Butter, oils, animal fats-all of these are sources of triglycerides, a type of fat found in your blood. Eating too many of these foods can lead to high triglycerides, but it's not the only cause. "Our bodies also convert excess calories into triglycerides, which then get stored in our fat cells for future energy needs," says Elizabeth Harris, M.S., RDN, LDN. Why does all of this matter? High triglycerides can increase your risk for more serious heart-health issues.