A
While some extreme diets may suggest otherwise, we all need a balance of protein, fat, carbohydrates, fiber, vitamins, and minerals in our diets to keep a healthy body. You don't need to remove certain kinds of foods from your diet, but rather select the healthiest ones.
Protein
Protein gives us the energy to get up and go—and keep going while also supporting mood and cognitive function （认知功能）. Too much protein can be harmful to people with kidney disease, but the latest research suggests that many of us need more high-quality protein, especially as we age. That doesn't mean you have to eat more animal products—a variety of plant-based sources of protein each day can ensure your body gets all the necessary protein it needs.
Fat
Not all fat is the same. While bad fat can destroy your diet and increase the possibility of certain diseases, good fat protects your brain and heart. In fact, healthy fat—such as omega-3s—is necessary to your physical and emotional health. Understanding how to include more healthy fat in your diet can help improve your mood and your well-beings.
Fiber
Eating foods high in dietary fiber（grain, fruit, vegetables, nuts, and beans）can help you stay regular and lower the possibility of heart disease, strokes, and diabetes. It can also improve your skin and even help you to lose weight; Depending on your age and gender, experts suggest you eat at least 21 to 38 grams of fiber each day.
Calcium（钙）
Your body uses calcium to build healthy bones and teeth, keep them strong, send messages through the nervous system, and control the heart's rhythm. Not getting enough calcium in your diet can also lead to anxiety, depression, and sleep difficulties. Whatever your age or gender, it's necessary to include calcium-rich foods in your diet.
21. What can we know about protein from the second paragraph?
A. Protein can improve a person's mood.
B. We should have less protein when we get older.
C. The animal products provide more protein.
D. We should have as much protein as possible.
22. Which is one benefit of foods in high fiber?
A. They provide more energy. B. They are good for eyesight.
C. They help build healthy teeth. D. They help improve the skin.
23. What's the effect of shortage of calcium?
A. People may become older easily.
B. People may have trouble with sleep.
C. People may have the risk of kidney disease.
D. People may gain weight quickly in a short time.
