Passage 2:  As humans, we develop habits that we follow throughout life. These habits save us time and mental energy, allowing us to perform many actions without using concentrated thought. While many of the typical person’s habits are healthy, most of us also develop a number of unhealthy habits over time. In order to change them, you need to identify the behavior, the cause of the behavior, and the emotion that follows the behavior. One of the most important healthy habits is to follow a proper diet each day. Eat a medium-sized breakfast, followed by a light lunch and dinner. Snack on whole grains, fat-free dairy products, nuts, seeds and fresh fruits and vegetables. Drink plenty of water and avoid sodas and foods high in cholesterol, saturated fats and sugars. Avoid eating large portions, and eat only when you are hungry, never because you are bored, emotionally depressed or stressed. A regular, nutritious diet is important to your physical health. Many doctors recommend maintaining the same sleep schedule seven days a week in order to keep the body accustomed to a routine. Sleep in a dark room without distractions such as music or other noise. If you regularly have difficulty falling or staying asleep, ask your physician about other ways to relax before bedtime. The human body also requires regular exercise for health, but many people fail to adopt good exercise habits. Regular exercise can help prevent chronic diseases, such as heart failure. When life gets too busy and fast, many fail to develop healthy stress management habits. Talking and laughing with friends, watching a movie, taking a nature walk, reading a book or playing a game can all help decrease stress levels.  What is the main idea of the passage 2?