How much calorie is provided by 1 gm protein?

Appeared in: BSF Staff Nurse - 2021

Explanation

According to the standard Atwater system for calculating food energy, 1 gram of protein provides 4 kilocalories (kcal).
Proteins are essential macronutrients for building body tissues and can also be used as an energy source.
This value is the same as that for carbohydrates, which also provide 4 kcal per gram.
The term 'KCL' in the option is a common abbreviation for kilocalories (kcal).

Option B: 9 kcal is the energy provided by 1 gram of fat, which is more than double the energy from protein or carbohydrates.
Option C: 6 kcal per gram is not a standard caloric value for any of the three main macronutrients (protein, fat, carbohydrate).
Option D: 1 kcal per gram is an incorrect and significantly underestimated value for the energy content of protein.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Caloric value of protein as background academic context rather than a clinical decision trigger.
Nurses use these caloric values daily to perform nutritional assessments and calculate a patient's total energy intake.
This knowledge is critical when planning diets, managing enteral (tube) feeding, or calculating formulations for Total Parenteral Nutrition (TPN).
Patient education regarding diet and weight management relies heavily on understanding the different energy contributions of protein, fat, and carbohydrates.

How to Approach the Question

This is a factual recall question.
Identify the core concept being tested: the energy content of protein.
Recall the standard caloric values for macronutrients, known as the Atwater factors.
Remember that both protein and carbohydrates provide 4 kcal per gram.
Remember that fat provides 9 kcal per gram.
Select the option that matches the known value for protein.

Concept Tested & Keywords

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E6 Nutrition Monika Sharma 3e p. 50-52

E6 Medicine Harrison 22e Part 2 p. 502-504

E6 Parks TextBook of Preventive & Social Medicine part 2 — Subpart A (pp 1-232 of 464) p. 169-171

Practise the full BSF Staff Nurse - 2021

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