Shirin wants to replace eating junk food with the alternative behavior of eating fruit. Shirin makes sure that she always has fruit in her house, so that when she wants something to eat, it is easy for her to choose a healthy option. Which of the following statements best describes Shirin's approach to changing her eating habits?
1) Shirin is trying to reduce her overall calorie intake.
2) Shirin is trying to increase her consumption of vitamins and minerals.
3) Shirin is trying to eliminate all unhealthy foods from her diet.
4) Shirin is trying to establish a new habit of eating fruit instead of junk food.