Biology

NATIONAL CENTER FOR CASE STUDY TEACHING IN SCIENCE

The Hunger Pains: Ghrelin, Weight Loss, and Maintenance by Lynn M. Diener Sciences Department Mount Mary College, Milwaukee, WI

Part I – You Look Fantastic! Mallory Messner Hey Sara, it was great to see you during break! It’s been way too long. And by the way, congratulations on the weight loss, you look fantastic. Do you mind if I ask how you did it? April 5 at 1:32pm Like

Sara Finnegan Mal, it was great to see you too! Tanks for noticing the weight loss, it required a lot of hard work. I started exercising 5 days a week and restricting calories (eating smaller portions mainly). April 5 at 1:45pm Like

Mallory Messner You’d think I would already have realized that there is no trick when it comes to weight loss, being a biology major and all–sigh–I just hoped maybe you had found some magic solution. Haha. April 5 at 1:50pm Like

Sara Finnegan I gotta tell you though, I’m having a heck of a time keeping the weight of. It seems like I’m always hungry! You know, they always say that only 5% of people who lose weight ever keep it of long term. I’m hoping to remain in the 5% but right now I’m not so sure. =(

Have you heard about some hormone called ghrelin in any of your biology classes? I’ve been reading about it in the news lately, I wonder if it has anything to do with my struggles… April 5 at 1:55pm Like

Mallory Messner Actually I do recall learning something about ghrelin in class. Let me take a look and get back to you. I’ll send you an email! April 5 at 1:57pm Like

Questions 1. Craft an email from Mallory to Sara explaining some of the basics of ghrelin. Your email should explain what a

hormone is and what kind of hormone ghrelin is. It should also explore ghrelin’s efect on growth hormone and metabolism. Feel free to use your textbook and reliable internet sources.

2. What is the efect of growth hormone on metabolism? Pay special attention to its efect on protein, bone, fatty tissue, and carbohydrates.

3. What does anabolic mean? What about catabolic? How would you classify growth hormone?

“Te Hunger Pains” by Lynn M. Diener Page 1

NATIONAL CENTER FOR CASE STUDY TEACHING IN SCIENCE

Part II – Sleep Is Important Mallory Messner So ghrelin seems like an intriguing possibility, huh? Did you know that it’s generally elevated in people after they lose weight? Even a whole year after they lost the weight! April 5 at 6:03pm Like

Sara Finnegan Yeah, thanks for the email. I can’t believe that a chemical like ghrelin can help to increase your appetite. And the fact that it’s elevated in people after they lose weight, ugh! April 5 at 6:09pm Like

Mallory Messner I found some other really interesting studies about ghrelin. How are you sleeping lately? April 5 at 6:12pm Like

Sara Finnegan I’m a college sophomore, just like you, how do you think I’m sleeping? April 5 at 6:14pm Like

Mallory Messner Haha, point taken. Well one study found some correlations with sleep and ghrelin levels. More sleep, less ghrelin! I found their data on the correlation between hours of sleep and BMI interesting as well.

Hours of sleep Average BMI Standard error 6.10 32.15 0.70 6.55 31.4 0.25 7.40 31.05 0.25 8.25 31.4 0.30 9.10 31.6 0.50

April 5 at 6:23pm Like

Questions 1. Make a line graph of this data using the space below. Don’t forget to include error bars using the standard error.

Identify and label the dependent and independent variables; this will dictate their placement on your graph.

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NATIONAL CENTER FOR CASE STUDY TEACHING IN SCIENCE

2. Explain the trend you see in the data you graphed.

3. Using a ruler, show which error bars overlap and don’t overlap on the graph above.

4. Without knowing the results of any statistics done on the data, which data point(s) may be signifcantly diferent from each other based on the data provided? Which data did you rely on to come to your conclusion?

5. Knowing that less sleep means more ghrelin, what suggestions might you make to Sara if you were Mallory? What is a take-away message for this study?

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NATIONAL CENTER FOR CASE STUDY TEACHING IN SCIENCE

Part III – Dessert for Breakfast Sara Finnegan Maybe I need to start prioritizing my sleep just a little bit… April 5 at 7:01pm Like

Mallory Messner Seriously! Me too… =) Another really fascinating recent study looked at the timing and composition of calories ingested, focusing specifcally on breakfast. Are you familiar with those high protein diets? April 5 at 7:04pm Like

Sara Finnegan Oh yeah, my roommate is trying to lose weight that way. April 5 at 7:06pm Like

Mallory Messner Well researchers had one group of obese individuals eat a small (calorie-wise), protein enriched breakfast in the morning. Te other group ate many more calories high in carbohydrates and enriched in protein. Both ingested the same number of calories over the course of the whole day, the diferences were in the timing and quantity of fats, carbs and protein. Te amusing part is that the second group of dieters also had dessert with every breakfast. =D April 5 at 7:10pm Like

Sara Finnegan Seriously??? I’d love to start every morning with dessert. I bet I know who lost weight and who didn’t. April 5 at 7:13pm Like

Mallory Messner Seriously! And we’re talking doughnuts, cake, chocolate bars. You might fnd the results surprising though. Here, take a look at the weight loss data. Tey were “dieting” from weeks 0 till 16. Week 16–32 was follow up, when they were trying to maintain their weight loss.

Low calorie breakfast Dessert for breakfast Time (weeks) average weight (kg) average weight (kg)

0 89 91 4 85 87 8 82 85 12 77 82 16 75 78 20 78 76 24 81 74 28 84 72 32 87 71

April 5 at 7:21pm Like

Questions 1. Make a line graph of the data above in the space provided below.

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NATIONAL CENTER FOR CASE STUDY TEACHING IN SCIENCE

2. What is the trend the researchers saw? You should focus on which group lost more weight and had more successful weight loss maintenance.

3. Do you think Sara is surprised by the results?

4. Does ghrelin make you hungry or leave you feeling satisfed?

5. Knowing what you do about ghrelin, in which case do you think the researchers saw a greater decrease in ghrelin after eating?

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NATIONAL CENTER FOR CASE STUDY TEACHING IN SCIENCE

Part IV – Easier Weight Loss? Sara Finnegan Mal, that’s a seriously cool study. 30 minutes ago Like

Mallory Messner I know! And they saw all sorts of other things change in the dessert group. Levels of ghrelin decreased after meals, feelings of satiety (satisfaction) increased, and cravings decreased. 28 minutes ago Like

Sara Finnegan Haha, maybe I’ll try the dessert for breakfast diet to combat my difculty in maintaining. 25 minutes ago Like

Mallory Messner Well, it’s only one study. I’m not sure I’d change your whole diet outlook based on one study, but the results are defnitely compelling. Tere really is a lot left to learn about ghrelin and weight loss in general. 20 minutes ago Like

Questions 1. Speculate about why the dessert for breakfast group saw decreases in cravings and increases in satiety.

2. Would you change your diet based on the study? What kind of evidence is necessary to make you “believe” a research study?

3. If you were doing research in this area, what would be your next step?

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Credit: Licensed image in title block © Konstantin Andy #1627988 | Fotolia. Case copyright held by the National Center for Case Study Teaching in Science, University at Bufalo, State University of New York. Originally published September 17, 2012. Please see our usage guidelines, which outline our policy concerning permissible reproduction of this work.

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