**Question:** Number of calories in 100 grams of breast milk is: September 2007

**Core Concept:** Calories in breast milk and their composition

**Why the Correct Answer is Right:**

1. **Calories in breast milk:** Breast milk contains energy in the form of carbohydrates, proteins, and fats. The primary energy source for a newborn is fat, followed by carbohydrates, and proteins.

2. **Correct Answer (Option D):** 70 calories. This value represents the approximate calorie content of 100 grams of breast milk, which is derived from the macronutrient composition of breast milk.

3. **Macronutrient composition of breast milk:** Breast milk contains approximately 60% fat, 30% carbohydrates, and 10% proteins.

4. **Why other options are incorrect:**
- Option A (60 calories): This value is incorrect as it underestimates the calorie content of breast milk, which is mainly derived from fat (60%).
- Option B (90 calories): This value is incorrect as it overestimates the calorie content of breast milk, which consists predominantly of fat (60%).
- Option C (100 calories): This value is incorrect as it is equal to the total calorie content of the 100 grams of breast milk, which is derived from the combination of macronutrients.

**Why each wrong option is wrong:**

- Option A (60 calories): This value underestimates the calorie content of breast milk, which is mainly derived from fat (60%). Fat is the primary source of energy in breast milk, contributing to approximately 60% of the total energy content.
- Option B (90 calories): This value overestimates the calorie content of breast milk, which consists predominantly of fat (60%). Fat is the primary source of energy in breast milk, contributing to approximately 60% of the total energy content.
- Option C (100 calories): This value is incorrect as it is equal to the total calorie content of the 100 grams of breast milk, which is derived from the combination of macronutrients. Breast milk is primarily composed of fat (60%), followed by carbohydrates (30%) and proteins (10%).

**Clinical Pearls:**

1. **Macronutrient composition of breast milk:** 60% fat, 30% carbohydrates, and 10% proteins. The macronutrient composition is essential for an understanding of the nutritional content of breast milk and its role in infants' growth and development.
2. **Calories in breast milk:** The primary source of energy in breast milk is fat (60%) followed by carbohydrates (30%) and proteins (10%). This information is crucial for healthcare professionals providing care for infants fed with breast milk.

**Core Concept Explanation:**

Breast milk is a complex mixture of nutrients and bioactive components that support the growth and development of infants. The primary macronutrients in breast milk are fat, carbohydrates, and proteins. Fat