The term "unhealthy fats" refers to types of dietary fat that can have negative effects on health when consumed in excess. These fats are typically high in saturated or trans-fat content, and may contribute to increased cholesterol levels, heart disease, and other health problems. Examples of unhealthy fats include butter, lard, and many processed foods containing hydrogenated oils. In contrast, "healthy fats" are those that provide essential nutrients and may have positive effects on overall health when consumed in moderation, such as avocados, nuts, seeds, and certain types of fish oil.