For dinner, Charles had one cup of clam chowder, which contains 16g of carbohydrate, 12g of fat, and 9 g of protein. How much energy, in kilocalories and kilojoules, is in the clam chowder? (Round off the answer for each food type to the tensplace.)

Verified step by step guidance

1. Identify the energy contribution per gram for each macronutrient: carbohydrates provide 4 kcal/g, proteins provide 4 kcal/g, and fats provide 9 kcal/g.
2. Calculate the energy from carbohydrates by multiplying the grams of carbohydrates by the energy per gram: 16 g of carbohydrates * 4 kcal/g.
3. Calculate the energy from fats by multiplying the grams of fat by the energy per gram: 12 g of fat * 9 kcal/g.
4. Calculate the energy from proteins by multiplying the grams of protein by the energy per gram: 9 g of protein * 4 kcal/g.
5. Add the energy contributions from carbohydrates, fats, and proteins to find the total energy in kilocalories, then convert the total energy from kilocalories to kilojoules using the conversion factor 1 kcal = 4.184 kJ.

Key Concepts

Macronutrients and Their Energy Values

Macronutrients—carbohydrates, fats, and proteins—are the primary sources of energy in our diet. Each macronutrient provides a specific amount of energy: carbohydrates yield approximately 4 kilocalories per gram, fats provide about 9 kilocalories per gram, and proteins also contribute around 4 kilocalories per gram. Understanding these values is essential for calculating the total energy content of food.

Energy Conversion Units

Energy can be measured in different units, primarily kilocalories (kcal) and kilojoules (kJ). To convert kilocalories to kilojoules, one can use the conversion factor where 1 kcal is approximately equal to 4.184 kJ. This knowledge is crucial for expressing energy content in the desired unit, especially in scientific contexts where different units may be preferred.

Rounding Numbers

Rounding is a mathematical process used to reduce the number of digits in a number while maintaining its approximate value. In this context, rounding to the tens place means adjusting the calculated energy values to the nearest ten. This is important for simplifying results and making them easier to interpret, especially in dietary contexts.