What’s Your Metabolic Age? Learn Why It’s An Important Tracker, How You Compare, and Ways to Improve It

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Julien Raby

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Let’s delve into the essence of metabolic age, a concept that transcends traditional health metrics like BMI. It’s not just about the years you’ve lived, but how efficiently your body functions.

Discover the intricate balance between your chronological age and metabolic age, and how factors like diet, exercise, and lifestyle choices can significantly influence this vital health indicator.

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Learn the art of calculating your metabolic age, using tools ranging from online calculators to bioelectrical impedance scales.

Uncover the profound impact of metabolic age on your overall health, and explore actionable strategies to turn back your metabolic clock.

Definition of Metabolic Age

In the realm of fitness and health, metabolic age stands as a pivotal concept, often overshadowed by more familiar terms like BMI or calorie count. Yet, it’s a crucial indicator of overall well-being, offering insights far beyond what conventional metrics provide.

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Metabolic Age Concept

Metabolic age dives deep into the body’s operational efficiency. It’s a measure, not of years lived, but of how effectively your body functions compared to an average person of your chronological age.


Think of it as a health scoreboard, reflecting the vitality of your body’s metabolic processes – from burning calories to energy production.

A Complex Calculation

Calculating metabolic age isn’t as straightforward as checking a calendar. It involves comparing your Basal Metabolic Rate (BMR) – the number of calories your body needs to perform basic life-sustaining functions – with the average BMR for your age group.

Tools like bioelectrical impedance scales come in handy here, offering a glimpse into your body’s composition and, by extension, its metabolic efficiency.

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Chronological Age vs. Metabolic Age

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Chronological age is a straightforward count of the years since your birth. Metabolic age, however, tells a more nuanced story. It’s a tale of how lifestyle choices, exercise habits, and nutritional intake shape your body’s internal workings.

Two individuals might share the same chronological age, yet their metabolic ages can differ significantly. A 30-year-old with a sedentary lifestyle, poor dietary habits, and high body fat percentage might have a metabolic age closer to 40. Conversely, another 30-year-old, committed to regular Crossfit sessions, balanced nutrition, and a healthy body composition, could boast a metabolic age of 25.

Individuals with younger relative metabolic age had significantly lower body weight, body mass index, body fat mass, and waist circumference on average.


This disparity highlights a crucial point: Metabolic age is malleable. Unlike the relentless march of chronological years, you can influence your metabolic age. Regular exercise, particularly high-intensity workouts like Crossfit, coupled with a nutrient-rich diet, can turn back your metabolic clock, fostering a body that’s younger on the inside than the calendar suggests.

Factors Affecting Metabolic Age

Basal Metabolic Rate (BMR)

At the heart of metabolic age lies Basal Metabolic Rate (BMR), a key player. BMR represents the number of calories your body needs to perform basic functions while at rest. It’s like the idle speed of a car’s engine. Higher BMR means your body needs more energy for basic functions, often indicating a healthier metabolism.

Factors like muscle mass, age, and gender significantly influence BMR. For instance, more muscle mass typically equates to a higher BMR.

Body Composition: Fat vs. Muscle

Body composition, particularly the ratio of fat mass to lean muscle, is crucial. Muscle tissue burns more calories than fat, even when you’re not moving. Therefore, a body composition with a higher percentage of lean muscle usually signals a younger metabolic age.

This is where strength training and muscle-building exercises, like those in Crossfit, play a vital role.

Lifestyle Choices

Lifestyle factors are pivotal in determining metabolic age. Physical activity levels are at the forefront. Regular exercise, especially high-intensity workouts, can boost your BMR, leading to a younger metabolic age.

Sleep patterns also play a role; poor sleep can slow down metabolism. Stress levels are another factor; chronic stress can negatively impact your metabolic rate.

Nutrition, too, is key. Diets rich in protein and healthy fats can enhance metabolism, while high-sugar, high-carb diets might do the opposite.

Age and Weight

As we age, our BMR naturally decreases, which can increase metabolic age. Weight also plays a role; excess weight can lower BMR, leading to a higher metabolic age. However, this isn’t a one-way street. With the right lifestyle changes, you can improve these factors.

Hormones and Genetics

Hormones significantly impact metabolism. Thyroid hormones, for example, regulate BMR. Imbalances can lead to metabolic age discrepancies. Genetics also play a role, though they’re not the final word.

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While you might be genetically predisposed to a certain metabolic rate, lifestyle choices can greatly influence your metabolic age.

How to Calculate Metabolic Age

Online Metabolic Age Calculators

Online metabolic age calculators offer a fast and user-friendly way to estimate your metabolic age. These tools typically require inputs like age, gender, height, weight, and activity level. They use this data to estimate your Basal Metabolic Rate (BMR) and compare it with the average BMR for your age group.

While convenient, remember these calculators provide estimates and may not account for individual variations in muscle mass or body composition.

Metabolic age calculator
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Bioelectrical Impedance Scales

For a more accurate assessment, bioelectrical impedance scales are the go-to. These advanced scales not only measure weight but also provide detailed insights into body composition, including muscle mass, fat percentage, and water content.

They estimate BMR by analyzing how easily electrical signals travel through your body – a process influenced by the amount of muscle and fat. More muscle and less fat typically mean a better conductivity and a healthier metabolic age.

Comparing with Average BMR

The crux of calculating metabolic age lies in comparing your BMR to the average BMR of your chronological age group. This comparison reveals whether your body is functioning younger, older, or right on par with your actual age.

For instance, if your BMR is higher than the average for your age group, your metabolic age might be lower than your chronological age, suggesting a healthier, more efficient metabolism.

Calculate Your Average BMR

Calculating your Basal Metabolic Rate (BMR) is a key step in understanding your body’s energy needs. BMR is the number of calories your body requires to perform basic life-sustaining functions, like breathing and maintaining body temperature, while at rest. Here’s how you can calculate it:

For men: 66.47 + (6.24 × weight in pounds) + (12.7 × height in inches) − (6.75 × age in years).
For women: BMR = 65.51 + (4.35 × weight in pounds) + (4.7 × height in inches) – (4.7 × age in years)

Harris-Benedict Calculator (Basal Metabolic Rate)

Importance of Metabolic Age

Metabolic age serves as a revealing mirror, reflecting the state of your metabolic health. It goes beyond mere numbers on a scale, offering a deeper insight into how efficiently your body converts food into energy.

A younger metabolic age often correlates with a higher basal metabolic rate (BMR), indicating a body that’s adept at burning calories. This efficiency is crucial, as it’s linked to reduced risks of obesity, type 2 diabetes, and cardiovascular diseases.

For fitness enthusiasts and everyday health seekers alike, metabolic age can be a key indicator of how well their lifestyle aligns with their health goals.

Predictive Power

Beyond its current snapshot, metabolic age can also act as a predictor of potential health issues. An older metabolic age might signal underlying problems like sluggish metabolism or poor muscle-to-fat ratio, often precursors to more serious health concerns.

By keeping an eye on this metric, individuals can take proactive steps to adjust their diet, exercise, and lifestyle habits, potentially warding off future health complications.

Critique and Context

While metabolic age is a valuable tool, it’s not without its criticisms and limitations. One key critique is its potential oversimplification of health. Metabolic age is based on generalizations and may not account for individual differences in genetics, hormone levels, or unique health conditions.

Additionally, it’s important to remember that metabolic age is just one piece of the health puzzle. It should be considered alongside other factors like blood pressure, cholesterol levels, and overall physical and mental well-being.

Ways to Improve Metabolic Age

Dietary Changes

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Improving metabolic age starts with what’s on your plate. Increasing protein intake is key, as protein boosts metabolism more than carbs or fats and aids in muscle building.

Reducing overall calorie intake, especially from refined carbohydrates, is equally important. These carbs spike blood sugar levels, leading to fat storage and a sluggish metabolism.

Instead, focus on a balanced diet rich in whole foods, vegetables, and healthy fats to fuel your metabolic fire.

In evaluating diet composition, individuals with advanced relative metabolic age reported greater cravings for fat-rich foods, and consumed greater amounts of pork and cold cuts/sausages. Conversely, individuals with a younger relative metabolic age consumed significantly more grains, lauric acid, meat alternative, a greater percentage of calories from polyunsaturated fatty acids, and trended toward consuming greater amounts of vegetable protein.


Exercise More

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Exercise is a powerhouse when it comes to rejuvenating metabolic age. Building lean body mass is crucial, as muscle burns more calories at rest than fat.

Incorporate strength training into your routine, focusing on compound movements that target multiple muscle groups. High-intensity workouts, like those found in Crossfit, are also highly effective.

They not only build muscle but also create a lasting increase in BMR, known as the afterburn effect.

Metabolic Training

Metabolic training is a specific type of high-intensity workout designed to boost metabolism and improve metabolic age. These workouts typically involve short bursts of intense activity followed by brief rest periods.

This approach not only burns a significant amount of calories during the session but also keeps your metabolism elevated for hours afterward. Incorporating metabolic training into your fitness regimen can be a game-changer for improving metabolic age.


  • https://pubs.acs.org/doi/10.1021/acs.jproteome.5b00561
  • https://www.jpep.endocrinology.org.ua/index.php/1/article/view/944
  • https://www.sciencedirect.com/science/article/pii/S2475299123151973?via%3Dihub

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Julien Raby is the owner of BoxLife. He owns a bachelor in literature and a certificate in marketing from Concordia. He's Crossfit Level 1 certified and has been involved in Crossfit since 2010. In 2023 he finally made it to Crossfit Open Quarterfinals for the first time. LinkedIn Instagram Facebook

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