This one’s a little tricky. Although it’s long been thought that having high HDL is protective, a new study in The Lancet suggests that’s not necessarily the case across the board. The study followed people who had genetic markers for high HDL (and had higher HDL cholesterol), but had other similar risk factors for a heart attack as people without the gene. Although it was thought that having higher HDL would confer a 13% lower risk against a heart attack, researchers found that the higher HDL group didn’t have lower rates of heart disease than people not genetically predisposed to high HDL. That doesn’t mean high HDL isn’t still a good thing—it’s just that why your HDL is high probably makes a difference. Healthy habits, such as exercise and eating enough fiber and healthy monounsaturated fats, happen to raise your HDL and lower your risk of heart disease.