In February of last year, the International Journal of General Medicine published a study that was easy to miss, as no major media publication reported on "Total Meat Intake is Associated with Life Expectancy: A Cross-Sectional Data Analysis of 175 Contemporary Populations," by Wenpeng You and his team of researchers.

For years we have heard that the secret to a long life is to cut back on meat consumption and increase our intake of carbs—advice that is enshrined in the USDA's Dietary Guidelines for Americans. But that's not what these researchers found.

You and his team analyzed data from 175 countries and territories—in other words, almost the whole world—and used various statistical methods to "explore and compare the correlations between newborn life expectancy … life expectancy at five years of life … and intakes of meat, and carbohydrate crops, respectively. The established risk factors to life expectancy—caloric intake, urbanization, obesity and education levels—were included as the potential confounders."

The researchers found that worldwide, meat intake was associated with a longer life. "This relationship remained significant when influences of caloric intake, urbanization, obesity, education and carbohydrate crops were statistically controlled." By contrast, consumption of carbohydrates had a weak but negative correlation with life expectancy.

Blue Zones and Meat Consumption

You may be wondering about the "blue zone" areas of the world—those with a high percentage of centenarians. According to Dan Buettner, author of "The Blue Zones, Lessons for Living Longer From the People Who've Lived the Longest," the key to a long life is to minimize meat consumption and eat plenty of vegetables.

Don't the long-lived people living in the blue zones eat a mostly plant-based diet?

Well, actually, no. For example, in Sardinia, Mr. Buettner's first noted blue zone, meat consumption is higher among the long-lived peasants living in the mountains than those living in the valleys, according to a 2015 study published in the European Journal of Clinical Nutrition. Say the authors:

"The identification of a hot spot of exceptional longevity, the Longevity Blue Zone (LBZ), in the mountain population of Sardinia has aroused considerable interest toward its traditional food as one of the potential causal factors … Up to a short time ago, the LBZ population depended mostly upon livestock rearing, and consumption of animal-derived foods was relatively higher than in the rest of the island." [emphasis added]