They were hunter-gatherers and we're mouse-clickers. Can returning to the eating style of the Paleolithic era really be the best thing for a modern-day diet?
The Paleo Diet: Is Eating Like Our (Very Distant) Ancestors Really a Good Idea?

Whether you've tried it yourself or know someone who has, chances are you've at least heard about the paleo diet. This diet has been around since the 1960s, but in the last five years it has seen a surge in devoted fans, as evidenced by the many blogs, Instagrams and specialized cookbooks dedicated to eating like a Paleolithic human. Eating like our ancestors likely requires a dramatic shift in your overall food strategy because of all the food groups the diet excludes. If you're considering trying the paleo diet or just want to adopt elements of it into your eating habits, keep reading. We help define the paleo diet and break down the pros and cons.

What Is the Paleo Diet?

The paleo diet aims to mimic the eating habits of our Paleolithic-period ancestors. They lived between 2.5 million and 10,000 years ago. The diet emphasizes eating more fruits and vegetables, as well as free-range, grass-fed meats, wild-caught fish and nuts.

Dairy, grains, legumes, sugar (with the exception of honey) and most vegetable oils are all excluded, as are processed foods. The idea, in theory, is that by imitating our ancestors' diets, we can go back to a simpler, preindustrial time, avoid the foods that have allegedly led to modern diseases, like obesity and diabetes, and eat more whole, unprocessed foods.

Sounds great, right? Unfortunately, it's not quite as simple as that. Before jumping on board, there are a few things to consider.

A Lot Has Changed Since the "Original" Paleo Diet

Roast Chicken & Sweet Potatoes

On a broad level, it's important to remember that it's impossible to accurately imitate the diet and lifestyle of our Paleolithic ancestors. We can base a diet loosely off what we know, but some experts are concerned that some paleo dieters have "misguided perceptions of health and weight benefits" of this diet. Lori Lieberman, R.D., M.P.H., a private-practice dietitian who specializes in eating disorders in Sharon, Massachusetts, points out that those ancestors often didn't survive past their 30s and weren't always healthy, noting evidence of early heart disease.

Though we have a rough idea of what they ate, it's difficult to pinpoint ratios of meat to produce, as our ancestors constantly had to be flexible and adjust their diets based on geography, season and opportunity. There were many different tribes whose diets varied greatly from one to another, so defining the paleo diet in the one way we do today is a bit of an oversimplification.

Additionally, it's important to remember that a piece of fruit now is not the same as a piece of fruit thousands or millions of years ago, and the same goes for meat. Not only have plant and animal species changed over time, but unless you're a farmer or hunter, your method of obtaining these foods is likely quite different-and less strenuous-than that of our hunter-gatherer ancestors. You're not burning calories the same way you would if you were hunting and gathering when you go out for your next meal-unless you jog or bike to the supermarket.

Pro: You'll Eat Fewer Processed Foods

Garlic Shrimp with Cilantro Spaghetti Squash

The most positive aspect of the diet is arguably the exclusion of packaged, boxed and processed foods. They are often filled with unnecessary sodium, sugar and preservatives. Additionally, the focus on fruits and vegetables is a plus, as the USDA encourages every adult to eat 5 to 9 servings a day (and most of us don't get enough). Fruits and vegetables are packed with fiber, antioxidants and vitamins and minerals. One caveat: The diet can be relatively low-carbohydrate, and carbohydrates are an important source of fuel for our bodies. It's important to make sure you're getting enough carbs if you do decide to try the paleo diet. Paleo dieters are allowed healthy carbohydrates from vegetables like sweet potatoes and squash, but healthy sources of carbs like whole grains and legumes are eliminated.

Pro: You May Seek Out More Sustainably Raised Meat

One of the key features of "eating paleo" is increased protein intake. While the diet's focus on game meat is relatively positive-game tends to be a leaner choice-it's not always easy to find and thus may be limiting for some. The diet also emphasizes purchasing animal protein that has been raised sustainably-our ancestors weren't eating factory-raised meats. It's better for the environment and possibly for your health to eat sustainable proteins. Grass-fed beef and wild-caught fish are typically richer in omega-3s.

Con: Protein Takes Center Stage (and That's Not Always Good)

You have to be diligent about making sure you're getting a balanced diet. For example, people who take a more general approach to the diet can easily end up eating a lot of meat without necessarily focusing on the type. This could lead to a high saturated fat intake-a typical paleo diet plan does exceed the USDA Dietary Guidelines for daily fat and protein intake, as noted on the Academy of Nutrition and Dietetics website.

Con: Some Banned Foods Are Quite Healthy

Like many diets, the paleo diet has a long list of foods not to eat. This list includes dairy and grains-whole and refined. Both of these are recommended as part of the USDA's MyPlate and are important food groups, even if our ancestors did not have access to them.

Low-fat or nonfat dairy is an important source of calcium and vitamin D and has been shown to benefit bone health, improve blood pressure and reduce risk of heart disease and diabetes. Grains, particularly whole grains, are full of B vitamins, folate, fiber and other nutrients. Whole grains have been shown to reduce the risk of stroke, heart disease and diabetes. According to a U.S. News and World report of 38 diets, the paleo diet is "one of the few diets that experts actually considered somewhat unsafe and only somewhat complete nutritionally," because of the exclusion of entire food groups.

Con: Eating Paleo Leaves a Big Footprint

Because this diet promotes a relatively high meat intake, one more factor to consider is the environmental impact of meat production. According to the Environmental Working Group, between 1971 and 2010 the worldwide production of meat tripled to around 600 billion pounds, while the global population grew by just 81 percent in comparison. EWG estimates that "at this rate, production will double by 2050 to approximately 1.2 trillion pounds of meat per year, requiring more water, land, fuel, pesticides and fertilizer and causing significant damage to the planet and global health." Over time, if more people were to follow this diet and consume even more meat, the environment could suffer severe consequences.

To feel better about your meat footprint, opt for meat and eggs that are certified organic, humane and/or grass-fed, as these are generally the least environmentally damaging and most ethical choices.

Bottom Line on the Paleo Diet

While there is no research on the long-term health effects of the paleo diet-the few studies that have been conducted have been short-term, with small participation numbers, and did not examine disease risk over time or mortality rates-long-term studies on meat consumption show higher mortality rates among those consuming diets high in animal proteins.

If you want to lose weight or follow a healthier diet in general, take the positives from the paleo diet-avoiding processed foods and filling your plate with fruits and vegetables-and modify it. Include dairy and whole grains, and limit meat consumption.

When you can, pick local, organic produce and meats. They're best for you and the environment. Unlike our ancestors, we are lucky to have more options, resources and knowledge available to us than our Paleolithic ancestors did; as a result, we don't have to follow as limited a diet.

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