1 The three energy-yielding food nutrients are carbohydrates, proteins, and fats. The amount of energy a food provides depends o

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问题 1 The three energy-yielding food nutrients are carbohydrates, proteins, and fats. The amount of energy a food provides depends on how much of each nutrient it contains. When broken down in the body, a gram of carbohydrate and a gram of protein each yield about four kilocalories of energy. A gram of fat yields nine kilocalories; therefore, fat has a greater energy density than either protein or carbohydrates. Foods with a high energy density provide more kilocalories per gram than foods with a low energy density.
2 Different meals may deliver the same number of kilocalories but varying amounts of food energy. For example, a 450-gram breakfast of cereal, milk, fruit, egg, turkey sausage, toast, and jam and a 150-gram breakfast of doughnuts both deliver 500 kilocalories. However, the first breakfast, which is higher in protein, has a lower energy density than the doughnuts and supplies three times as much food energy.
3 During a meal, as food enters the digestive tract, hunger decreases and the body reaches satiation, the signal to stop eating. The nutrient composition of a meal affects the level of satiation the meal provides. Foods low in energy density are more satiating than foods high in energy density. Of the three energy-yielding nutrients, protein is the most satiating and fat is the least satiating. High-fat foods are flavorful, which encourages people to eat more, but they are also energy-dense and deliver more kilocalories per bite. Therefore, eating meals high in fat may lead to overconsumption.
Which sentence below best expresses the essential information in the highlighted sentence in paragraph 2?

选项 A、Although the first breakfast is higher in protein, the doughnuts are higher in food energy.
B、The high-protein, less energy-dense breakfast provides three times as much energy as the doughnuts.
C、The doughnuts provide more food energy than the first breakfast, which is lower in energy density.
D、Because the doughnuts are higher in fat, they contain three times as much food energy as the other breakfast.

答案B

解析 The high-protein, less energy-dense breakfast... is a paraphrase of However, the first breakfast, which is higher in protein, has a lower energy density than the doughnuts.......provides three times as much energy as the doughnuts is a paraphrase of ...and supplies three times as much food energy.
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