What are trans fats, and why are they considered unhealthy?

Trans fats are a specific type of unsaturated fat that undergoes a process known as hydrogenation, where hydrogen is added to liquid vegetable oils to make them more solid. This processing creates trans fats, which can be found in many processed foods, including some margarine, baked goods, and fried foods.

The reason trans fats are considered unhealthy primarily revolves around their effect on heart health. They have been shown to not only raise levels of low-density lipoprotein (LDL), often referred to as "bad cholesterol," but also to lower high-density lipoprotein (HDL) or "good cholesterol." This imbalance increases the risk of developing heart disease, stroke, and type 2 diabetes.

Natural unsaturated fats, on the other hand, such as those found in fish or avocados, do not share the same harmful effects as trans fats and can be beneficial when included in moderation as part of a balanced diet. Hence, the key distinction lies in the artificial processing of trans fats, which contributes significantly to their negative health impacts.