Final answer:
Trans triglycerides, or trans fats, are solid at room temperature due to their ability to pack tightly together. They are commonly found in processed foods but are being reduced due to health risks. Saturated fats, also solid at room temperature, usually come from animal sources.
Step-by-step explanation:
Foods rich in trans triglycerides, often referred to as trans fats, are typically solid at room temperature. Triglycerides with trans double bonds have linear fatty acid chains which can pack tightly together, leading them to be solid. In contrast, unsaturated triglycerides that have cis double bonds tend to be liquid at room temperature because the cis configuration introduces a bend in the chain, preventing the molecules from packing closely. Common sources of trans fats include various types of processed and fried foods, baked goods, and some margarines.
It's important to note that trans fats have been linked to an increased risk of cardiovascular disease. As such, they are being reduced or eliminated in many foods by manufacturers. On the other hand, saturated fats, which are also solid at room temperature, typically come from animal sources and contain only single bonds within the carbon chain.