Which type of dietary fat is considered harmful in excessive amounts?

Trans fats are considered harmful in excessive amounts primarily because they not only increase low-density lipoprotein (LDL) cholesterol, often referred to as "bad" cholesterol, but they also lower high-density lipoprotein (HDL) cholesterol, known as "good" cholesterol. This dual effect significantly raises the risk of cardiovascular disease and other health problems. The consumption of trans fats has been linked to inflammation, insulin resistance, and various health issues, which is why health organizations recommend minimizing or eliminating them from the diet.

While unsaturated fats are generally viewed as beneficial for heart health and can improve cholesterol levels when used in place of saturated and trans fats, excessive intake of any type of fat can lead to weight gain and associated health risks. Saturated fats, while also needing moderation, are not as universally condemned as trans fats for their harmful effects on health. Therefore, the consensus is that trans fats are most clearly identified as harmful, especially when consumed in large quantities.