How many calories does 1 gm of fat give?

Appeared in: RRB Nsg. Superintendent-20 July 2019 (Shift-1)

Explanation

Fat is the most energy-dense macronutrient, providing approximately 9 kilocalories (kcal) per gram.
This is more than double the energy provided by carbohydrates or proteins, which each supply about 4 kcal per gram.
The body uses this energy for various metabolic processes, and any excess is stored as adipose tissue.

Option A: This value is factually incorrect. No standard macronutrient provides exactly 8 kcal per gram.
Option C: This is the energy value for carbohydrates and proteins, not fats.
Option D: This value is factually incorrect and does not correspond to any of the major macronutrients.

Visual 1: Bar Chart - A chart comparing the caloric density (kcal/g) of the three macronutrients (fat, protein, carbohydrate) and alcohol. This visually emphasizes that fat provides the most energy per gram.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Caloric value of macronutrients as background academic context rather than a clinical decision trigger.
Understanding the caloric density of fats is crucial for patient education regarding diet and weight management. Since fats provide more than twice the calories per gram compared to proteins and carbohydrates, limiting high-fat foods is a key strategy for creating a caloric deficit for weight loss.
For patients with increased energy needs, such as those with severe burns, cancer cachexia, or cystic fibrosis, a high-fat diet can help provide adequate calories without excessive food volume, which is particularly important for patients with poor appetite or early satiety.
What if? If a patient needs to gain weight but has a poor appetite, a nurse would recommend nutrient-dense, high-fat foods like avocados, nuts, and olive oil, rather than simply large volumes of food. This leverages the high caloric value of fat to meet energy needs efficiently.

How to Approach the Question

This is a factual recall question that tests foundational knowledge in nutrition.
Identify the core of the question: it asks for the specific energy value of fat.
Recall the standard Atwater factors for macronutrients: Fat = 9 kcal/g, Protein = 4 kcal/g, Carbohydrate = 4 kcal/g.
Compare the recalled value for fat (9 kcal/g) with the given options.
Select the option that matches the correct value.

Concept Tested & Keywords

Qb3Pn33ZUuZSeWSmuAHixp

Practise the full RRB Nsg. Superintendent-20 July 2019 (Shift-1)

Attempt every question from this paper in a timed mock, then review the full solution for each one.