Using the energy values for foods (see TABLE 3.7), determine each of the following (round off the answer for each food type to the tens place):
a. the total kilojoules in two tablespoons of crunchy peanut butter that contains 6 g of carbohydrate, 16 g of fat, and 7 g of protein

Question

Using the energy values for foods (see TABLE 3.7), determine each of the following (round off the answer for each food type to the tens place):

a. the total kilojoules in two tablespoons of crunchy peanut butter that contains 6 g of carbohydrate, 16 g of fat, and 7 g of protein

Accepted Answer

Welcome back everyone. If the energy values of carbohydrates, fat and protein are 17 kilojoules per gram, 38 kilojoules per gram and 17 kilojoules per gram respectively, calculate the total kilojoules rounded off to the tens place and two tablespoons of cheese spread containing two g of carbohydrates, five g of fat and three g of protein. Now, in order to find our total energy gained from our cheese spread, we're going to set this equal to the sum of energy from the nutrients within Archie's between our carbs gained from it, fats and proteins gained from eating the cheese spread. And so to find the energy equivalent of our nutrients, we would take the mass of our nutrient multiplied by our energy value of our nutrient. So let's begin with our first nutrient being carbs. So our energy of carbs gained from eating the cheese bread would be found by taking our massive carbs being two g of carbs within the cheese bread multiplied by its energy value equivalents as 17 kilojoules per gram in the denominator. So canceling out our unit of grams were left with kilojoules as our unit of energy and we would simplify to find our energy of carbs within the cheese bread equal to 34 kilojoules of energy gained. Now, we're going to determine our total energy of fats within the cheese bread. And so given our mass as five g of fats, we're going to multiply by our energy equivalents being 38 kilojoules per gram of fats, which we can now cancel out our units of grams leaving us with kilojoules of fats. And this would yield an energy value of 190 kilojoules. And last, we have our energy of protein within our cheese spread in which we take our massive protein, three g of protein multiplied by our energy equivalents being 17 kilojoules per gram. And again, canceling out our gram units. We're left with kilojoules of proteins where we'll get our results as 51 kilojoules of proteins gained from eating the cheese bread. So now taking the sum between our energy values of our nutrients, we're going to find the total energy gained from eating our cheese bread in which we take our 34 kilojoules of carbs added to our 190 kilojoules of fats and then added to our 51 kilojoules of proteins all within our cheese spread. And so taking the sum, we would find our total energy equal to 275 kilojoules of energy in total. And this would be our final answer. And actually just, I just remembered that we need to round this off to the 10th place. So this is not going to be our final answer just yet. So since we have a five in R ones place, we're going to round this to about 280 kilojoules of total energy gained from eating our cheese spread. And that will be our final answer to complete this example. So I hope that this made sense and let us know if you have any questions.

Using the energy values for foods (see TABLE 3.7), determine each of the following (round off the answer for each food type to the tens place):
a. the total kilojoules in two tablespoons of crunchy peanut butter that contains 6 g of carbohydrate, 16 g of fat, and 7 g of protein

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Key Concepts

Macronutrient Energy Values

Energy Calculation

Rounding Off Numbers