Lecture 14: Diet Problem/Intro
to Final Project
AGEC 352
Spring 2011 – March 21
R. Keeney
Final Project

Tomorrow
◦ Start back in on transportation problems
◦ Lab with discussion questions etc.

Today
◦ Discuss final projects for AGEC 352
Diet Problems

Of longstanding interest:
◦ Impoverished nations and the poverty
problem
 What does it cost to provide enough food?
◦ Food inflation and costs
 How has the minimum cost diet changed over time?
◦ Food costs, low income, and health
 Are problems like obesity more prevalent in low
income households due to types of foods that are
most affordable?
Linear Programming
Most common tool used in analysis of
diet costs
 Blending problem

◦ What combination of foods satisfies a set of
daily requirements at lowest cost?
 (See fertilizer mix or cereal problems)

Key issue:
◦ What values and nutritional factors to use in
the constraints?
Subsistence Problem

In the 1940s, Stigler was worried about
world hunger and conducted a study of
the cost of subsistence
◦ Subsistence = staying alive

Collected information from health
research and food products to estimate
the cheapest way to eat enough to
survive
Stigler

You are required to read the paper
◦ Link provided on class website

Read closely enough to answer the
following questions:
◦ What does he state as his purpose for study?
◦ What are his primary findings?
◦ What comparisons does he make between
foods and years on diet cost?
◦ What method did he use?
Final Project

Assignment #1
◦ Part of the project grade requires you to
collect data and submit
 Details in Part I of the handout provided
◦ Submit a spreadsheet with information on
cost and nutrition data for 15 different foods
◦ Each student required to submit data
 If you work together, find 30 foods and split them
up. Do not submit the same lists.
 No beverages, no more than 5 restaurant foods
FP Assignment #1

Cost on a per serving basis
◦ E.g. Can of Pringles cost $1.50
◦ Six servings -> $0.25 per serving
Nutrition facts on the package should be
reported per serving
 Report on 15 items and submit the
spreadsheet to aremble@purdue.edu

◦ Deadline is Friday at noon
FP Assignment #1
Information required
 Specific format must be followed

Table 1. Data and Units required for each food
Data Item
Price
Calories
Total Fat
Sodium
Carbohydrates
Dietary Fiber
Protein
Vitamin A
Vitamin C
Calcium
Iron
Units/serving
Dollars
Cal
Grams
Milligrams
Grams
Grams
Grams
%2K
%2K
%2K
%2K



Price on a serving basis
No formulas in the spreadsheet you
submit
Make sure you report the units and not
the percentages for the first six items
◦ Both will be shown

Report the percentage for the last four
items as a whole number
Example Nutrition Facts
Report as the
quantity/weight amount.
Report as percentages: Use
the whole number not the
proportion or %.
Spreadsheet format

Use the example McDonald’s spreadsheet
as a template. Just delete the McD foods
and type in your information
◦ Remember: no formulas
Save the spreadsheet as
fooddata_yourinitials.xlsx or .xls
 Email to aremble@purdue.edu

◦ Put Food Data 352 in the email subject line
Final Project
Amber will compile the data submitted by
students and post to the course website
for everyone’s use
 Use this database to build an LP diet
model for your final project
 Two Parts

◦ 1) Subsistence model: Lowest cost diet that
meets minimum requirements
◦ 2) Your choice: propose a question and change
the model to deal with that question
Part I: Subsistence Model
Nutritional Item
Calories
Fat*
Sodium
Carbohydrates
Fiber
Protein
Vitamin A**
Vitamin C**
Calcium**
Iron**
Minimum Amount
2500
0
1500 mg
130 g
38 g
56 g
125 %
125 %
125 %
125 %
Example RHS values for a
subsistence model.
Assumptions:
1) 30 years old
2) Male
3) Mildly active
See the DRI tables for
other assumptions.
Note the last 4 items are
just scaled to the size of
the diet.
125=(2500/2000)*100
Part II

Requirements
◦ LP model used to address your question

Simple questions
◦ Vegetarian vs. mixed food model
◦ Upper bounds as well as lower bounds on
nutritional items
 e.g. 2500 < = Calories < = 2750

Other questions
◦ Cost of food pyramid guidelines (integer
constraints)
◦ Cost of being diabetic or bulking up (constraint
information)
Other requirements/information
You must use at least 20 foods and no
more than 40 foods
 The paper must not exceed 6 pages of
text

◦
◦
◦
◦
10 point font min.
1 inch margin min. (all sides)
No title page (just use the upper left corner)
All tables at end of document (solution and
sensitivity)
Other information

Submit a hard copy to me
◦ Thursday of Dead week = Bonus (5%)
◦ Wednesday of Finals week
 Late penalty = -25% of project grade

20 percent of your final grade and
replaces final exam
Grading criteria

Part I
◦ Common question -> comparative grading
 Best answers will receive the highest scores.
 Effectiveness at interpreting results and sensitivity and
communicating those in words will be the primary basis of the
score.

Part II
◦ Different questions -> grade based on execution
 How well does your approach match the question you
pose and do you make the reasoning clear?
 Also the solution interpretation and communciation of findings
(answer to your question).
Lab Tomorrow

Continue working with the Eurotrans
model
◦ If you haven’t completed the handout from
last week, try and get caught up before lab
starts tomorrow because we will continue
from the last part of that assignment
Answers to HW 5 questions are due on
Wednesday.
 Quiz on Wednesday over the
Transportation Model handout.
