单选题 .  As we know, if we want to keep our healthy and have a strong body, our eating habits are very important in our daily life. There are times when most of us would rather eat sweets and ice cream than meat and rice. Actually, sweets and ice cream are not bad for the stomach if we eat them at the end of a meal. If we eat them before a meal, they may take away our appetite. Meanwhile, it is important for us to eat our meal at the same time each day. When we feel hungry, it shows that our bodies need food. When we feel angry or excited, we may not want to eat. When we are worried, we may not want to eat, either. A long time ago, in England, some judges used to decide whether a man was telling the truth by giving him some dry bread. If the man could not swallow the bread, it was a sign that he wasn't telling the truth. Although this seems very strange and rather foolish, it is indeed an excellent way of finding out the truth. A man who is worrying about something has difficulty in swallowing anything dry. He loses his appetite and does not want to eat anything if he is worrying something.1.  We have to develop good eating habits because ______.