Is the Keto Diet Safe for Your Heart?

For years now, the ketogenic diet has grabbed attention for how swiftly its followers slim down. Now it's getting scientific bona fides for helping people who have type 2 diabetes control their blood sugar—and potentially protect their hearts, since over time, high blood sugar can damage blood vessels and increase one's risk of cardiovascular disease. But if you know anything about keto, you know that this diet has also caused some raised eyebrows. To sort through the speculation, we turned to the literature. As for what science says, once and for all? We tapped a cardiologist to weigh in—but, as it turns out, opinions are split, he says.

In Favor of Keto

Keto, which is all about fats, calls for drastically cutting carbs—which turns out to be a particularly effective way for anyone who is overweight or obese to shed pounds and lower their risk.

Against Keto

The studies so far are short-term, yet the diet may well do harm in the long run, since the extra saturated fats consumed (in red meat, say) are linked to heart disease. "People are mesmerized by the weight loss and diabetes control, but if they end up dying from heart attacks or cancer down the line, then what?" says the American College of Cardiology's Andrew Freeman, M.D., co-author of a recent study in the American Journal of Medicine on the impact of keto and intermittent fasting diets on heart health.

The Verdict

Neither Dr. Freeman's study nor his organization fully endorses keto yet. But some cardiologists do support its use in certain cases, so talk to your doctor about the diet that is best for you.