Final answer:
Partially hydrogenated oils indicate the presence of trans fats in food. Margarine, certain types of peanut butter, and shortening are examples of foods that may contain trans fats. The FDA requires food labels to disclose trans fat content.
Step-by-step explanation:
Trans fats are indicated on an ingredient legend by the presence of partially hydrogenated oils. When a food label lists partially hydrogenated oil as an ingredient, it means that the product contains trans fats. This is because partially hydrogenated oils are created by chemically converting liquid oils into solid fats, resulting in the formation of trans fatty acids.
Margarine, certain types of peanut butter, and shortening are examples of foods that may contain trans fats. These artificially hydrogenated trans fats have been linked to an increased risk of heart disease due to their ability to raise levels of low-density lipoproteins (LDL), or 'bad' cholesterol, in the bloodstream.
It is important to note that the FDA has taken steps to eliminate trans fats from the food supply, and food labels are now required to disclose the trans fat content. This allows consumers to make informed choices and monitor their intake of trans fats, which should be kept as low as possible in accordance with dietary guidelines.