Be creative with your presentation.  Some suggestions include:

• Wear workout gear to the presentation.
• Toss a ball or beanbag around the classroom to encourage dialogue.
• Bring in props such as hula-hoops, jump ropes, etc.
• Make trail mix with the students.
• Illustrate how many teaspoons of sugar are in one can of soda.
• Invite a local sports figure to participate in the presentation.
• Analyze a fast food meal.
• Allow students to select a healthy meal from their school lunch offerings and attempt to estimate calories, fats, and carbohydrates.
• Bring a number of food items to class and let the students arrange them in nutritional (caloric) order.
• Compare nutritional values of popular snacks. 

Create a competition with the pedometers to see which classmates take the most steps in a week.