Calculating Energy Needs
How many times have you been confused about how much energy (food!!!) your body truly needs?
Accurately calculating energy needs for active individuals is sometimes confusing and research shows that more times than not needs are UNDER-calculated. Different methods can be used to estimate these needs, with some key differences to note:
Mifflin-St Jeor Equation:
This modern method estimates Basal Metabolic Rate (BMR) and is known for its accuracy, considering current lifestyle and body composition trends.
Harris-Benedict Equation:
An older, well-established method that has been widely used but may sometimes overestimate energy needs, particularly in less active populations. And underestimate active individuals.
Cunningham Equation:
Ideal for athletes and those with higher muscle mass, as it accounts for lean body mass, providing a more personalized energy requirement. This is an equation you need to have results from a DEXA or BIA machine to accurately calculate.
The Role of the Activity Factor:
The Activity Factor (AF) adjusts the BMR based on an individual’s level of physical activity. It ranges from 1.2 for a sedentary lifestyle to 2.5 for very active individuals. By multiplying the BMR by the appropriate AF, we obtain the Total Daily Energy Expenditure (TDEE), which represents the total amount of calories needed per day to maintain current weight, considering both resting and active states.



Underfueling
Failing to meet energy needs, known as underfueling, can have several negative consequences:
- ️Decreased Energy Levels
- Loss of Muscle Mass
- Nutrient Deficiencies
- Impaired Performance
- Hormonal Imbalances
Ensuring accurate energy calculations and adequate caloric intake is essential to avoid underfueling. By understanding and utilizing these equations and factors, a Dietitian can help individuals understand and meet their needs.
Have you ever been told to eat a certain amount of calories and were left fatigued, hungry, injured and defeated? Now is your sign to work with a Dietitian to learn more about how food is FUEL for your body and we all need a different amount based on many factors!
Get More In-Depth With A Nutrition Consultation
Don’t hesitate to reach out if you’d like personalized recommendations or need help troubleshooting your post-workout nutrition plan!
Grace Thomas, MDN, RDN, LDPerformance Dietitian, Personal Trainer, Speed/Agility CoachGracesGrit Nutrition & Fitness Solutions LLC