Using the energy values for foods (see TABLE3.7), 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 7g of protein

Verified step by step guidance

1. Identify the energy values for each macronutrient: carbohydrates, fats, and proteins. Typically, carbohydrates and proteins provide 17 kJ/g, while fats provide 37 kJ/g.
2. Calculate the energy contribution from carbohydrates by multiplying the grams of carbohydrates by the energy value per gram: \(6 \, \text{g} \times 17 \, \text{kJ/g}\).
3. Calculate the energy contribution from fats by multiplying the grams of fat by the energy value per gram: \(16 \, \text{g} \times 37 \, \text{kJ/g}\).
4. Calculate the energy contribution from proteins by multiplying the grams of protein by the energy value per gram: \(7 \, \text{g} \times 17 \, \text{kJ/g}\).
5. Add the energy contributions from carbohydrates, fats, and proteins to find the total energy content in kilojoules, and round the result to the nearest tens place.

Key Concepts

Caloric Values of Macronutrients

Each macronutrient provides a specific amount of energy: carbohydrates and proteins yield approximately 17 kJ (4 kcal) per gram, while fats provide about 37 kJ (9 kcal) per gram. Understanding these values is essential for calculating the total energy content of food based on its macronutrient composition.

Energy Calculation

To determine the total energy in a food item, multiply the grams of each macronutrient by its respective energy value and then sum these products. This process allows for a comprehensive understanding of how much energy a specific quantity of food provides.

Rounding Off Numbers

Rounding is a mathematical technique used to simplify numbers to a specified degree of accuracy. In this context, rounding off the total energy value to the nearest tens place helps in presenting the final answer in a clear and manageable format, which is often required in scientific reporting.