated fats), low-moderate in carbohydrates (restricting high glycemic index carbs), high in fiber, and low in sodium and refined sugars. Marine fish, avocados, olive oil, nuts, and seeds contain monounsaturated and polyunsaturated fats (including the omega-3 fats EPA and DHA).

The following is a list of foods that are generally allowed on the diet:

Fresh lean meats, fish, shellfish, eggs, nuts, seeds, fruits and vegetables, olive oil, coconut oil, and small amounts of honey are all permitted. Because of their high nutrient content, certain root vegetables such as sweet potatoes and cassava may be consumed in moderation.

Whole grains, cereals, refined grains and sugars, dairy products, white potatoes, legumes (peanuts, beans, lentils), alcohol, coffee, salt, refined vegetable oils like canola, and most processed foods, in general, are not permitted.

Calorie counting and portion control are not stressed. To improve overall compliance, some plans allow a few "cheat" non-Paleo meals per week, especially when first starting the diet.

Caveman or Stone-Age Diet