Lab 5: Nutrition Pre-Lab PDF

**LAB 5: Nutrition** **Pre-Lab** Read the following scenario and answer the questions to follow. **Scenario: Diets to Die For?** "Have you ever wondered about the numerous fad diets that are featured regularly in the media? One of these is based on the theory that eating too many carbohydrates p...

**LAB 5: Nutrition** **Pre-Lab** Read the following scenario and answer the questions to follow. **Scenario: Diets to Die For?** "Have you ever wondered about the numerous fad diets that are featured regularly in the media? One of these is based on the theory that eating too many carbohydrates prevents the body from burning fat and dieters should, therefore, fill up on protein. In the 1970's, The Complete Scarsdale Medical Diet and Dr. Atkins' Diet Revolution hit the scene. Today high-protein-diet books like The Zone and Protein Power are flying out of bookstores, and on an infomercial the Atkins diet business is pushing butter-drenched lobster as diet food. However, protein-rich diets also tend to be chock-full of saturated fat and cholesterol, which can increase the risk of heart disease. Another side effect: When carbohydrate calories are cut drastically for several days, the body starts burning fatty acids for fuel; these release into the bloodstream chemicals called ketones that can cause headaches, dizziness, fatigue, nausea, and bad breath. Too much protein can also tax the kidneys, which over time, may cause permanent damage. On the other hand, the American public has also been besieged with other diet books that recommend high-carbohydrate diets. Examples of these include the Pritikin Diet Plan and the Save-Your-Life Diet. Many of these diet plans claim to cure the ills perceived to be associated with the diets of the western world. They claim to prevent or treat such diseases as high blood pressure, diabetes, gout, atherosclerosis, and gall stones. The American Medical Association has questioned the safety and effectiveness of high-carbohydrate diets, particularly regarding the diseases they are supposed to prevent. At best, research says, they are no better than other diets aimed at preventing peripheral vascular diseases. At worst, they could lead to reduced resistance to infection and poor healing of wounds because of the lower fat and protein intakes. In addition, some of the fattest people in the world base their diets on pasta and bakery products. A high carbohydrate diet based on spaghetti, macaroni, bread and rolls will make you fat, even if it is low in fat and you avoid meat, chicken and dairy products. Cellulose, one type of carbohydrate that is indigestible by humans, is , commonly referred to as "insoluble fiber". Eating adequate amounts of fiber has been shown to reduce one's risk of colon cancer and provide additional health benefits. Unfortunately, the vast majority of pasta and bakery products are made from flour which has had the fiber removed. So which should you believe? The truth is---neither is best. A recent study in the American Journal of Clinical Nutrition shows that high and low-carbohydrate diets offer the same rate of weight loss. The only way that a diet can lower cholesterol and help you to lose weight is when it gets you to take in fewer calories than you burn. So, neither a high-carbohydrate nor a low-carbohydrate diet will help you unless it gets you to eat less food, and the only component of food that makes you feel full without contributing calories is fiber. Thus, the best diet that will control your weight permanently without making you feel hungry is based on high-fiber foods: fruits, vegetables, whole grains and beans. It is also important to include moderate amounts of protein from low-fat sources, such as lean meats." Adapted from [[http://medformation.com/mf/stay.nsf/Nutrition/High\_Protein\_Diets]](http://medformation.com/mf/stay.nsf/Nutrition/High_Protein_Diets) and [[http://homearts.com/ghhealth/07nutrb1.htm.]](http://homearts.com/ghhealth/07nutrb1.htm) **Exercise 9: Human Nutrition** **Introduction** In many ways, biology requires the study of the chemistry of life, since life can be thought of as a series of chemical reactions. To fully understand the biological processes of birth, growth and death, it is vital to understand the basics of cellular chemistry. All of the larger chemical substances that are found in living things fall into one of the following categories: (Biologically Important macromolecules) - - - - You may recognize the first three as important factors in nutrition, see the example of a nutritional label below, as indeed these are necessary in our diet to sustain life. In this exercise, you will be conducting tests to determine the presence of some of these molecules. **Pre-Lab Questions** Answer these questions after reading the scenario at the beginning of this lab. Q1. What are the differences between protein, fat and carbohydrates in terms of their functions in the body? Q2. What is usually the cause of initial rapid weight loss when someone goes on a strict diet? Q3. What are "calories"? **Protocol:** **1.** Visit and follow the on screen quiz to get your daily recommended intake for calories and nutrients. **2.** Click on the "XXX calories" recommendation to see your nutritional intake recommendations **3.** Think about all the food you typically eat in a day and answer the following questions. Q1. How much of each of the main food groups (fruits, vegetables, grains, proteins and fats) is recommended for you? Q2. Thinking about your average diet, do you meet these nutritional needs? Q3. Think about all of the foods you eat in a day. Does this make up a healthful diet? What types of foods do you need to add to your diet? What foods do you need to eat less of or eliminate? Q4. Why do you think nutritionists and health experts recommend only eating fatty and sugary foods sparingly?