The body’s metabolic rate varies depending on age, gender, genetics, and lifestyle. Recent studies highlight the importance of focusing on the metabolic rate, calorie burn, and their relationship with weight management and fat loss. While some people consider the link between metabolism and age speculative, understanding these terms is key to improving your health. Let’s start with the basics.

What is the Metabolic Rate?

The metabolic rate, also called Basal Metabolic Rate (BMR), is divided into three main components:

Basal Metabolic Rate (BMR)

This is the number of calories your body needs to perform its vital functions while at rest, without any extra effort. These calories are consumed to sustain life and energy balance during rest.

At rest, your body still performs essential functions such as:

• Circulation
• Breathing
• Digestion

Thermal Effect of Food (TEF)

This is a temporary rise in metabolism after eating. The effect differs depending on the type of food:

• Proteins: Highest thermal effect (20–30%).
  Example: If chicken has 200 calories, its thermal effect is 40–60 calories.
• Carbohydrates: Moderate effect (5–15%).
  Example: If rice has 200 calories, its thermal effect is 10–30 calories.
• Fats: Lowest effect (0–3%).
  Example: If butter has 200 calories, its thermal effect is less than 10 calories.

Energy Expenditure During Physical Activity

Your body burns calories by oxidizing proteins, carbohydrates, and fats from the food you eat to generate energy for movement and exercise.

Because energy stores in the body are limited, energy is regenerated in two ways:

• Aerobic metabolism: Requires oxygen, uses proteins, carbs, and fats.
• Anaerobic metabolism: Doesn’t require oxygen, mainly uses carbohydrates.

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Natural Metabolic Rate for Women

Women generally have a lower metabolic rate compared to men.

• Adult women: 1,600–2,200 calories/day
• Adult men: 2,200–3,000 calories/da

Factors Affecting Women’s Metabolic Rate

• Pregnancy: Increases calorie needs.
• Breastfeeding: Burns more calories compared to non-breastfeeding women.
• Daily activity: Active individuals burn more calories than sedentary ones.
• Body composition: More muscle mass = higher metabolism, even at rest.

How to Calculate Basal Metabolic Rate (BMR) for Women

The BMR is the largest part of your metabolism, representing calories burned at rest.

Formula:
BMR = (10 × weight) + (6.25 × height) – (5 × age) – 161

This shows how many calories your body burns daily at rest.

Calculating Total Daily Energy Expenditure (TDEE)

Your body burns not only fat but also carbs and proteins. Energy use depends on activity level:

• Rest/low intensity: Burns mostly fat.
• High intensity: Burns more carbs than fat and protein.

Physical activity levels are categorized as:

• Sedentary: 1.2
• Light activity (1–3 days/week): 1.375
• Moderate activity (3–5 days/week): 1.55
• High activity (6–7 days/week): 1.725
• Very high activity (multiple intense workouts/day): 1.9

Formula:
TDEE = BMR × Activity Factor

Practical Steps for Weight Loss

1. Calculate your BMR.
2. Multiply BMR × activity factor to get TDEE.
3. Subtract 15–25% of calories from TDEE.
4. Add regular physical activity.

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Comparing Metabolism with Age

Metabolism slows down with age. Let’s compare women’s calorie needs by age:

• Ages 19–31: 1,800–2,000 calories/day
• Ages 31–51: About 1,800 calories/day

How Do You Know if Your Metabolism is High or Low?

Basal metabolism accounts for 60–70% of daily energy use, influenced by:

• Lifestyle: diet, calorie intake, physical activity
• Age: declines with age
• Gender: higher in men
• Ethnicity: sweat levels and body response
• Body composition: muscle mass increases metabolism
• Genetics: inherited traits
• Weight fluctuations history

About 10% of daily energy comes from TEF.

Metabolic Age Calculation

To know if your metabolism is high or low, compare your metabolic age with your real age.

• If metabolic age > real age → metabolism is lower than normal.
• If metabolic age < real age → metabolism is healthier and more efficient.

How to Improve Metabolism

• Increase physical activity: Exercise regularly.
• Build muscle mass: More muscle = higher calorie burn at rest.
• Eat protein: High thermal effect boosts metabolism.
• Reduce stress: Chronic stress raises cortisol, slowing metabolism.
• Get enough sleep: 7–9 hours per night

💡 Understanding metabolism helps you build a healthier lifestyle by identifying your body’s real needs instead of following random diets. The best part? Your metabolism is not fixed—you can improve it with the right habits.