Study Ranks Paleo As Second-Worst Diet

Learn why 'U.S. News & World Report' expert panelists are not in favor of the Paleo diet.

Much like the CrossFit craze that's produced many of its adherents, the Paleo diet has grown exponentially more popular in recent years. But a new survey of effective eating plans questions whether that growth is a good thing.

Paleo, which is based on the idea that modern humans should eat like their ancestors did thousands of years ago in Paleolithic times, before adopting mass agriculture techniques. The diet emphasizes protein intake from meat, seafood and eggs, and forbids processed foods, grains, legumes, peanuts and refined sugar. 

U.S. News & World Report asked a panel of 22 nutrition and health experts to scrutinize 35 popular diets and rank them according to several criteria, including their effect on heart health, usefulness for long-term weight loss and likelihood that someone can actually stick to the diet for good.

Their results, which were released in U.S. News & World Report's Best Diets for 2015, ranked Paleo near the bottom, 34th out of 35,  in terms of its effectiveness.

"My main concern with Paleo is that it emphasizes this all-or-nothing mentality that is hard to sustain," said panelist Elisabetta Politi, the Nutrition Director at the Duke Diet and Fitness Center in North Carolina. "To say that we shouldn't eat brown rice or shouldn't have sweet potatoes, for instance, especially when it comes to athletes who need carbohydrates for energy, might not be the best way to get to your peak athletic performance."

"Any diet that limits an entire food group is a huge red flag," said another panelist, Kathie Beals, Ph.D., Associate Professor and dietician at the University of Utah.

According to the panelists' writeup, Paleo suffers from two main pitfalls. First, following the diet can be very expensive, since it relies heavily on items like meat and fish—two of the priciest items in the grocery store. Second, the plan is challenging to follow since it eschews all processed foods, even ones that many experts consider healthy.

"It's kind of unrealistic to think that we're not going to rely on any food that is provided by the food industry in today's society," Politi said. "We don't live in a rural, prehistoric society and can't just pretend that we do."

Panelists also found that the Paleo diet falls short in providing adequate intake of carbohydrates (23% of daily calories from carbohydrates vs. government recommended 45-65%) and that it over delivers on the amount of fat (39% vs. 35%). Another concern is that a person following a Paleo diet would miss out on key nutrients from whole grains as well as dairy, and that the high consumption of non-lean meat items could lead to cholesterol and heart problems.

Although the U.S. News & World Report article also concluded that insufficient evidence exists showing that Paleo supports cardiovascular health, weight loss or diabetes prevention, Loren Cordain, Ph.D., a leading advocate for the Paleo diet, co-wrote a rebuttal to the diet list, citing several studies she says support Paleo's potential to improve those areas of one's health.

RELATED: Is The Paleo Diet Right For Athletes?

In then number 1 spot for the fifth year in a row for best overall diet was DASH, which stands for Dietary Approaches to Stop Hypertension. Originally implemented to reduce high blood pressure, DASH emphasizes foods high in fiber, calcium, potassium and magnesium—which is basically a version of the Mediterranean diet of whole grains, fruit, vegetables, low-fat dairy, nuts, beans and fish (or other lean protein). DASH limits the amount of sugar, saturated fat, salt and red meat you should eat. Check out the video player above for more tips on how to build a healthy plate.

Ultimately, how beneficial a diet will be for a person varies based on their specific needs and situation. With its restriction on carb intake, Paleo is a poor option for endurance athletes, panelists felt, but the diet may be a suitable choice for strength-based athletes.

"For a person who might do an hour of CrossFit, and the majority of what they're doing is strength work where they're not using that much glucose during their workout, [Paleo] probably is not going to be detrimental to their health," Beals said.


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