Copyright Goodheart-Willcox Co., Inc. Chapter 3 Nutrition 73 No single plant source contains all of the essential amino ac- ids. You must eat multiple types of protein-rich plants to obtain all of the amino acids. For this reason, vegetarians must ensure they are including complementary proteins in their diet. Comple- mentary proteins are two or more incomplete protein sources that together provide adequate amounts of all the essential amino acids. For example, rice contains low amounts of certain essential amino acids however, these same essential amino acids are found in greater amounts in dry beans. Similarly, dry beans contain lower amounts of other essential amino acids that are found in larger amounts in rice. Together, rice and beans provide adequate amounts of all the essential amino acids (Figure 3.4). In the past, it was thought that complementary proteins needed to be eaten at the same meal for the body to use them together. Now studies show that the body can combine com- plementary proteins that are eaten at different times during the day, as long as they are eaten within the same day. Fats Fats F are a type of nutrient that is largely made up of fatty acids, which provide a valuable source of energy. Fatty acids are a particularly impor- tant source of energy for muscles. Common fats in the diet include satu- rated fats, unsaturated fats, trans fats, and cholesterol. Saturated Fats fats Saturated f are found primarily in animal-based foods, such as meat and dairy products. These are called saturated fats because the carbon at- oms in these fats have all the hydrogen atoms they can hold. Saturated fats are typically solid at room temperature. Unsaturated Fats fats Unsaturated f are found in plant-based foods such as vegetable oils, some peanut butters and margarines, olives, salad dressing, nuts, and seeds (Figure 3.5 on the next page). As you might guess, unsaturated fats do not have all the hydrogen atoms they could hold. They have at least one double bond to which an additional hydrogen atom can be added. Unsatu- rated fats are liquid at room temperature. Trans Fats fats Trans f are created by a process known as hydrogenation, which bom- bards an unsaturated fat with hydrogen atoms and changes double bonds to single bonds. This makes the fat more saturated and, therefore, more solid. This Eating enough of the right complementary proteins can provide your body with all nine essential amino acids in a day. What are some meals you eat that might combine complementary proteins? Figure 3.4 fatt f a a type of nutrient, composed of fatty acids, that is a valuable source of energy, especially for muscles saturated fat t a type of fat found primarily in animal-based foods that is solid at room temperature unsaturated fat t a type of fat that is liquid at room temperature and is found in plant-based foods trans fat t a type of fat that is created by hydrogenation poses health risks acknowledged by the FDA