There are really only a few basic habits we know should help keep people healthy: eating well, exercising, avoiding smoking, and keeping body fat in check.

Turns out a shockingly tiny number — just 2.7 percent — of Americans actually manage all four habits, according to a new study published in Mayo Clinic Proceedings.

The research, led by Paul Loprinzi of the University of Mississippi, used data about the lifestyles of nearly 5,000 US adults from the 2003 to 2006 National Health and Nutrition Examination Survey. (That’s the Centers for Disease Control and Prevention’s biggest national health survey.)

The researchers zeroed in on information about exercise (whether people got 150 minutes of moderate to vigorous physical activity weekly based on accelerometer data) and smoking status (measured by blood levels of cotinine, a biomarker for tobacco exposure). As for eating habits, the researchers looked at self-reported 24-hour recall data about diet and used the Healthy Eating Index score (an indicator of diet quality that takes into account how many fruits and vegetables people eat, as well as meat, […]