Aim: Why is obesity considered an eating disorder? Do Now: List three causes of obesity. HW: due tomorrow read actively and take notes in the margin on “Information Integration” section of the article Test Next Friday 11/21 on Nutrition, Food Pyramid, Food Labeling, Eating Disorders (Aneorxia, Bulimia, Obesity) and presentations on Digestive Disorders. Projects due 11/17. Presentations will begin that day. ALL MUST BE READY TO GO!

What is Obesity?  When a person is carrying too much body fat for their height and sex  A person is considered obese if they have a Body Mass Index (BMI) > 30  Obesity has now become one of the most serious medical problems of the western world  Childhood obesity is also on the rise

Causes of Obesity High fat, high caloric food Decrease in physical activity Increase in fast food consumption More TV watching, computer and video games Super-sized portions Increase soft drink consumption Less activity in daily life Genetic factors

An important balance… ENERGY BALANCE To maintain weight, intake of calories must equal calories used in activity ENERGY INTAKE = ENERGY OUTPUT Energy Intake--calories supplied from foods eaten Energy Output--calories used during physical activity/exercise ENERGY IMBALANCE WEIGHT GAIN ENERGY INTAKE > ENERGY OUTPUT WEIGHT LOSS ENERGY INTAKE < ENERGY OUTPUT

Activity…  Actively read the Introduction and section entitled “Fat-o-Stat.  Circle any words you are unfamiliar with  Take notes in the margin and underline important points (15 minutes)  Share your notes and ideas with a partner

Aim: What are the genetic causes of obesity?  Do Now: Begin/finish activity on article “What Fuels Fat.”  Hand in project #2  Test Friday on Nutrition, Food Pyramid, Food Labeling, Eating Disorders (Aneorxia, Bulimia, Obesity) and presentations on Digestive Disorders.

Activity...  Work in pairs to answer the discussion questions on the handout given in class  Be complete in your answers. The test on Friday will cover these questions!

Questions….  How has evolution played a role in fostering an increase in obesity in recent years? In the past we needed energy storage to get us through times when food was scarce. Through technological advances we now have an abundance of food and less physical activity.  What is the function of adipose tissue? To take in extra glucose and store it as triglycerides  What are keytones? Acids that are released during the breakdown of triglycerides  What is the goal of human’s regulation mechanism on fat? To preserve fat in light of evolution

Questions continued…  What gene is linked to obesity? FTO gene. Not much information is known about the function of this gene. But it is associated with an increase in body weight.  What are some environmental factors that can affect fat regulation? Decrease in physical activity, increase in food supply, effect of nutrition during fetal development, stress, sleep deprivation, and viral infections (adenovirus)

Questions…  Which region of the brain is associated with energy regulation? Hypothalamus  Briefly summarize the study conducted by Jeffrey Friedman. How did his discovery increase knowledge of obesity? Mice afflicted with severe obesity. Syndrome called ob/ob. First to discover inherited gene mutation. That mutation caused the protein (Leptin) to be made incorrectly and it could not function properly.

Questions  What does the protein leptin tell the brain to do? The more fat a person has, the more the adipose tissue will secrete leptin. Leptin tells the brain to shut down appetite and increase energy expenditure.

Hypothalmus and Leptin  So how would this be different if the leptin protein was mutated?

Questions…  What is the function of the protein MC4R? To promote loss of appetite  What is the function of the protein Alpha- MSH? To promote feeding  How does leptin control these proteins? Leptin triggers MC4R and inhibits MSH

What are your thoughts on the article?