Your body needs cholesterol to make essential hormones, cell membranes and brain and nerve tissues, but your liver manufactures all the cholesterol your body needs. The cholesterol from your diet is all excess.

Your body turns cholesterol into good high-density lipoproteins (HDLs) and bad low-density lipoproteins (LDLs). HDLs get rid of excess cholesterol, and LDLs promote fatty buildup in your arteries. Having high levels of LDLs can clog blood vessels and lead to heart disease, America’s number one killer.

Your cholesterol profile results partly from heredity and age, but your diet and level of physical activity also contribute.

What should your numbers be? Ideally, your total cholesterol level should be lower than 200 mg/dL. HDL (the good cholesterol) should be 60 mg/dL or higher. LDL (the bad cholesterol) should be below 100 mg/dL. Triglycerides should be below 150 mg/dL.

What if you find out your cholesterol levels are high? While some people need medicine, experts still regard a healthy lifestyle as the first line of defense against cholesterol problems. Proper diet, regular exercise and avoiding smoking can all help keep cholesterol in check.