The modern Paleo Diet is based on the simple idea that the diet humans ate in pre-agricultural, Paleolithic times is best suited for human health. Whether what these short-lived humans ate is truly the optimal diet for people today is a matter of considerable debate.
At first glance, the assumption that our nutritional requirements were established in the prehistoric past seems reasonable. But the question is, which period should we base our diets on?
What was the real Paleolithic diet?
A key shortcoming of the Paleo diet rationale is that it ignores the first 90% of our evolution. Why consider just the last 2 million years of our existence when mankind evolved for 25 million years?
Pre-agricultural diets consisted of wild plants, wild animals and wild fish, but the volume varied widely, depending on location, season, and hunting and gathering skills. People didn’t eat oil, sugar, salt, processed foods or the milk of other mammals. This is the diet today’s Paleo Diet fans try to mimic.
Nutritional anthropologists believe vegan diets may more closely match the macro- and micronutrient intake of Paleolithic diets than new paleo diets. Analysis of human paleo feces and undigested plant remains strongly suggests that for most of our existence, people ate a fiber-filled, plant-based diet. Our hunter-gatherer days occurred only toward the end of our evolution.
Food Quality, Then and Now
There’s a big difference between the food consumed today and that eaten in the Paleolithic era. The wild animals eaten then provided about 6 to 16 percent of calories from fat compared to about 40 to 60 percent in today’s domestic animals—even those that are grass-fed. Prehistoric meat was also free of hormones, antibiotics and environmental contaminants. Insects were a significant protein source.
Hybrid strains of fruits and vegetables are chosen today based on how easily they’re transported and a blemish-free appearance rather than nutritional value. Wild or uncultivated plants, it should be noted, provide about four times the fiber of commercially grown plants.
Today’s Paleo Diet eschews grains and legumes, despite these foods having a long history as a valuable protein and calorie source around the world, including those regions where the people are among the longest and healthiest on the planet.
Health Outcomes on Paleo Diet
The Paleo Diet may harm heart health by impairing arterial function. Studies have shown that diets typified by high protein and fat but low carbohydrates were associated with poorer peripheral small artery function.
At the same time, the Paleo Diet’s emphasis on consuming bone broth ignores the heavy lead contamination of meat and fish from fish by-products fed to farmed animals and fish. Even broth made from organic chicken bones was found to contain markedly high lead concentrations. Lead has adverse effects on nearly every organ in the body and tends to stay in the body for as much as 30 years.
The Paleo Diet’s emphasis on consuming large quantities of meat ignores numerous health risks associated with eating meat and fish, along with the many ethical issues associated with industrial farm practices and its long-term unsustainability.
Image credit: Arleevector / Thinkstock. This image has been modified.
Topic summary contributed by Dawn Handschuh
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