[originaltext]　　(16)Choosing what to eat seems like a simple decision, but vari

　　(16)Choosing what to eat seems like a simple decision, but various factors have a role. Your environment, mood and amount of time you have all make a difference. These factors are directly affected by the American lifestyle and culture. The fast-paced, busy lives of Americans affect their food decisions in various ways. Americans should blame a "terrible food environment" for the over-weight epidemic. (17) Scientists pointed to the wide availability of high-fat and high-sugar foods, large serving sizes, advertisements for processed foods and lack of physical activity as reasons for Americans’ weight gain. It is said that policy, not self-control, should be emphasized if Americans want to lose weight. Americans’ fast-paced lifestyle may be a part to blame for their expanding waistline. Most "convenience foods," such as pre-packaged snacks or fast food, are nutritionally lacking and filled with too much fat and sugar. These foods lead to increased blood pressure because they are high in salt. Those watching their blood pressure should read food labels and watch for packages labeled low sugar. If you’re watching your health, look for high-fiber foods labeled low fat. To eat these foods and still watch your weight, (18)clinics recommend reading food labels, watching total calorie intake and eating foods high in fiber. The high stress level in many Americans’ lives leaves them turning
　　to rich, comfort foods. (19)Long-term stress leads to love for high-fat, high-sugar foods. When under high levels of stress, there are other ways to deal with it, including exercise, yoga, etc.
　　16.  What directly affects the food decisions of Americans?
　　17.  What may cause Americans’ over-weight epidemic according to scientists?
　　18.  What do clinics suggest people do to keep healthy?
　　19.  How has stress affected Americans?