How many calories should Morgan eat each day to maintain his weight?

December 18, 2025 •

3 min read

An individual's daily caloric needs can vary significantly, depending on a range of factors including genetics, age, and activity levels. To determine with accuracy how many calories should Morgan eat each day to maintain his weight, one must perform a personalized calculation rather than relying on generic averages.

Quick Summary

This article explains how to calculate an individual's maintenance calories by determining their Basal Metabolic Rate (BMR) and Total Daily Energy Expenditure (TDEE). It outlines the key formulas and factors involved, offering a step-by-step approach to personalize calorie intake for weight maintenance.

Key Points

Start with BMR: First, use the Mifflin-St Jeor formula to calculate your Basal Metabolic Rate (BMR) based on your weight, height, age, and sex.
Calculate TDEE: Multiply your BMR by an activity multiplier (e.g., sedentary, moderate, active) to find your Total Daily Energy Expenditure (TDEE), which is your maintenance calorie goal.
Understand It's an Estimate: The calculated number is a scientific estimate and should be used as a starting point, not a definitive rule.
Monitor and Adjust: After establishing a baseline, track your weight and adjust your calorie intake or activity level over time based on your body's response.
Consider Other Factors: Remember that genetics, muscle mass, hormones, and environmental temperature can also influence your daily calorie needs.

The question of how many calories should Morgan eat to maintain his weight is specific and requires a personalized approach based on scientific formulas rather than a single fixed number. While the average man needs around 2,500 kcal per day, this is a broad estimate. The precise number depends on several key variables, including age, height, weight, sex, and physical activity level. The most accurate estimation involves a two-step process: first, calculating the Basal Metabolic Rate (BMR), and second, using that figure to determine the Total Daily Energy Expenditure (TDEE). This TDEE represents the number of calories needed for weight maintenance.

Step 1: Calculating Morgan's Basal Metabolic Rate (BMR)

BMR is the energy your body expends at rest to perform vital functions like breathing and circulation. The Mifflin-St Jeor equation is a recommended formula for calculating BMR.

For men, the Mifflin-St Jeor formula is: BMR = (10 × weight in kg) + (6.25 × height in cm) – (5 × age in years) + 5.

Using a hypothetical example of a 35-year-old male named Morgan, who is 180 cm tall and weighs 85 kg:

$BMR = (10 \times 85) + (6.25 \times 180) - (5 \times 35) + 5$
$BMR = 850 + 1125 - 175 + 5$
$BMR = 1805$ calories

This calculation provides an estimate of Morgan's daily calorie expenditure at rest.

Step 2: Determining Morgan's Total Daily Energy Expenditure (TDEE)

To find Morgan's TDEE, his BMR is multiplied by an activity multiplier that reflects his daily physical activity level.

Activity multipliers include:

Sedentary: BMR x 1.2
Lightly Active: BMR x 1.375
Moderately Active: BMR x 1.55
Very Active: BMR x 1.725
Extremely Active: BMR x 1.9

If we assume Morgan is moderately active, his TDEE would be:

$TDEE = 1805 \times 1.55$
$TDEE = 2797.75$ calories

Based on this calculation, Morgan's estimated maintenance calorie target is approximately 2,798 calories per day.

The Role of Individual Factors and Adjustments

While the BMR and TDEE calculation provides a starting point, individual factors can influence energy expenditure and require adjustments over time.

Comparison of Factors Affecting TDEE


Factor	Impact on Calorie Needs	Why it matters	Example
Age	Decreases	Metabolism slows down with age.	An older Morgan will likely have a lower TDEE than a younger Morgan with the same stats.
Muscle Mass	Increases	Muscle is more metabolically active than fat.	A Morgan with more muscle will have a higher BMR and TDEE.
Genetics	Variable	Influences metabolic rate.	Individuals with identical stats may have slightly different caloric needs due to genetics.
Hormonal Status	Variable	Conditions like thyroid disorders can alter metabolism.	Hypothyroidism would lower Morgan's BMR.
Environmental Temperature	Variable	The body uses energy to regulate temperature.	Morgan's calorie needs may increase if he's in extreme temperatures.

The Importance of Tracking and Adjusting

Monitoring weight and making adjustments to calorie intake or activity level is crucial for sustainable weight management. Consulting with a healthcare provider or registered dietitian can provide personalized guidance.

Conclusion: A Dynamic and Personalized Approach

To determine how many calories should Morgan eat each day to maintain his weight, a personalized calculation using the Mifflin-St Jeor equation and an activity multiplier is necessary. For our hypothetical Morgan, the estimate is around 2,798 calories per day. However, this is a starting point, and ongoing monitoring and adjustments based on individual factors and weight fluctuations are essential for long-term weight maintenance.

Frequently Asked Questions

BMR (Basal Metabolic Rate) is the minimum number of calories your body needs to function at rest. TDEE (Total Daily Energy Expenditure) is the total calories you burn in a day, which includes your BMR plus the energy from all physical activity.

The Mifflin-St Jeor equation is widely considered one of the most accurate formulas for estimating BMR for the general population and is recommended by the American Dietetic Association.

Morgan should recalculate his maintenance calories whenever there is a significant change in his body weight, activity level, or other relevant factors. This is particularly important after achieving a weight loss goal, as a smaller body requires fewer calories.

Yes, it is possible. Many people maintain their weight by focusing on a balanced diet of nutrient-dense foods, intuitive eating, and regular physical activity rather than strict calorie counting. Calorie calculation is a tool, not a necessity.

Your maintenance calories can decrease due to a natural slowdown in your metabolism with age, a decrease in lean muscle mass, or metabolic adaptation that can occur after significant weight loss.

Both are important, but quality is vital. Consuming nutrient-rich foods provides better health benefits, sustained energy, and helps with satiety, which supports long-term weight maintenance and overall well-being.

The most effective way to increase your maintenance calories is to increase your lean muscle mass through strength and resistance training, as muscle tissue burns more calories at rest than fat tissue.