3 Reasons Not to Trust the Paleo Diet

By Joel Fuhrman, MD, Medically reviewed by a board-certified physician 
Updated on February 03, 2020

Is it smart to eat like a caveman? The short answer is: No.

Certainly, humans were not eating processed foods loaded with sugar, white flour, and oil during the Paleolithic period, but modeling our eating habits after those of our ancestors ( in a specific time frame or specific region of the earth) isn’t the way to arrive at an optimal diet. Early humans were not eating a nutritionally complete, perfect diet. They were eating whatever food they could to avoid starvation.

Debunking the Paleolithic Diet

The available plants and animals for food would have differed based on geographical area. Details about the animal to plant food ratio of true Paleolithic diets are still unclear and tremendously variable. It also maybe be irrelevant, since the development of the primate and early human digestive tract and immune system occurred over a much broader period where primates were in a more limited distribution. The modern Paleo diet has morphed into an opportunity to justify eating meat as a major calorie source. Eating plates and plates of meat to lose weight or improve health sounds too good to be true because it is; it’s more than unhealthy, it’s disease-promoting.

These types of diets tend to surface every few years and are often hailed as a new trend, but they are just the same old diets called by new names: the Paleo diet is not much different from the other high-animal protein diets that came before it, like Atkins, South Beach, Dukan, and Sugar Busters. They all promote the same formula for weight loss: excessive amounts of protein in the forms of animal-derived foods like meat, fish, and eggs. Often, they have the potential to crowd out more healthful foods like vegetables, fruits, beans, nuts and seeds, unnecessarily limiting nutritional variety and phytochemical richness.

Proponents of these diets sometimes may not consider the scientific evidence that eating large quantities of animal products is a risk to health and longevity. A diet high in animal protein and low in carbohydrate—the centerpiece of the Paleo diet—has been associated with an increase in the risk of death from cancer, cardiovascular disease, and all causes. This has held true even for naturally-raised meats.

Considerations for Not Being Paleo

To put an end to the belief that the Paleo way of eating is good for you, here are three reasons why these diets should not be followed:

1- Higher IGF-1, higher cancer risk: Regardless of whether you are getting your protein from meat, fish, eggs, or dairy, any protein derived from an animal product increases the body’s production of insulin-like growth factor 1 (IGF-1), a growth-promoting hormone that accelerates the aging process and contributes to the growth, proliferation, and spread of cancer cells. Animal protein intake and insulin-like growth factor (IGF-1) levels have been linked in numerous studies to a greater risk of being diagnosed with or dying from cancer.

2- No beans: By eliminating all foods that were unavailable before the dawn of agriculture, Paleo dieters cut beans and other legumes (like lentils and split peas) out completely. Consumption of beans and other legumes is a common dietary practice among older people across many countries who live the longest. Beans are especially rich in resistant starch and fiber, which fuel to growth of a healthy gut microbiome and help to prevent colon cancer. Beans are nutritionally valuable, a low glycemic load food that helps to reduce cholesterol and blood pressure.

3- Exposure to carcinogens and pro-inflammatory compounds: Eating a small amount of meat, eggs, or dairy, about two servings per week, is unlikely to harm your health. However, eating animal products every day is risky. In addition to animal protein, meats contain carcinogens, such as nitrosamines (mostly in processed meats) and heterocyclic amines (formed in all meats, including poultry and fish during cooking). Heme iron from meat is an oxidant that accumulates in the body over time, and excess contributes to heart disease and dementia. Carnitine, choline, and arachidonic acid are pro-inflammatory, contributing to cardiovascular disease and cancer. Growth-promoting hormones given to farmed animals are present in animal foods, potentially leading to endocrine disrupting effects in those who eat these products. It is also worth noting that persistent organic pollutants, like DDT, PCBs, and dioxin, are resistant to breaking down and accumulate in the fatty tissue of animals. Animal foods are our major source of exposure to these pollutants.

Based on this information, it is clear that forming your meals around animal products and eliminating other, more healthful options—beans, nuts, fruits, and vegetables—is a road to ruin. A Paleo diet reduces anti-oxidant exposure and increases exposure to inflammation-promoting compounds. Although these types of diets can be successful for weight loss in the short term, because they eliminate refined grains and sugars along with processed foods, over the long term they are neither sustainable nor healthful.

The Long-Term Healthy Diet

The only successful, long-term solution to achieving substantial and permanent weight loss is through a diet that gets most of its calories from natural plant sources and only a small amount from animal products. Whole plant foods do not raise IGF-1, do not promote inflammation, and are rich in life-extending phytochemicals that fuel the body’s repair mechanisms.

To get healthy, be healthy, and to remain healthy your diet has to be comprised primarily of vegetables, fruits, beans, nuts and seeds. Limit the amount of meat, fish, eggs and dairy foods to under 10 percent of your total caloric intake, and preferably under 5 percent, and steer clear of sugars and processed foods. Place an emphasis on eating a variety of the most health-promoting foods, based on their nutrient density and anti-cancer potential.

The healthiest way to eat uses liberal amounts of raw and cooked leafy greens, cruciferous and colorful vegetables, and an abundance of beans, a variety of fruits, some intact whole grains, as well as raw nuts and seeds. It is called a Nutritarian diet. A Nutritarian diet takes the weight off while also warding off type 2 diabetes, heart disease, osteoporosis, cancer, stroke, dementia, arthritis, migraines and acne.