What is the formula for calculating Basal Metabolic Rate (BMR)?

The formula for calculating Basal Metabolic Rate (BMR) involves using body weight and a conversion factor to estimate the energy expenditure of the body at rest. The correct answer accurately reflects this process by including an essential multiplier, which considers the caloric value of energy in terms of kilojoules or calories.

In this context, the multiplier of 4.2 is significant because it represents the number of kilojoules in one calorie (specifically based on the conversion between these two units of energy). Therefore, by calculating body weight in kilograms, multiplying by 24 to represent the number of hours in a day, and then multiplying by 4.2, you arrive at an estimate of daily energy expenditure in kilojoules, assuming no activity beyond basic physiological needs.

This formula is widely accepted in nutritional science as it provides a more comprehensive assessment of energy needs over the course of a day when a person is at rest, which is crucial for dietary planning and understanding metabolic health. It highlights the relationship between an individual's body weight and their energy requirements due to various biological processes, such as maintaining body temperature, organ function, and cellular activities.