It is well known that cutting out refined foods, sugar, and added salt can benefit your health. But the benefits of the other aspects of the Paleo Diet, in particular the large percentage of animal products consumed, are less cut-and-dry. And they have the potential to impact much more than your health. Here are four things to consider before going Paleo:

1. Despite the hype, there's no evidence that the Paleo Diet lowers mortality or the risk of heart disease and cancer.
2. A 2012 Harvard study followed thousands of health professionals and nurses for 20 to 26 years and found a 12 percent higher death rate among those eating a low-carb diet that was also high in animal protein, such as beef and dairy. Those eating large percentages of animal protein were 14 percent more likely to die of heart disease and 28 percent more likely to die of cancer.
3. Greenhouse gas (GHG) production is considerably higher for most animal products than plant-based foods. Not only is raising (e.g., feeding) animals very resource intensive, but some livestock also release methane -- a potent GHG.
4. Unless you're eating a varied, seasonal diet including tubers, sedges, fruits, animals, insects, worms, leaves, and bark, you're not eating Paleo, say anthropologists Ken Sayers and C. Owen Lovejoy.

If really you want to eat like early humans, keep your diet local, plant-heavy, seasonal, and go for variety. More…

If the people who lived before agriculture were healthier than us, they rarely lived long enough to reap these benefits, says Kenneth Sayers, an anthropologist at the Language Research Center of Georgia State University. It was unusual for hunter-gatherers to live much beyond reproductive age, he says, and "it's hard to be healthy when you're dead."

The paleo diet is built on nostalgia and erroneous notions of how evolution works, says Marlene Zuk, an evolutionary biologist at the University of Minnesota in St. Paul and author of "Paleofantasy: What Evolution Really Tells Us About Sex, Diet, and How We Live."

Another problem with the paleo diet is that it makes unscientific assumptions about what our ancestors ate, Lieberman says. "There was no one single paleo diet; there were many," he says. Our Stone Age relatives lived in a diverse range of habitats, from tropical regions of Africa to rain forests, boreal forests and tundra regions, he says, and their diets varied according to what was available in these habitats. "There is no one time and place and habitat to which we're adapted," Lieberman says. More…

I do not find it "natural" at all. Instead, I think it's an invitation to serious disease and environmental destruction! Here's some of what I find problematic with the Paleo approach to eating:

Did our cave-man ancestors really eat a mostly-meat diet? Although it's a commonly held idea with a colorful image, it's just not true. According to Nathaniel Dominy, associate professor of Anthropology at Dartmouth College, the overwhelming majority of calories that kept our ancestors alive in ancient times were from starches, in the form of roots, tubers, bulbs, corms and wild grasses ? mostly gathered by the women of the tribes (bless ?em!).

All plants make and store starches and there is a reason that over the millions of years before humans appeared, our primate ancestors developed starch-digesting enzymes (amylases) in our saliva that begins digesting starches down to usable sugars right in our mouths. Our grinding teeth (not flesh-tearing fangs) and long digestive system are very efficient for processing starchy plant foods; our pancreas pours amylase-rich juice into the gut with every meal and amylases cascade off the walls of the small intestine into the food stream throughout its 22 foot length.

Carbohydrates (sugars) are clean burning fuels, leaving only carbon dioxide and water as wastes, easily excreted by the lungs and kidneys. But flesh is a "dirty" fuel, leaving urea, ketones, uric acid and other metabolic burdens that can stress the liver and build up to disease-producing levels, resulting in gout, kidney stones, and other diseases.

Burning fat-heavy fuels places one in a state of ketosis, something sought after by Paleo promoters as a "good thing." However, keeping one's metabolism in a state of ketosis ? an emergency state the body enters during times of starvation ? is NOT a good thing! It is a state of low-grade acidosis and being ketotic day after day, week after week, that forces the body to constantly dispose of an acid load which can leach calcium from the bones and precipitate kidney stones.

Despite what the Paleo promoters push, we are not carnivorous apes. The Paleo diet would have us ghoulishly swallow chunks of flesh every five hours as part of our meat-based, "natural" diet. My goodness! Not even mountain lions eat flesh every 5 hours! No other primate eats flesh like this and the health consequences can be severe. More…

Essentially all of the great apes and their ancestors appeared to have eaten a C3-based diet, consuming fruits, leaves and other plants. Modern humans, on the other hand, rely much more on C4 plants, which include grains like wheat and corn. What researchers didn?t know was when that shift occurred. The PNAS papers show that this shift appears to have occurred in Australopithecus afarensis, which lived in and around Ethiopia 2.9 to 3.9 million years ago.

This shift coincided with the retreat of heavily forested areas that were replaced by open savannah.

Big brains and upright walking are two of the main factors that distinguish humans from other primates, and it appears that a shift in diet from leaves to grasses may be a significant third factor.

So while there remains little doubt that many modern humans eat too much sugar and processed foods, these studies show that identifying a particular ?paleo? diet is impossible. Researchers are just beginning to understand what ancient humans ate, and these recent studies show that grasses and grains have been part of the human diet for millions of years. More…

Starch and carbohydrates in the tartar show the Neanderthals ate a variety of plants, but there were surprisingly few traces of meat-associated proteins or lipids.

Not only did our extinct cousins prefer grilling vegetables to steaks, they were also dosing themselves with medicinal plants,

Since the techniques were already well established during the Mid-Upper Paleolithic Period, it's likely that modern humans, and possibly even Neanderthals, incorporated far more plant products into their diets than presently believed.

Right now, one half of all Americans are on a diet. The other half just gave up on their diets and are on a binge. Collectively, we are overweight, sick and struggling. Our modern choices about what and how much to eat have gone terribly wrong. The time has come to return to a more sensible way of eating and living, but which way? An entire class of self-help books recommends a return to the diets of our ancestors. Paleolithic diets, caveman diets, primal diets and the like, urge us to eat like the ancients. Taken too literally, such diets are ridiculous. After all, sometimes our ancestors starved to death and the starving to death diet, well, it ends badly. The past was no panacea; each generation we made due with the bodies and foods available, imperfect bodies and imperfect foods. Yet, the idea that we might take our ancestral diet into consideration when evaluating the foods on which our organs, cells and existence thrive, makes sense. But what did our ancestors eat?

We evolved eating huge amounts of plants. It's estimated that 200,000 years ago we got 600mg of vitamin C a day. That's the amount of vitamin C found in 10 oranges. Every day we appear to have consumed the amount of vitamin E found in 2 cups of nuts, the amount of fiber found in 12 bowls of oatmeal, and the amount of calcium found in 5 cups of collard greens. They weren't milking mammoths—that came in part from all the wild greens they foraged. More…

No matter what you call the fad of eating more meat and less grains, beans, and other agricultural products—Paleo, caveman, Stone Age, hunter-gatherer—this diet is not going to support overall, long-term health.

On the upside, "Paleo" diets do discourage processed food products and dairy products. But a couple of steps in the right direction cannot overcome the giant pitfalls that result from eating high-fat, high-cholesterol meat products and avoiding nutrient-dense plant foods like beans and whole grains. More…

A vegan weight-loss surgeon says a plant-based diet is the healthiest eating plan to enhance longevity and stave off obesity, diabetes and heart disease.

Dr. Garth Davis, who has performed gastric-bypass and lap-band surgeries on morbidly obese people for 12 years, says trendy high-protein diets such as the Paleo and Atkins diets are warped and misguided.

"In 12 years of doing weight-loss surgery, I have never operated on a vegetarian," Davis said Sept. 19 on a podcast with vegan ultra-marathoner/triathlete Rich Roll. "No one's getting fat on broccoli. No one comes in and says, 'I'm eating too many grapes.' " More…

Among my own people, the Choctaw Indians of Mississippi and Oklahoma, vegetables are the traditional diet mainstay. A French manuscript of the eighteenth century describes the Choctaws' vegetarian leanings in shelter and food. The homes were constructed not of skins, but of wood, mud, bark and cane. The principal food, eaten daily from earthen pots, was a vegetarian stew containing corn, pumpkin and beans. The bread was made from corn and acorns. Other common favorites were roasted corn and corn porridge. (Meat in the form of small game was an infrequent repast.) The ancient Choctaws were, first and foremost, farmers. Even the clothing was plant based, artistically embroidered dresses for the women and cotton breeches for the men. Choctaws have never adorned their hair with feathers.