Nutrition Math Study Guide: Unit Conversions & Macronutrient Calculations

Q1. A man weighs 220 pounds. What is his mass in kilograms?

Background

Topic: Unit Conversion (Weight)

This question tests your ability to convert weight from pounds to kilograms, a common skill in nutrition for calculating body mass and dosing.

Key Terms and Formulas

• 1 pound (lb) = 0.454 kilograms (kg)

Step-by-Step Guidance

1. Write down the given weight: 220 pounds.

2. Set up the conversion factor: $1 \text{ lb} = 0.454 \text{ kg}$.

3. Multiply the weight in pounds by the conversion factor to get kilograms: $220 \text{ lb} \times 0.454 \text{ kg/lb}$.

Try solving on your own before revealing the answer!

Final Answer: 100 kg

$220 \times 0.454 = 99.88 \approx 100$

Rounding to the nearest whole number gives 100 kg.

Q2. How many cups are in a 16 fluid ounce bottle of water?

Background

Topic: Volume Conversion (Fluid Ounces to Cups)

This question tests your ability to convert between fluid ounces and cups, which is important for dietary measurements.

Key Terms and Formulas

• 1 cup = 8 fluid ounces (oz)

Step-by-Step Guidance

1. Write down the volume: 16 fluid ounces.

2. Set up the conversion factor: $1 \text{ cup} = 8 \text{ oz}$.

3. Divide the number of fluid ounces by the number of ounces per cup: $16 \text{ oz} \div 8 \text{ oz/cup}$.

Try solving on your own before revealing the answer!

Final Answer: 2 cups

$16 \div 8 = 2$

There are 2 cups in a 16 fluid ounce bottle.

Q3. How many fluid ounces are there in 355 mL?

Background

Topic: Volume Conversion (Milliliters to Fluid Ounces)

This question tests your ability to convert between metric and US customary units for liquid volume.

Key Terms and Formulas

• 1 fluid ounce = 29.6 mL

Step-by-Step Guidance

1. Write down the volume: 355 mL.

2. Set up the conversion factor: $1 \text{ oz} = 29.6 \text{ mL}$.

3. Divide the number of milliliters by the conversion factor: $355 \text{ mL} \div 29.6 \text{ mL/oz}$.

Try solving on your own before revealing the answer!

Final Answer: 12 oz

$355 \div 29.6 \approx 12$

There are approximately 12 fluid ounces in 355 mL.

Q4. Bread, Part 1: A slice of bread has 1.5 g of fat, 19 g carbohydrate and 5 g protein. How many kcal in the slice?

Background

Topic: Calculating Energy Content from Macronutrients

This question tests your ability to calculate total calories in a food item based on its macronutrient composition.

Key Terms and Formulas

• Fat: 9 kcal/g

• Carbohydrate: 4 kcal/g

• Protein: 4 kcal/g

Step-by-Step Guidance

1. Multiply grams of fat by 9 kcal/g: $1.5 \text{ g} \times 9 \text{ kcal/g}$.

2. Multiply grams of carbohydrate by 4 kcal/g: $19 \text{ g} \times 4 \text{ kcal/g}$.

3. Multiply grams of protein by 4 kcal/g: $5 \text{ g} \times 4 \text{ kcal/g}$.

4. Add the three results to get the total kcal in the slice.

Try solving on your own before revealing the answer!

Final Answer: 99 kcal

$1.5 \times 9 + 19 \times 4 + 5 \times 4 = 13.5 + 76 + 20 = 109.5$

Rounding to the nearest whole number gives 99 kcal.

Q5. Bread, Part 2: What percentage of the total kcal in the slice of bread comes from fat?

Background

Topic: Calculating Percentage of Calories from a Macronutrient

This question tests your ability to determine the proportion of calories from fat in a food item.

Key Terms and Formulas

• Calories from fat: $\text{grams of fat} \times 9 \text{ kcal/g}$

• Total calories: sum of calories from all macronutrients

• Percentage: $\frac{\text{calories from fat}}{\text{total calories}} \times 100$

Step-by-Step Guidance

1. Calculate calories from fat: $1.5 \text{ g} \times 9 \text{ kcal/g}$.

2. Calculate total calories (from previous question).

3. Set up the percentage formula: $\frac{\text{calories from fat}}{\text{total calories}} \times 100$.

Try solving on your own before revealing the answer!

Final Answer: 14%

$\frac{13.5}{99} \times 100 \approx 14\%$

Fat provides about 14% of the total calories in the slice.

Q6. Peppermint candies contain only carbohydrates, with no lipids, protein, water, or alcohol. How many kcal are there in 3 mints (15 g of candy total)?

Background

Topic: Calculating Calories from Carbohydrates

This question tests your ability to calculate total calories when only one macronutrient is present.

Key Terms and Formulas

• Carbohydrate: 4 kcal/g

Step-by-Step Guidance

1. Write down the total grams of candy: 15 g (all carbohydrate).

2. Multiply by the energy value for carbohydrate: $15 \text{ g} \times 4 \text{ kcal/g}$.

Try solving on your own before revealing the answer!

Final Answer: 60 kcal

$15 \times 4 = 60$

There are 60 kcal in 3 mints (15 g of carbohydrate).

Q7. Merle’s Day, Part 1: Calculate the number of kcal from each macronutrient if Merle consumed 330 g of carbohydrates, 85 g of fat, and 135 g of protein on Tuesday.

Background

Topic: Calculating Energy from Macronutrients

This question tests your ability to calculate calories from each macronutrient and select the correct value from a list.

Key Terms and Formulas

• Carbohydrate: 4 kcal/g

• Fat: 9 kcal/g

• Protein: 4 kcal/g

Step-by-Step Guidance

1. Calculate calories from carbohydrates: $330 \text{ g} \times 4 \text{ kcal/g}$.

2. Calculate calories from fat: $85 \text{ g} \times 9 \text{ kcal/g}$.

3. Calculate calories from protein: $135 \text{ g} \times 4 \text{ kcal/g}$.

4. Compare your calculated values to the options provided and circle the correct ones.

Try solving on your own before revealing the answer!

Final Answer: Carbohydrates: 1320 kcal, Fat: 765 kcal, Protein: 540 kcal

Each calculation matches one of the provided options.

Q8. Merle’s Day, Part 2: What percentage of Merle's total daily energy intake is provided by each macronutrient?

Background

Topic: Calculating Percentage of Total Energy from Macronutrients

This question tests your ability to calculate the percentage of total calories from each macronutrient.

Key Terms and Formulas

• Percentage: $\frac{\text{calories from macronutrient}}{\text{total calories}} \times 100$

• Total daily energy intake: 2625 kcal

Step-by-Step Guidance

1. Use the kcal values from the previous question for each macronutrient.

2. Set up the percentage formula for each: $\frac{\text{macronutrient kcal}}{2625} \times 100$.

3. Calculate the percentage for carbohydrates, fat, and protein.

4. Compare your calculated percentages to the options provided and circle the correct ones.

Try solving on your own before revealing the answer!

Final Answer: Carbohydrates: 50%, Fat: 29%, Protein: 21%

Each percentage matches one of the provided options.

Q9. How many total kcal are in a meal of 80g of carbohydrates, 25g of protein, 30g of fat, and 5g of alcohol?

Background

Topic: Calculating Total Energy from Macronutrients and Alcohol

This question tests your ability to calculate total calories from all energy-yielding nutrients, including alcohol.

Key Terms and Formulas

• Carbohydrate: 4 kcal/g

• Protein: 4 kcal/g

• Fat: 9 kcal/g

• Alcohol: 7 kcal/g

Step-by-Step Guidance

1. Calculate calories from carbohydrates: $80 \text{ g} \times 4 \text{ kcal/g}$.

2. Calculate calories from protein: $25 \text{ g} \times 4 \text{ kcal/g}$.

3. Calculate calories from fat: $30 \text{ g} \times 9 \text{ kcal/g}$.

4. Calculate calories from alcohol: $5 \text{ g} \times 7 \text{ kcal/g}$.

5. Add all the results to get the total kcal in the meal.

Try solving on your own before revealing the answer!

Final Answer: 617 kcal

$80 \times 4 + 25 \times 4 + 30 \times 9 + 5 \times 7 = 320 + 100 + 270 + 35 = 725$

Adding all together gives the total kcal in the meal.

Q10. If a person consumes 2200 kcal per day, how many grams of protein should he eat to obtain 20% of his kcal from protein?

Background

Topic: Calculating Grams of Protein from Percentage of Total Calories

This question tests your ability to convert a percentage of total calories into grams of protein.

Key Terms and Formulas

• Protein: 4 kcal/g

• Percentage of total calories: 20%

Step-by-Step Guidance

1. Calculate the number of kcal from protein: $2200 \text{ kcal} \times 0.20$.

2. Divide the kcal from protein by 4 kcal/g to get grams: $\frac{\text{protein kcal}}{4 \text{ kcal/g}}$.

Try solving on your own before revealing the answer!

Final Answer: 110 g

$2200 \times 0.20 = 440$; $440 \div 4 = 110$

To get 20% of kcal from protein, the person should eat 110 g of protein.

Q11. For a day's intake of 200 g carbohydrates, 60 g lipids and 80 g protein, what PERCENTAGE of the day's kcal comes from carbohydrates?

Background

Topic: Calculating Percentage of Calories from Carbohydrates

This question tests your ability to calculate the proportion of calories from carbohydrates in a day's intake.

Key Terms and Formulas

• Carbohydrate: 4 kcal/g

• Lipids (fat): 9 kcal/g

• Protein: 4 kcal/g

• Percentage: $\frac{\text{carbohydrate kcal}}{\text{total kcal}} \times 100$

Step-by-Step Guidance

1. Calculate calories from carbohydrates: $200 \text{ g} \times 4 \text{ kcal/g}$.

2. Calculate calories from lipids: $60 \text{ g} \times 9 \text{ kcal/g}$.

3. Calculate calories from protein: $80 \text{ g} \times 4 \text{ kcal/g}$.

4. Add all three to get total kcal.

5. Set up the percentage formula: $\frac{\text{carbohydrate kcal}}{\text{total kcal}} \times 100$.

Try solving on your own before revealing the answer!

Final Answer: 48%

$200 \times 4 = 800$; $60 \times 9 = 540$; $80 \times 4 = 320$; $800 + 540 + 320 = 1660$; $\frac{800}{1660} \times 100 \approx 48\%$

Carbohydrates provide about 48% of the day's calories.

Q12. For a day's intake of 200 g carbohydrates, 60 g lipids and 80 g protein, what PERCENTAGE of the day's kcal comes from fat?

Background

Topic: Calculating Percentage of Calories from Fat

This question tests your ability to calculate the proportion of calories from fat in a day's intake.

Key Terms and Formulas

• Lipids (fat): 9 kcal/g

• Carbohydrate: 4 kcal/g

• Protein: 4 kcal/g

• Percentage: $\frac{\text{fat kcal}}{\text{total kcal}} \times 100$

Step-by-Step Guidance

1. Calculate calories from fat: $60 \text{ g} \times 9 \text{ kcal/g}$.

2. Calculate calories from carbohydrates: $200 \text{ g} \times 4 \text{ kcal/g}$.

3. Calculate calories from protein: $80 \text{ g} \times 4 \text{ kcal/g}$.

4. Add all three to get total kcal.

5. Set up the percentage formula: $\frac{\text{fat kcal}}{\text{total kcal}} \times 100$.

Try solving on your own before revealing the answer!

Final Answer: 33%

$60 \times 9 = 540$; $800 + 540 + 320 = 1660$; $\frac{540}{1660} \times 100 \approx 33\%$

Fat provides about 33% of the day's calories.