Math-in-CTE Lesson Plan Template
Lesson Title: Body Mass Index (BMI)
Author(s):Carol
Jarosinski
Huggler
&
Lucille
Lesson # 18
Phone Number(s):
908-309-9480—Carol
1853-Lucille
E-mail Address(es): hugrn01@yahoo.com
732-232- surfmagee@verizon.net
Occupational Area: Health Occupations
CTE Concept(s): Calculating Body Mass Index (BMI)
Math Concepts: multiplication, division, exponents
Lesson Objective:
To calculate BMI
Supplies Needed:
Pencils, paper, calculators, scale
TEACHER NOTES
(and answer key)
1. Introduce the CTE lesson.
Students had previous lessons on the gastrointestinal system, the endocrine system, cultural
Today, we are going to continue our assessment of our health. diversity, nutrition, eating disorders, vital signs, and measuring ht. & wt. They are able to
Remember, in our last lesson we measured our height and weight convert between pounds and kg and inches and cm. Review 1 Kg = 2.2 lbs. and 1 inch =
and converted them to cm and kg?
2.54 cm and put ex. Of each on board and ask students to calculate:
THE "7 ELEMENTS"
Ask: how many pounds are in one kilogram (Kg)? How many cm
12 inches = 30.48 cm
are in one inch?
50 pounds= 22.73 kg
Now we are going to use these measurements to calculate our Body Body Mass Index (BMI) is a number calculated from a person's weight & height. BMI is used
Mass Index (BMI).
to determine if you are overweight. The BMI equation (BMI = Body Mass Index) was originally
framed by Adolphe Quetelet, a Belgium mathematician & scientist, between 1830 and 1850.
Ask: Does anyone know what BMI is?
Adolphe was the first person to think of relating wt. to ht. in a statistical, expressible manner.
In the 1950's and 1960's we were getting noticeably fatter, so Adolphe's nineteenth century
BMI equation was dusted off and used to express relative thinness or fatness across a large
population. Whether working with average weight, over-weight, or underweight people the
BMI calculation provides a snapshot of relative weight. Calculating BMI is one of the best
methods for population assessment of overweight and obesity. Because calculation requires
only ht & wt, it is inexpensive and easy to use for clinicians & for the general public. The use
of BMI allows people to compare their own wt. status to that of the general population.
Ask: Define overweight and obese.
Overweight is defined as having more body fat than is optimally healthy (BMI 25-29.9).
Obese is defined as a condition in which excess body fat has accumulated to the extent that it
may have an adverse effect on health leading to reduced life expectancy and health problems
(BMI of ≥ 30).
Interpretation of BMI for adults
For adults 20 years old and older, BMI is interpreted using standard weight status categories
that are the same for all ages and for both men and women. For children and teens, on the
other hand, the interpretation of BMI is both age- and sex-specific.
The standard wt. status categories associated with BMI ranges for adults are shown in the
following table.
BMI
Weight Status
Below 18.5
Underweight
18.5 – 24.9
Normal
25.0 – 29.9
Overweight
30.0 and Above
Obese
Ask: Why is BMI calculated differently for children and teens?
Although the BMI number is calculated the same way for children and adults, the criteria used
to interpret the meaning of the BMI number for children and teens are different from those
used for adults. For children and teens, BMI age- and sex-specific percentiles are used for
two reasons:

The amount of body fat changes with age.

The amount of body fat differs between girls and boys.
The CDC BMI-for-age growth charts take into account these differences and allow translation
of a BMI number into a percentile for a child's sex and age. How is BMI calculated and
interpreted for children and teens?
Ask: How is BMI calculated and interpreted for children
and teens?
Calculating and interpreting BMI using the BMI Percentile Calculator involves the following
steps:
1. Before calculating BMI, obtain accurate height and weight measurements.
2. Calculate the BMI and percentile using the Child and Teen BMI Calculator.
http://apps.nccd.cdc.gov/dnpabmi/
The BMI number is calculated using standard formulas.
3. Review the calculated BMI-for-age percentile and results. The BMI-for-age percentile is
used to interpret the BMI number because BMI is both age-and sex-specific for children and
teens.
4. Find the weight status category for the calculated BMI-for-age percentile as shown in the
following table. These categories are based on expert committee recommendations.
Ask: What shortcomings or problems might happen when using
BMI?
Percentile Range
Underweight
Less than the 5th percentile
Healthy weight
5th percentile to less than the
85th percentile
Overweight
85th to less than the 95th
percentile
Obese
Equal to or greater than the 95th
percentile
For adults, on the other hand, BMI is interpreted through categories that do not take into
account sex or age.
The correlation between the BMI number and body fatness is fairly strong; however the
correlation varies by sex, race, and age. These variations include the following examples:

Ask: How else can we evaluate a healthy size?
Weight Status
Category
At the same BMI, women tend to have more body fat than men.

At the same BMI, older people, on average, tend to have more body fat than younger
adults.

Highly trained athletes may have a high BMI because of increased muscularity rather
than increased body fatness.
In consideration of these shortcomings of the BMI, two other factors are evaluated.
----Waist circumference – excess fat in abdomen is greater health risk than excess fat in the
hips and thighs. It crowds the abdominal organs and its proximity to liver means that when
metabolized, abdominal fat can raise blood cholesterol levels and lower the body’s sensitivity
to insulin.
--Greater than 35 inches for female and 40 inches for males.
Ask: What diseases or disorders may occur if you are overweight or ----Presence of weight-related health problems and risk factors for diseases. These include
obese?
family health history, heart disease, type 2 diabetes mellitus, high blood cholesterol, high
blood pressure, stroke, cigarette smoking, osteoarthritis, gallstones, or sleep apnea.
2. Assess students’ math awareness as it relates to the CTE Review :
lesson.
1 foot = 12 inches, 1 yard = 3 feet, 1 Kg = 2.2 lbs., 1 inch = 2.54 cm, 1 meter = 100 cm
Put ex. Of each on board and ask students to calculate:
60 inches = 165.1 cm
120 pounds = 54.5 kg
172 cm =1.72 meters
3. Work through the math example embedded in the CTE Suppose you weigh 160 pounds and are 5 feet 10 inches tall. Here's how you calculate your
BMI:
lesson.
1. Convert you height into inches: (5 feet x 12 inches) + 10 inches = 70 inches
Metric units
meters squared
or wt in kg / ht in
2. Now (the hard part!) square your height in inches: 70 x 70 = 4900
3. Divide weight by the squared height: 160 / 4900 = .0326
USA
or wt in lbs
/ by ht in inches squared multiplied by 703
4. Multiply by the correcting factor of 703 since you're not using metric: .0326 x 703 = 22.9
BMI
Hand out attached worksheet—converting pounds-Kg, Kg- pounds, inches to cm, cm-inches,
and cm to meters. Students to work individually and then review together in class.
4. Work through related, contextual math-in-CTE examples.
See attached worksheet. Students to work on them individually and then ask for volunteers to
put on board. Discuss categories that the pts. Are in.
5. Work through traditional math examples.
See attached worksheet—working thru multiplication, division, exponents. Students to work
on them individually and then ask for volunteers to put on board.
6. Students demonstrate their understanding.
See attached sheet with case studies. Split class into groups to:
Split class into groups for a case study analysis. After 15 minutes,
have each group present their pt. to rest of class with their findings
and suggestions.
1.
Calculate the BMI for the pt.
2. Determine which category they fall into (underweight, normal, overweight, or
obese)
3. Discuss possible reasons for this pt. to fall into that category (include culture,
family and social history, medical and surgical histories, and any medications
they take).
4. Plan what you as the nurse or health care professional would counsel the pt. to
do (diet, exercise, etc.)
The discussion of the findings could include asking questions prompting my students to gear
their brains thinking healthy thoughts. Such as: Why do think obesity is on the rise? Why do
people have different body shapes?
7. Formal assessment.
A take home worksheet that shows the student’s own calculated BMI and category
using the formula and the child and teen calculator.
http://apps.nccd.cdc.gov/dnpabmi
The worksheet must also include an essay determining why you think you have a
particular BMI index. What factors might be involved in your own BMI? Include
genetics, culture, diet, and exercise regimes.
NOTES:
Be sure to be sensitive to students who may not want to share their weight and BMI/category. Ask for volunteers to share their own BMI only if they
want!
Helpful websites:
•CDC - Division of Nutrition and Physical Activity
www.cdc.gov/nccdphp/dnpa/bmi/index.htm
•Body and Mind - BAM
www.bam.gov
•Healthfinder.gov
www.healthfinder.gov/http://mobile.nourishinteractive.com/hco/lesson_plans/kids_nutrition_bmi_lesson_plans_teaching_children_healthy_body_mass_index
http://www.nhlbi.nih.gov/guidelines/obesity/bmi_tbl.pdf
http://www.nhlbisupport.com/bmi/