SR.BIOCHEM.2C

BIOLOGY CURRICULUM 2006

NUTRITIONAL VALUE OF FOODS:

INTERPRETING FOOD LABELS

Food supplies our bodies with the matter needed to build living tissue and the energy needed to do work. Energy stored in food is trapped in chemical bonds. Energy is released when these bonds are broken, and then captured again in a form that the body can use. The energy content of foods is measured in calories.

Three of the four organic macromolecules supply us with energy. They are carbohydrates, lipids, and proteins. Carbohydrates provide the body with the most readily available form of energy. More than half of your body’s energy needs should come from carbohydrates such as starches and sugars. Fats provide the body with a energy storage. One gram of fat contains twice as much energy as one gram of carbohydrate. Proteins are also essential nutrients. They also are the body’s only source of nitrogen. Your body needs nitrogen to make amino acids, which are used to build muscles, organs, enzymes, and hormones. Water, vitamins and minerals are nutrients that are also essential to a well-balanced diet.

OBJECTIVE

  • To analyze the nutritional value of foods by interpreting food labels

MATERIALS

  • Nutrition labels from 6 different foods, one of which should be a beverage

PROCEDURE

PART I

  1. Select one food label and write the name of the food in the column labeled Food.
  1. Determine the main type of nutrient(s) that you think the food provides and write it in the column labeled Nutrient(s).
  1. Determine the number of grams per serving of food and write it in the column labeled Grams per Serving.
  2. If necessary, convert ounces to grams by multiplying the serving size by 28.4g/oz. (serving size x 28.4 g/oz)
  1. Calculate the number of calories per gram of food and write it in the column labeled Calories per Gram.
  2. To do this, divide the number of calories by the serving size in grams. (calories ÷ serving size)
  1. Calculate the number of calories per 100 gram sample of the food and write it in the column labeled Calories per 100 Grams.
  2. To do this, multiply calories per gram by 100. (calories per gram x 100)
  1. Repeat steps 1-6 for five additional food labels.

Food / Nutrient(s) / Grams per
Serving / Calories per
Serving / Calories per
Gram / Calories per
100 grams

PART II: Create a graph that compares the Calories per 100-grams of each food item in the table. Be sure to title the graph and label the axes.

ANALYSIS

  1. Which of the foods contains the most calories per serving? The fewest?
  1. Which of the foods provide the most energy per 100 grams?

What is the main type of nutrient(s) found in this food?

  1. Why was it is necessary to convert the measurements to calories per 100 grams?
  1. Why is the calorie content on the food label stated in terms of serving size rather than in terms of a 100-gram sample?
  1. Write down three foods you ate yesterday.
  • What is the main type of nutrient(s) found in each food?
  • Which food do you think provided you with the most energy?

EXTENSION

Nutrition Facts / Amount/Serving / %DV
Serving Size / Total Fat 1g / 2%
56g / Saturated Fat 0g / 0%
Serving Size / Cholesterol 25mg / 8%
2.5 / Sodium 250mg / 10%
Calories / Total Carb. 0g / 0%
70 / Fiber 0g / 0%
Fat Calories / Sugar 0g
10 / Protein 15g / 27%
Vitamin A / 0%
Vitamin C / 0%
Calcium / 0%
Iron / 0%

*Percent Daily Value (DV) are based on a 2000 calorie diet

WHY ARE SOME DIETS NOT HEALTHY?

Carlos loves to eat salmon. Some days, he eats tuna for breakfast, lunch, and dinner! Would a diet that consists of eating only foods from the meat group such as salmon be considered a healthy diet?

Review the label above and use your knowledge of nutrition to explain your answer. (HINT: In your response, identify which nutrients are present and which nutrients are lacking in this diet.)

APPLICATION

You just began a new job as a nutritionist. Your first assignment is to design a “TV Dinner” type of meal. The goal of the assignment is to design a meal that is well-balanced, consisting of each type of nutrient that is important for a healthy diet. Once you decide what foods the meal will include, you will determine the nutritional value of the meal. Finally, you will create a food label for the meal.

To being your assignment, decide what foods the meal will include. Record your choices below:

Main Dish:______

Side Item(s):______

______

______

Dessert:______

Beverage:______

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SR.BIOCHEM.2C

BIOLOGY CURRICULUM 2006

Complete the chart below. Once you do this, you will have the nutritional information needed to complete the nutritional label that will accompany your meal. When you have filled in the information for each food item, determine the total for each column in the chart.

*NOTE: You may need to separate parts of a food product. For example, if you choose to add pizza to your meal, you will have to collect nutritional information on the dough, cheese, sauce and toppings!

Food Item / Serving Size / Calories / Fat / Carbohydrates / Protein / Vitamins / Minerals
TOTAL

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SR.BIOCHEM.2C

BIOLOGY CURRICULUM 2006

You are now ready to complete the nutritional label for your meal. In order to accomplish this, do the following:

  • Enter only the information for those sections that are in BOLD print. Write values on the lines provided.
  • Next to Sodium and Sugar either write HIGH or LOW based upon the foods that you selected. This will be an estimate based upon your discretion. You may wish to consult the Recommended Daily Values as a guide in your decision.
  • In the box labeled Vitamins and Minerals, write all of the vitamins and minerals contained within the foods that you selected for the meal.

When you have completed the activity answer the questions below:

  1. What role does each of the nutrients below play in your body?
  • Carbohydrates:
  • Fats:
  • Proteins:
  • Vitamins:
  • Minerals:
  • Water:
  1. In which foods from the meal you created, are each of these nutrients contained?
  • Carbohydrates:
  • Fats:
  • Proteins:
  • Vitamins:
  • Minerals:
  • Water:
  1. Evaluate the nutritional content of the meal you created. Were you successful in accomplishing the goal of the assignment? Use data from nutritional label to explain why or why not. (Recall that the goal was to design a meal that is well-balanced consisting of each type of nutrient that is important for a healthy diet.)

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