Discuss with students the problems with rising obesity rates
in America. Draw from current events as appropriate to help illustrate the
point. Some suggested resources are listed under Related Resources, although
other, timelier, resources might be available for your classroom.
Discuss with students the causes for obesity. Keep in mind
(and point out to them) that there are many causes for obesity, some of which
may or may not be within a person's control, such as genetics and medical
conditions. Keep an eye out for comments from students that might imply obesity
is entirely an obese person's fault and address them if they come up. Have them
list causes that they can think of. Steer them towards considering rising
portion sizes as one cause. Explain that while there are many components of a
healthy diet, just like there are many causes for rising obesity levels, today
in class you will examine one: portion size. Remind students that this is an oversimplification
of a complex issue (refer to the list to imply just how complicated it is) but
it is one important element.
Increasing Portions, Expanding Waist Lines Article Activity Sheet
Increasing Portions, Expanding Waist Lines Activity Sheet
Increasing Portions, Expanding Waist Lines Answer Key
Have students read the Increasing
Portions, Expanding Waist Lines Article independently. Then, hold a brief class
discussion on what they read and learned.
Distribute the Increasing Portions, Expanding Waist Lines
Activity Sheet. Have students work through it, perhaps in pairs or groups of
three. If you don't want to stop and discuss the activity periodically with the
class, you should circulate and discuss different elements with groups, or
combine the two. You want to help push and refine student thinking, so even
students that have correct answers can be pushed to deepen their thinking.
In Question 4, there is intentionally a mismatch between
units. Students wrote their function in terms of weeks in Question 3 and they
have to answer Question 4 in terms of months and years. Help them work flexibly
through the many ways they can convert units to make it work.
In Question 5, caution students to use an appropriate viewing window when graphing the function.
Help them figure out what a reasonable viewing window would be for each
The calorie information in this activity was obtained from
the calorie calculator at MayoClinic.com. Adjust the information so that it is
slightly different for each group, or have students make their own hypothetical
person, if you prefer.
After groups have had a significant amount of time to work
(let them be at least halfway done) distribute overheads or poster paper for
them to record their work and share with the class, either via presentations or
a gallery walk. (During a gallery walk, groups walk around and observe each
other's work. This may be a good opportunity for students to assess each
As a closing activity, have students write or journal about
their own eating habits. Remind students that unhealthy weights can be too low
as well as too high. Give students a safe place to reflect on their
relationship with food. Be aware that you might have some students for whom
this can be a delicate issue. Keep an eye out for anyone who might be bothered
by this activity. If you are uncomfortable or feel you don't know your students
well enough to support them through a potentially sensitive journal exercise,
consider something more objective, like having students analyze the calories in
different school lunch choices or a restaurant menu and write about what
healthier choices are (or are not) available. Another alternative is to have students create a one day healthy menu for breakfast, lunch, and dinner that provides 2160 calories.