Question

Calculate the Cal (kcal) in \(1 / 2\) cup of soft ice cream that contains \(18 \mathrm{~g}\) of carbohydrate, \(11 \mathrm{~g}\) of fat, and \(4 \mathrm{~g}\) of protein. (Round off the kilocalories to the tens place.)

Short answer

190 kilocalories

Step-by-step solution

Identify Caloric Values per Gram

Carbohydrates provide 4 kilocalories per gram, proteins provide 4 kilocalories per gram, and fats provide 9 kilocalories per gram.

Calculate Carbohydrates' Contribution

Multiply the grams of carbohydrates by the caloric value per gram: \( 18 \text{ g} \times 4 \text{ kcal/g} = 72 \text{ kcal} \)

Calculate Fats' Contribution

Multiply the grams of fats by the caloric value per gram: \( 11 \text{ g} \times 9 \text{ kcal/g} = 99 \text{ kcal} \)

Calculate Proteins' Contribution

Multiply the grams of protein by the caloric value per gram: \( 4 \text{ g} \times 4 \text{ kcal/g} = 16 \text{ kcal} \)

Sum Total Calories

Add the kilocalories from carbohydrates, fats, and proteins: \( 72 \text{ kcal} + 99 \text{ kcal} + 16 \text{ kcal} = 187 \text{ kcal} \)

Round Off to the Tens Place

Round 187 kilocalories to the nearest tens place: 190 kilocalories.

Key concepts

caloric values of macronutrients

Understanding caloric values of macronutrients is crucial for calculating the nutritional content of food. Macronutrients—carbohydrates, fats, and proteins—each provide a specific amount of energy per gram.
This energy is measured in kilocalories (kcal), often simply called calories.
Here's a quick guide:

• Carbohydrates: 4 kcal per gram
• Proteins: 4 kcal per gram
• Fats: 9 kcal per gram

These values help us figure out how many calories we are consuming from different macronutrients in our food.

carbohydrate caloric contribution

Carbohydrates are one of the primary sources of energy in our diet. To calculate the caloric contribution of carbohydrates, multiply the number of grams of carbs by their caloric value.
For example, if you have 18 grams of carbohydrates, you calculate the energy like this:
\[ 18 \text{ g} \times 4 \text{ kcal/g} = 72 \text{ kcal} \]
This tells us that 18 grams of carbohydrates contribute 72 kilocalories to the total energy content.

fat caloric contribution

Fats are more calorie-dense than carbohydrates or proteins, providing more energy per gram. To find out the calorie contribution from fats, you multiply the grams of fat by their caloric value.
For example, if you have 11 grams of fat:
\[ 11 \text{ g} \times 9 \text{ kcal/g} = 99 \text{ kcal} \]
So, 11 grams of fat add 99 kilocalories to the total. Because fats are high in calories, they can significantly impact the overall energy content of a meal.

protein caloric contribution

Proteins are essential for building and repairing tissues and also provide energy. Similar to carbohydrates, proteins offer 4 kcal per gram. To compute the caloric contribution from proteins, follow this calculation:
Suppose you have 4 grams of protein:
\[ 4 \text{ g} \times 4 \text{ kcal/g} = 16 \text{ kcal} \]
This means that 4 grams of protein contribute 16 kilocalories to the total calorie count of the food.

rounding off calories

Once you have calculated the total kilocalories from all macronutrients, the next step is to round off the total to make it simpler to understand.
In our exercise, we added the kilocalories from carbohydrates (72 kcal), fats (99 kcal), and proteins (16 kcal), getting a sum of 187 kilocalories.
To round this off to the nearest tens place, we look at the digit in the ones place (7 in this case). Since it is 5 or greater, we round up:
\[ 187 \text{ kcal} \rightarrow 190 \text{ kcal} \]
This simplification makes it easier to keep track of your daily caloric intake.