How Many Calories Do You Need if You're Not Moving?

January 8, 2026 •

4 min read

According to the Cleveland Clinic, your body's basal metabolic rate (BMR) accounts for 60-70% of your total daily energy expenditure. This means you burn a significant number of calories even in a state of total rest, which is the precise answer to how many calories do you need if you're not moving.

Quick Summary

This article explains how to determine your baseline calorie requirements for a sedentary lifestyle, focusing on the concept of Basal Metabolic Rate (BMR). It details the Mifflin-St Jeor formula and discusses key factors affecting your resting energy burn, from age and gender to body composition. It also outlines the health implications of inactivity.

Key Points

Basal Metabolic Rate (BMR) is your core need: BMR is the energy your body uses for fundamental functions like breathing and circulation, accounting for 60-70% of total daily energy burn.
Calculate your BMR for a baseline: Use formulas like the Mifflin-St Jeor equation, which requires your weight, height, age, and sex, to estimate your resting calorie needs.
Apply an activity multiplier for sedentary needs: Multiply your BMR by 1.2 to estimate the calories required for a sedentary, inactive lifestyle.
Muscle mass is crucial for a higher BMR: As muscle tissue is more metabolically active than fat, increasing lean body mass can raise your BMR, helping you burn more calories at rest.
Inactivity has severe health consequences: Beyond just weight gain, a prolonged sedentary lifestyle significantly increases risks for heart disease, diabetes, certain cancers, and mental health issues.
Movement mitigates risks, even in small amounts: Breaking up long periods of sitting with light activity improves metabolism and circulation, countering some of the negative effects of a sedentary life.

Understanding Your Body's Baseline Energy Needs

Your body is a complex engine that constantly requires energy to power its most fundamental life-sustaining functions. This includes things you don’t even think about, like breathing, circulating blood, cellular repair, and maintaining body temperature. The number of calories required to perform these basic tasks in a state of complete rest is known as your Basal Metabolic Rate (BMR). For most people, this accounts for the majority of their daily energy expenditure, making it the essential starting point for determining your needs when your physical activity is minimal.

The Science Behind Your Resting Calorie Burn

Scientifically, BMR is measured under very strict conditions: a darkened room, a reclining position, and following a fasting period to ensure no energy is being used for digestion. Since this is impractical for most people, several formulas exist to estimate BMR. The Mifflin-St Jeor equation is widely considered one of the most accurate predictive equations for modern lifestyles.

How to Calculate Your BMR: The Mifflin-St Jeor Equation

The Mifflin-St Jeor equation provides a more precise estimate of your BMR by considering your weight, height, age, and sex.

For men, the formula is: $BMR = (10 \times \text{weight in kg}) + (6.25 \times \text{height in cm}) - (5 \times \text{age in years}) + 5$

For women, the formula is: $BMR = (10 \times \text{weight in kg}) + (6.25 \times \text{height in cm}) - (5 \times \text{age in years}) - 161$

Moving from BMR to Sedentary Calorie Needs

Once you have your BMR, you need to adjust it based on your activity level to find your Total Daily Energy Expenditure (TDEE). For someone who is truly inactive or sedentary, with little to no exercise, the multiplier is 1.2.

Example for a Sedentary Woman: If a 35-year-old woman is 165 cm tall and weighs 68 kg, her BMR would be approximately 1400 kcal/day. If she is sedentary, her TDEE would be: $1400 \times 1.2 = 1680$ calories per day. This is the estimated amount she needs to maintain her weight while not moving much.
Example for a Sedentary Man: If a 35-year-old man is 178 cm tall and weighs 85 kg, his BMR would be approximately 1770 kcal/day. For a sedentary lifestyle, his TDEE would be: $1770 \times 1.2 = 2124$ calories per day.

Factors that Influence Your Basal Metabolic Rate

Your BMR is not a fixed number and several factors contribute to its variability. Understanding these can help you better manage your energy needs.

Key BMR Influencers

Body Composition: This is the most important factor. Muscle tissue is more metabolically active than fat tissue, meaning it burns more calories at rest. Therefore, individuals with higher lean muscle mass have a higher BMR.
Age: BMR generally decreases with age. This is often linked to a natural decline in muscle mass and other hormonal changes that occur over time.
Gender: Men typically have a higher BMR than women of the same age and weight. This is due to men's generally higher muscle mass and lower body fat percentage.
Genetics: Some people are genetically predisposed to have a faster or slower metabolism, which can influence their BMR.
Hormonal Health: Hormones, especially those produced by the thyroid gland, are primary regulators of metabolism. An underactive thyroid (hypothyroidism) can significantly lower BMR.

The Dangers of Prolonged Inactivity

While knowing your resting calorie needs is important for balance, a sedentary lifestyle carries significant health risks beyond just weight management. Long periods of inactivity can increase the risk of serious health conditions, including:

Obesity and metabolic syndrome
Heart disease, high blood pressure, and high cholesterol
Type 2 diabetes
Certain cancers, such as colon, breast, and uterine cancer
Osteoporosis and weakened bones
Poor circulation and muscle weakness
Increased feelings of anxiety and depression

Even if you meet daily physical activity goals, prolonged periods of sitting are associated with poor health outcomes. Interrupting sedentary time with short bouts of light activity can have meaningful health benefits.

BMR Calculation Methods: A Quick Comparison


Feature	Mifflin-St Jeor Equation	Harris-Benedict Equation	Katch-McArdle Formula
Accuracy	Generally considered the most accurate for modern individuals.	A historically common method; tends to be less accurate than Mifflin-St Jeor.	Considered most accurate for individuals who are leaner and know their body fat percentage.
Data Required	Weight (kg), Height (cm), Age (years), Sex.	Weight (kg or lbs), Height (cm or inches), Age (years), Sex.	Lean Body Mass (kg) or Body Fat %.
Pros	High accuracy for general population, uses metric units for precision.	Widely known and available, both imperial and metric options exist.	Accounts for body composition, making it ideal for athletes.
Cons	Requires metric inputs for standard formula.	Less accurate than newer formulas, can overestimate needs for some.	Requires knowing your body fat percentage, which can be difficult to measure accurately.

Conclusion: Mindful Living, Even When Resting

Understanding your basal metabolic rate is a powerful tool for weight management, but it is just one piece of the puzzle. The calories you need if you're not moving are essential, but true health extends far beyond this baseline number. A sedentary lifestyle, even with a perfectly balanced diet, poses significant risks to your long-term well-being. Therefore, while calculating your BMR and adjusting for minimal activity is a great starting point for understanding your energy needs, it should serve as a motivator to incorporate more movement into your daily routine. Even light activity, like taking the stairs or standing for part of your workday, can have a cumulative positive impact that improves circulation, metabolism, and overall health. The goal is not just to survive on a low number of calories but to use your energy wisely to live a more active, vibrant life, protecting your body from the dangers of prolonged inactivity. For personalized health advice, including nutritional planning and exercise recommendations, it is always best to consult with a healthcare provider or a registered dietitian.

[Disclaimer: The information provided is for educational purposes only and should not be considered medical advice.]

Frequently Asked Questions

BMR (Basal Metabolic Rate) is the minimum energy required to sustain life at total rest, while RMR (Resting Metabolic Rate) includes the energy burned during low-effort daily activities and digestion. RMR is typically about 10% higher than BMR.

Online calculators that use equations like Mifflin-St Jeor are a good starting point, but they provide estimates. For the most accurate measurement, lab-based tests like indirect calorimetry are needed, though these are not widely available.

Yes. Eating too few calories for an extended period can cause your metabolism to slow down as your body tries to conserve energy. Additionally, your body uses energy to digest food, with protein having a higher 'thermic effect' than fats or carbs.

The most effective way to increase your BMR is by building and maintaining lean muscle mass through resistance training. Muscle tissue burns more calories at rest than fat tissue.

Men tend to have a higher BMR primarily due to a higher ratio of muscle mass to body fat compared to women. Muscle is more metabolically active, which leads to a higher resting energy burn.

While it's possible for short-term weight loss under medical supervision, very low-calorie diets are often not recommended long-term. They can slow metabolism, cause nutrient deficiencies, and lead to other health risks.

BMR naturally decreases with age, often because of a gradual decline in muscle mass. Hormonal and neurological changes with aging can also contribute to a slower metabolism.