How to Determine Metabolic Age?
Metabolic age is a health metric that compares your basal metabolic rate (BMR) to the average BMR of others in your age group. Unlike chronological age, metabolic age is based on how efficiently your body uses energy and performs key functions.
A metabolic age that’s higher than your actual age may point to lifestyle habits or health markers that could use improvement. Meanwhile, a lower metabolic age often indicates better-than-average physical health.
In this article, we’ll explain what metabolic age is, why it matters and how you can find out yours. Plus, we’ll share practical steps to help improve your metabolic age and support your long-term health.
What is metabolic age and why does it matter?
Metabolic age gives you an idea of how your body compares to others of the same age based on factors like muscle mass, body fat and resting metabolic rate. It’s a useful marker of how efficiently your body is working and can offer insight into your overall health and fitness levels.
While it’s not a medical diagnosis, having a metabolic age that is significantly higher than your actual age may be a sign that your body is under strain - potentially due to lifestyle factors like poor diet, lack of physical activity or excess visceral fat. In contrast, a lower metabolic age can reflect a healthier body composition and improved physical resilience.
Understanding your metabolic age can help you spot areas for improvement and track the impact of any positive lifestyle changes over time.
Key factors that influence your metabolic age
Your metabolic age is shaped by a combination of internal and external factors - some you can influence, others you can’t. Understanding what plays a role can help you make changes that support a healthier, more efficient metabolism over time.
Here are some of the key contributors:
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Body composition Muscle tissue is more metabolically active than fat, meaning it burns more energy even when you're at rest. A higher muscle-to-fat ratio typically supports a lower metabolic age.
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Physical activity Staying active helps increase your daily energy expenditure and encourages the body to maintain lean muscle. Both structured exercise and general movement, like walking or taking the stairs, can make a difference.
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Nutritional balance What you eat matters. Diets rich in protein, fibre, healthy fats and micronutrients can help regulate metabolic function. However, excessive intake of processed foods may contribute to inefficiency.
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Hydration Water plays a crucial role in nearly every metabolic process. Dehydration can slow things down, making it harder for your body to perform optimally.
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Hormonal health Hormones such as insulin, cortisol and thyroid hormones all influence how your body uses and stores energy. Disruptions in hormone balance, due to stress, medical conditions or lifestyle, can impact metabolic age.
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Sleep quality Deep, restorative sleep helps regulate the systems that control energy use and recovery. Regular poor sleep can interfere with these processes, leading to slower metabolism over time.
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Age and biological sex While you can’t change these factors, they do affect your baseline metabolic rate. However, healthy habits can still help offset natural declines and support better overall function.
How metabolic age is measured: the tools and methods
Metabolic age is typically assessed using your BMR - the number of calories your body burns at rest to maintain vital functions like breathing, circulation and cell production. Once your BMR is calculated, it’s compared to population averages across different age groups to estimate your metabolic age.
There are a few common ways this measurement is carried out:
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Body composition analysis This is one of the most reliable ways to assess metabolic age. It looks at the ratio of fat to lean tissue in your body, helping determine how much energy you burn at rest. These scans often include measurements like BMR, metabolic age, body fat percentage and visceral fat levels.
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Bioelectrical impedance devices Frequently used in gyms and health assessments, these scales send a low-level electrical current through the body to estimate body composition. While not as precise as clinical methods, they offer a quick and non-invasive snapshot.
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Health assessments and screenings Comprehensive check-ups, such as the Complete Health MOT, combine body composition analysis with other health markers - like cholesterol, blood sugar and blood pressure - for a more complete picture of your metabolic health.
These tools not only estimate your metabolic age but also highlight areas for improvement, offering a clearer view of how your body is functioning beyond the numbers on a scale.
The role of diet and exercise in shaping your metabolic age
Two of the most influential factors when it comes to your metabolic age are how you eat and how you move. Both play a direct role in how efficiently your body generates energy and maintains essential functions.
How diet can support a healthier metabolic age
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Choose whole, nutrient-dense foods A balanced diet rich in lean protein, fibre, healthy fats and complex carbohydrates helps fuel your body and maintain lean muscle - both important for a more favourable metabolic age.
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Avoid highly processed options Diets high in refined sugars, unhealthy fats and additives can slow down metabolism and lead to increased fat storage, which may raise your metabolic age.
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Stay hydrated Water supports digestion and energy production, and even mild dehydration can reduce your metabolic efficiency.
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Don’t skip meals Regular, balanced meals help regulate blood sugar levels and keep your metabolism functioning steadily throughout the day.
Why exercise matters
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Build lean muscle Muscle tissue burns more calories than fat, even at rest. Strength training helps increase muscle mass, which can lower your metabolic age.
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Keep active consistently Cardiovascular activity supports heart health and boosts metabolism, while everyday movement, like walking or cycling, keeps energy use steady throughout the day.
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Mix it up Combining strength, cardio and flexibility exercises helps support overall body function and improves how efficiently you burn energy.
Together, a nutritious diet and regular physical activity create the foundation for a healthier, more resilient body - and a more youthful metabolic age.
How accurate are metabolic age calculators?
Metabolic age calculators can provide a helpful benchmark, but their accuracy depends on the method used and the data they’re based on.
Many online tools offer quick estimates using basic information like age, height, weight and activity level. While these can give a general idea, they don’t account for body composition - specifically, how much muscle and fat your body contains, which plays a significant role in metabolic function.
More advanced assessments, such as those included in health checks like the Complete Health MOT from Bluecrest Wellness, use body composition analysis to deliver a more accurate result. These scans measure factors like:
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Basal metabolic rate (BMR): The number of calories your body needs at rest.
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Muscle and fat distribution: A key factor in how efficiently your body burns energy.
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Visceral fat levels: Fat stored around your organs, which can affect metabolic health. While no single calculation can tell the full story, having a precise, data-led picture of your metabolic age is a useful tool for understanding how your lifestyle is influencing your health, and where you might benefit from making changes.
Use your metabolic age to guide health improvements
Understanding your metabolic age can offer a valuable perspective on your overall health and how your body is functioning beneath the surface. Whether it’s higher or lower than your actual age, the number serves as a guide - not a judgement - helping you make more informed decisions about your diet, activity levels and lifestyle habits.
If you're looking to take a proactive approach to your health, the Complete Health MOT from Bluecrest Wellness includes a body composition scan that calculates your metabolic age, alongside other key health insights. With your results, you’ll be equipped to track progress, spot areas for improvement and make meaningful changes to support long-term wellbeing.
