By the end of this lab, you will be able to:

  • Given a food nutritional label, calculate the % of Calories from a specific macronutrient
  • Distinguish between Calories and nutrients
  • Apply the principles from Canada’s Food Guide to evaluate a meal in terms of proportions, types of macronutrients present, and eating habits

Required prior knowledge and textbook readings:

Introduction:

Animals are heterotrophs, as they must consume food in order to gain energy and nutrients to be used by their cells. In this lab, you will analyze food labels and Canada’s Food Guide to understand and evaluate Calories and nutrients in different food items or meals.

Part 1: Calories

One of the important functions of our diet is to supply the molecules that will eventually be converted into glucose and used in cellular respiration. The energy that is stored in food is converted into ATP by mitochondria in our cells and eventually used by the cells to do work. The energy stored in food is measured in calories.  One calorie of energy is equal to the energy required to heat 1 g of water by 1°C. The Calories that nutritionists refer to are actually kiloCalories (1000 Calories) and are written as Calories (capital C).

Each food item has its own unique range of chemical constituents, three of which are what are considered macronutrients. These are chemicals that can be broken down by the body and used as energy. Each macronutrient can give the body a different amount of energy (Calories) (see Table 1 below).

Table 1.  Caloric equivalent of carbohydrates, proteins, and fats.

Nutrient Cal/g
carbohydrates 4
proteins 4
fats 9

 

From Table 1, we can see that for every gram of carbohydrate we consume, we gain 4 Calories. For every gram of protein we consume, we gain 4 Calories, and for every gram of fats we consume, we gain 9 Calories.

We can calculate the percentage of Calories coming from these macronutrients for a particular food item based on information from the nutritional label:

Example: 1 serving of Ritz Crackers is 130 Calories.
There are 4 g of fat in one serving. 
4 g fat x 9 C/g (taken from Table 1)= 36 C from fats
36 C/130 C x 100% = 28% of Calories are coming from fats

[INSERT H5P ACTIVITY WITH ONE OR TWO OF THESE CALCULATIONS]

Try a few more calculations for extra practice! Using the nutritional label from a food package of your choice, determine the % of Calories coming from each of the three macronutrients.

 

Part 2: Nutrients

Food is not just an energy source. What you eat is a complex mixture of hundreds of different chemical constituents in order to provide your cells with the building blocks they need to create organelles, hormones, proteins, DNA, and more. Nutrients such as fats, carbohydrates, and proteins are important to take in, in addition to vitamins and minerals that act as co-enzymes or help build tissues.

1. Visit this website to view Canada’s Food Guide. Note that this version of the guide has switched the focus from serving sizes to eating balanced meals.

[INSERT H5P ACTIVITY ABOUT HALF BEING FRUIT/VEG, QUARTER BEING PROTEIN, QUARTER BEING WHOLE GRAINS]

2. Visit the Healthy Food Choices page of Canada’s Food Guide website, and follow the instructions below to explore the information within.

a. Start by clicking on ‘Eat plenty of vegetables and fruits, whole grain foods and protein foods.’ Read some of the benefits of health eating and of eating more plant-based food.

b. On the left hand side, click on ‘Eat plenty of vegetables and fruits‘. Read about the important nutrients found in vegetables and fruits.

c. Now click on ‘Eat whole grain foods‘. Read about the important nutrients found in whole grains as compared to refined grains, and look at the examples of whole grains.

d. Now click on ‘Eat protein foods‘. Read about why proteins are good for you, and why it is important to eat more plant-based protein. Think about which plant-based proteins you may already be eating or want to eat more of.

e. Now click on ‘Choosing foods with healthy fats‘ and read the information. Review examples of saturated and unsaturated fats.

[INSERT H5P ACTIVITY TO REVIEW THE DIFFERENCE BETWEEN A SATURATED AND UNSATURATED FAT]

f. Now spend a bit of time browsing the other links in this section: ‘Limit highly processed foods‘, ‘Make water your drink of choice’, ‘Use food labels‘, and ‘Be aware of food marketing‘.

3. Go back to the home page and click on ‘Healthy eating habits‘. In this version of Canada’s Food Guide, healthy eating is not just about what you eat, but it is about mindful eating habits, placing emphasis on home cooking, enjoying your meals, and the importance of eating with others. As you review this information, consider how it relates to your own eating habits or anything new that you’ve learned.

 

Assignment:

If required by your instructor, you can download the assignment for the Nutrition lab Nutrition Lab Assignment. Note that the file download works best using Microsoft Edge or Mozilla Firefox web browsers (not Google Chrome). Once you have completed the assignment, submit the file to your instructor as per their instructions.