Metabolic Age: All You Need To Know About

In the linear passage of time, we all age the same. Each orbit around the sun adds another year to our chronological timeline, but when it comes to our bodies, the story gets more complex.

There are different “ageing metrics” beyond chronological age that offer valuable insights into our health such as biological age, metabolic age, and fitness age. 

Consider this analogy - your chronological age is like the car you own. While genetics shape a portion of your biology, much like the car's model, it’s our daily habits and care that profoundly impact our body’s condition and functionality.

Just as you would inspect various components of your car during a check-up, your body has different indicators of health. Some aspects may function optimally, while others may show signs of wear and tear, affecting our overall well-being.

Metabolism, a complex system responsible for converting calories and nutrients from food into energy, undergoes changes as we age.

What is Metabolic Age?

Metabolic age is a measure of how efficiently your body’s metabolism functions compared to others in your age group. It takes into account factors such as your body composition, weight, and other metabolic indicators.

Metabolic age is calculated by comparing your basal metabolic rate (BMR) to the average for your age group. 

What is BMR?

Basal metabolic rate (BMR), a key component of metabolic age, quantifies the energy your body expends at rest. Even when you’re doing nothing, because your cells continuously require energy for basic bodily functions, you’re burning some calories.

BMR is calculated based on factors such as your age, weight, height, and sex.

BMR for men: 66.5 + (13.75 x kg) + (5.003 x cm) – (6.775 x age)

BMR for women: 655.1 + (9.563 x kg) + (1.850 x cm) – (4.676 x age)

Benefits of Knowing Your Metabolic Age

Metabolic age is one metric that can help you assess your overall health and fitness. Because metabolism is a complex system involving various molecules, looking at BMR as a measure of metabolism provides just a partial rather than the entire picture.

Still, it does offer a better undeerstanding of how much energy your body requires on a daily basis. This is especially useful when trying to manage body weight because it helps determine your needed daily caloric intake. 

When we’re younger, our metabolism is generally faster, allowing us to consume more without gaining weight. However, with age, the digestive system tends to slow down, making weight gain more easy. 

Being aware of your metabolic age empowers you to make informed choices about your diet and lifestyle, contributing to better overall health as you navigate the journey of ageing.

How is Metabolic Age Calculated?

You can easily find an online calculator that measures your metabolic age. It calculates your BMR based on your age, height, weight, and sex, and compares it to the average BMR for people of your age. The higher your BMR is, the lower your metabolic age will be!

However, it's important to note that these calculators have limitations. They rely on generalised formulas and don’t consider individual differences in people. BMR is influenced by many factors beyond age and simple body measurements. Our uniqueness, from genetic predispositions and other factors such as hormones, inflammation, stress, and gut microbiome all significantly affect our metabolic rate. 

For a more precise result, professional measurements like indirect calorimetry, are required. This technique measures the body's metabolic rate by analysing respiratory gases, specifically the consumption of oxygen (VO2) and the production of carbon dioxide (CO2).

Factors that Increase Metabolic Age

BMR is influenced by many factors, including:

Age

As we age, our metabolism slows down, primarily due to muscle loss and hormonal changes.

Gender

Men generally have a faster metabolism because of larger body sizes and hormonal differences compared to women.

Genetics

Genetic predispositions can contribute to certain metabolic diseases and food intolerances that, while sometimes lacking evident symptoms, can negatively impact the digestive system and influence metabolism. 

Body fat

Fat tissue has a lower metabolic rate than muscle tissue so it generally burns fewer calories, lowering BMR. Excessive body fat, especially visceral fat (fat around the organs), is associated with insulin resistance, chronic inflammation and hormonal imbalances which all contribute to metabolism disruption. 

Hormones

Various hormones play a role in shaping our metabolism. Thyroid hormones, responsible for cellular energy production, boost our BMR. Pancreatic hormones, like insulin and glucagon, manage how we use and store energy. Stress hormones like cortisol and adrenaline can hike up energy expenditure, however, prolonged stress can lead to metabolic imbalances and potential weight gain.

Physical activity

Physical activity significantly impacts BMR. Individuals leading a sedentary lifestyle often have a lower BMR, which is again linked to hormonal imbalances and excess body fat. Conversely, those engaging in regular physical activity not only burn calories during activities but also train their bodies to burn more calories overall, resulting in a higher BMR.

How to Lower Your Metabolic Age?

There are various ways you can try to lower your metabolic age and raise your BMR. Our bodies are changeable and we can train them to adapt to different lifestyle habits - changes in diet, physical activity, and stress management. 

Eat your protein, time your meals

When eating, our bodies utilise the nutrients from food in the form of proteins, fats, and carbohydrates. As our digestive system breaks down these nutrients, there is an associated increase in energy expenditure known as the thermic effect of food (TEF). Simply, it’s the energy cost associated with metabolising food. 

Out of all the macronutrients, proteins require the most energy to be metabolised and therefore have the highest TEF. They can increase BMR by 20-30%, meaning that 20-30% of the calories contained in proteins are expended during the process of their digestion and metabolism. Carbohydrates, on the other hand, have a lower TEF of around 5-10%, and fats have the lowest TEF ranging from 0-5%. This is why a gram of fat contains more calories than a gram of proteins or carbs.

Incorporating protein-rich foods into your diet not only provides essential nutrients but also helps increase the number of calories burned, contributing to a higher BMR. You can read more about anti-ageing foods on our blog.

Time-restricted eating, a form of fasting, has also been shown to boost metabolism and have positive effects on weight loss and metabolic health. However, prolonged or chronic fasting with severe calorie restriction may lead to a decrease in BMR as a survival mechanism.

Move your body

Regular physical activity is a foundation for good health. In today’s modern world, many people lead sedentary lifestyles, believing that hitting the gym a couple of times a week is enough, but they’re forgetting the basics. Low to moderate activities, like walking, significantly influence our metabolic rate and for most adults, aiming for at least 10,000 steps a day is recommended. Consistent physical activity also helps improve insulin sensitivity, which is crucial for maintaining a healthy metabolism. 

Additionally, engaging in exercise and building muscle mass also helps with metabolic health. As muscle tissue is metabolically more active, it elevates your BMR, resulting in increased calorie burning even when at rest.

Stress less 

A common but often challenging piece of advice - don't stress so much! While easier said than done, the impact of stress on our health is undeniable. Despite being aware of its negative effects, we often prioritise diet or exercise over stress management when trying to “be healthier”. 

Chronic stress can cause hormonal imbalances, triggering a cascade of changes within the body that work against our well-being, including a negative effect on our metabolism. For better health, including your metabolic age, managing stress is crucial, so find what works for you - whether it’s meditation, mindful walks in nature, or punching a boxing bag!

Metabolic Age vs Chronological Age

Chronological age counts the number of years since our birth, progressing at the same pace for everyone. It is a useful and commonly used metric for certain health predictions, given the well-established association between ageing and increased susceptibility to disease and frailty. 

While knowing a person's chronological age provides a baseline for understanding their stage in life, health is a complex and multifaceted concept influenced by various factors. As a result, different systems in the body may function in unique ways, showing various 'ages' from within.

Metabolic age, for example, assesses the efficiency of metabolic functions, specifically how the body utilises energy throughout the day. A higher metabolic age surpassing your chronological age might suggest your body is not functioning optimally, potentially increasing your risk of health issues.

Metabolic Age vs Fitness Age

Fitness age serves as another indicator of your overall health. There are online fitness age tests available for calculating your age, much like those for metabolic age, which compare your metrics to those of your age peers. One of the metrics the test uses is VO2 max, reflecting how well your body utilises oxygen during intense exercise and providing insights into your cardiovascular fitness and endurance. 

While metabolic age offers insights into metabolic efficiency, fitness age focuses on overall physical fitness. Factors like diet and exercise play crucial roles, and having a lower fitness age, much like metabolic age, is associated with a longer lifespan.

Metabolic Age vs Biological Age

Biological age is the ultimate measurement of overall health, offering deeper insights compared to metabolic and fitness age. Biological age tests are very complex, often requiring biological material like saliva or blood samples for age calculations.

There are various biological age tests, but what they have in common is they all focus on at least one of the hallmarks of ageing:

• Genomic instability
• Telomere attrition
• Epigenetic alterations
• Loss of proteostasis
• Deregulated nutrient-sensing
• Mitochondrial dysfunction
• Cellular senescence
• Stem cell exhaustion
• Altered intercellular communication
• Chronic inflammation
• Dysbiosis

Many different tests examine epigenetic alterations, reflecting changes in gene expression over time. Another important hallmark associated with natural ageing is chronic inflammation, marked by a prolonged and dysregulated immune response that can contribute to the development of various diseases. This is what the GlycanAge test focuses on. 

GlycanAge uniquely focuses on measuring your biological age through the lens of the immune system, analysing complex sugars called glycans attached to Immunoglobulin G, the key players in our adaptive immune system.

Unlike epigenetic tests, which are based on information, GlycanAge focuses on molecular effectors of inflammation. These molecules change with ageing, but also they are very reflective of your lifestyle. Healthy habits can reduce the inflammation inside the body, and bad ones can increase it. 

GlycanAge is responsive to various factors beyond genetics, such as diet, exercise, stress, sleep, and other interventions. It offers a personalised approach to your health assessment by showing you how your lifestyle affects your health. It can help you find what’s right for you and effectively measure the positive or negative impact of your daily choices. 

Conclusion

While metabolic age offers valuable insights into metabolic health, it doesn’t provide a comprehensive picture of overall well-being. Quick online questionnaires used to calculate metabolic age don’t take into account individualized differences, offering unreliable results. For a more accurate assessment, professional measurements like indirect calorimetry are needed, yet these too focus on a singular metric for health evaluation. 

For a more insightful look at your body’s health from within, biological age tests are a better option. Although more complex to analyze, these age tests offer a personalised approach to understanding an individual’s health. 

GlycanAge, for instance, is a simple at-home testing kit, requiring just 4 drops of blood, that reflects the impact of your genetics, environment, and lifestyle on your overall well-being. A higher GlycanAge is associated with elevated levels of inflammation, while a lower one indicates an optimised lifestyle and a slower pace of ageing. 

An advantage of biological age is that it can be reversed, and GlycanAge shows responsiveness to changes in diet, physical activity, stress levels, and more.

In a world brimming with health trends, finding out what works for you is difficult, whether it’s a new diet, exercise regimen, or a popular supplement everyone’s telling you to try out. GlycanAge can be your personalized tool, guiding you to explore what works for YOUR health.

You can start by taking a short health quiz to see how your daily habits might affect your Glycan Score!