This investigative case module was prepared as part of a BioQUEST faculty development workshop entitled NSF Chautauqua Short Course: Investigative Cases at Christian Brothers University in July 2004. The cases, resources, and implementation strategies were developed by participants for use with their own students. We invite you to adopt and adapt the following materials.

The BioQUEST Curriculum Consortium is committed to the reform of undergraduate biology instruction through an emphasis on engaging students in realistic scientific practices. This approach is sometimes characterized as an inquiry driven approach and is captured in BioQUEST's three P's (problem-posing, problem-solving, and peer-persuasion). As part of this workshop groups of faculty were encouraged to initiate innovative curricular projects. We are sharing these works in progress in the hope that they will stimulate further exploration, collaboration and development. Please see the following links for additional information:

Upcoming events                Investigative Cases

Investigative Cases
The Case: Fad Diets and Metabolic Regulation

Flipping through his local restaurant menu, John notices the new "low carb" addition. "What's with this?" he asks his wife.

She explains, "It has to do with the Atkins diet fad. I expect these menu inserts will disappear as quickly as they have appeared. A calorie is a calorie, so why should it make any difference whether they're from a steak or a pastry? I think these fad diets work only because people on them are constantly obsessing about what they're eating."

The waitress, who is diabetic, overheard this conversation as she bussed a nearby table. She turns to the couple and offers, "Low carb diets work by altering our appetite...something about insulin or other hormones."

Case Author:
Richard Nelson Wabash College

Case Analysis

How do hormones regulate physiologal processes?
How do hormone work mechanistically?
What homeostatic mechanisms are there that regulate body weight?
Are there differences in hormonal responses to different types of foods?
What does it mean to be diabetic?
Is there a scientific basis for recent diet fads?

Option: Include a know / need to know chart like the one below:

What do you know?
What do you need to know?

Learning Goals


*Understanding the interplay between homeostatic mechanisms

*Hormonal regulation *Mechanisms of hormonal action, signaling

*Connecting broad physiological processes with molecular events

*Genetic control of phenotype



Investigations and Activities

*Group investigations of important questions derived from case description *Computer simulation of dietary intake, blood glucose, insulin, glucagon, leptin hormone levels

*Comparison of leptin/leptin receptor allelic sequences from normal and obese individuals



*Web-based resources

*Textbooks on human physiology

*Software application to simulate blood glucose, hormone responses to food intake

Students will usually obtain additional references or resources
to help answer or explore their questions.

Special Data Items
(Montague et al.) Congenital leptin deficiency is associated with severe early onset obesity in humans. Nature 387, 903-908)
(Strobel, A, Camoin, T.I.L., Ozata, M., and Strosberg, A.D.) A leptin missense mutation is associated with hypogonadism and morbid obesity. Nature Genet. 18-213-215 (1997)) Physiol Genomics. 2004 Apr 13;17(2):101-6. Epub 2004 Feb 17.

1. mutants.jpg
2. lm.jpg
3. hrs.jpg


Student Products

*Group report (written and/or oral) on investigation of a particular aspect of the case study
*Report on hypothesis testing, data analysis using simulation software
*Worksheet on leptin alleles that correlate with obesity

Assessment and Evaluation Plan

*Peer assessment of participation in case study investigation
*Graded report on simulation data Graded worksheet on gene sequence analysis



Case Study Narrative, identification of questions, and web exploration on Friday. Related activities for 1 hour of lab the following week. Reports on the following Friday during class time.

Course name:
Human Biology (Bio101), a non-majors course
Likely sequence in syllabus:
Time during term:
About the 4th week of the semester
2 lecture periods, 1 hour of a laboratory period
Students in course:
Collaborative elements:
Collaborative exploration of questions revealed in discussion of case narrative
Additional notes:



ICBL Home              Back to list of investigative cases

Copyright 2009, Investigative Cased Based Learning Project