Any diet on which you eat fewer calories than you need to get through the day — like an 800-calorie-per-day diet can be dangerous. Diets that don't allow any fat also can be bad for you. Everyone needs a certain amount of fat in their diet — up to 30% of total calories — so no one should eat a completely fat-free diet.
Don't have diets that restrict （限制）certain food groups, either. A diet that requires you to say no to bread or pasta or allows you to eat only fruit is unhealthy. You won't get the vitamins and minerals you need. And although you may lose weight, you'll probably gain it back as soon as you start eating normally again.
Some people start dieting because they think all the problems in their lives are because of weight. Others have an area of their lives that they can't control, like an alcoholic parent, so they focus on something they can control — their exercise and food intake.
People who diet may get lots of praise from friends and family when they start losing pounds, which makes them feel good. But eventually a person reaches a weight level — and doesn't lose as much weight as before because the body is trying to keep a healthy weight, so they aren't any happier.
Some people may find it hard to control their eating, so they stick with an extreme diet for a little while, but then eat tons of food. Feeling guilty about the binge, they use laxatives（泻药）. Eating too little to maintain a healthy weight or eating only to throw up the calories are both eating disorders, which are harmful to a person's health.
1. Which is not the result of restricting certain food groups?
A. lose weight for a short period         B. unhealthy  
C. short of nutrition                     D. hungry
2. The reasons why some people start and keep dieting DON’T include__________.
A. They think their trouble comes from their weight.
B. They have an alcoholic parent.
C. Other people’s praise when they lose some weight.
D. There is something they can’t control except food intake.
3. The underlined phrase in the last paragraph refers to _________.
A. a fat-free diet               B. a special diet   
C. eating too much            D. eating too little
4. Which of the following statements is true?
A. A person needs about 800 calories each day.
B. A person who doesn’t eat bread is unhealthy.
C. An improper diet may cause eating disorder.
D. Fat takes up the most part of calories inside body.
5. According to the passage, when people want to lose weight, they should_________.
A. avoid eating some food that can lead to being fat   B. control their eating amount and times
C. have a healthy and balanced diet                D. throw up some of what they eat