Recent research has cast doubt on the trendy Paleo diet, an eating plan that encourages consumption of meat and discourages consumption of grains and other processed foods.

The Paleo diet has become popular in part because it makes some intuitive sense. Humans were hunter-gatherers long before the advent of farming, so it is not unreasonable to speculate that our bodies might be well-suited to subsist on the meats, vegetables and nuts that our Paleolithic hunter-gatherer ancestors ate for all of those millennia.

Proponents of the Paleo diet argue that modern humans are prone to packing on excess pounds in part because we now eat processed foods and farm products such as grains that our early ancestors did not eat.

But while the Paleo diet is a compelling theory, there has never been much research to back it up. And now a study has cast doubt on whether the Paleo diet even was healthy for people who lived during Paleolithic times. When researchers at St. Luke’s Mid America Heart Institute in Kansas City conducted CT scans on 137 ancient mummies from four different parts of the globe, they discovered that more than one-third of them showed signs of heart disease (though it is worth noting that Paleolithic people probably smoked most or all of their meat over fires, a preparation technique that likely exacerbates heart disease dangers).

Meanwhile, a long-term study conducted in China by researchers from Cornell, Oxford and the Chinese Academy of Preventive Medicine found a strong correlation between the consumption of meat (as well as dairy products) and coronary heart disease, casting further doubt on the healthfulness of meat-heavy diets.

Advice: Exercise caution in trying the Paleo diet (or any other meat-heavy diet) if you have a history of heart disease and/or if heart problems run in your family. But this diet might be a reasonable option if your doctor confirms that your heart is in good shape and if you choose grains high in soluble fiber, such as oats or flax, which have been shown to help lower blood pressure and stroke risk.