Go back

How old is your body, really? How to improve BMR and metabolic age

Editor’s note: Last month, I tried one of those fancy weighing machines at my friend’s house – which measure much more than just your weight – and was shocked to discover the reading – the machine told me my ‘metabolic age’ was over 40, when I was just in my early thirties! (Compare this to my friend – whose metabolic age turned out to be in her late twenties, despite being the same age as me.)

Now, I’ve been hearing the term ‘metabolic age’ being tossed around in conversations, especially on my Instagram feed, without really knowing what it means. But this was a rude awakening – it was high time I delved deeper into what it meant.

Basal Metabolic Rate (BMR) & metabolic age: what’s the connection?

As I did more research, I realized that metabolic age is calculated on one primary metric: the Basal Metabolic rate or BMR. Your BMR is the number of calories your body needs to perform basic functions like breathing, absorbing nutrients from food and converting them into energy (metabolism), maintaining blood circulation, etc.

There are several factors that influence BMR – primary among them is your age. With age, our metabolic rate starts to drop, which then lowers BMR. Why? Because as we grow older, we tend to become less active, leading to fewer calories burnt during the day; we tend to lose more muscle (an average adult loses around 7-8% of their muscle mass every decade after thirty); and our nerve impulses tend to slow down.

There are a number of other factors that affect BMR besides age – such as gender and your body composition (how much fat-free mass you have, for example – which is your body weight minus your body fat).

Here’s a quick calculation that’s often used for calculating BMR, if you want to try it out:

Male: 66.5 + (13.75 x kg) + (5.003 x cm) – (6.775 x age)

Female: 655.1 + (9.563 x kg) + (1.850 x cm) – (4.676 x age)

Metabolic age is the measure of your BMR compared to others in your age group. The higher your BMR, the lower your metabolic age. Simply put, it’s a scorecard – and at over 40, my BMR was equivalent to those significantly older than me rather than those in my chronological age group.

BMR, TDEE and RMR – what’s the difference?

There were two other terms I came across in my research. The first was TDEE – or the Total Daily Energy Expenditure. Your BMR is not the number of calories you need in a day – it’s only the basic minimum amount of calories your body needs to function. TDEE can give you a good idea of the number of calories you need in a day. TDEE is calculated by multiplying your BMR with an activity level factor (that is, how active you are through your day. For example, for me at my desk job, the activity factor is very low as compared to someone who does moderate exercise 4-5 times a week).

The other term I came across was resting metabolic rate (RMR). Although BMR and RMR are calculated differently, the difference between them is negligible – and the terms are often used interchangeably.

So what does having a higher metabolic age actually mean?

Generally speaking, a lower metabolic age than your chronological age is an indicator of overall good health. It implies a more efficient metabolism, typically associated with better health, better body composition (muscle v/s fat ratio in the body), lower blood pressure, general energy levels – the works. If your metabolic age is lower than your chronological age, On the other hand, a higher metabolic age suggests your body might not be as healthy as it could be for someone of your chronological age.

How is metabolic age calculated?

Calculating metabolic age can be somewhat tricky. There are several calculators online and on fitness apps that give you your ‘metabolic age’ – like the fancy weighing machine I tried at my friend’s. These usually estimate your metabolic age based on your BMR and personal data such as height, weight, and age. But while these calculators provide a quick and easy way to gauge your metabolic health, they give estimated values.

If you’re looking for complete accuracy, it might be harder to nail down. The latest research around metabolic age calculated the metabolic age of its participants by developing a special software to measure it over a 5-day period – and took into account participants body composition, resting blood pressure, waist circumference and a number of other factors. Plus, since metabolic age is a relative number – you need data of people in your age bracket with similar ethnographic factors – to get a true picture of metabolic age.

Of course, since I had none of this at my disposal, I decided to get an indirect calorimetry test done to accurately estimate my BMR – which was the key indicator for metabolic age. There are two ways to measure BMR: direct and indirect calorimetry tests. Direct calorimetry is a method in which you spend time in a controlled room with little to no movement. While this is accurate, it’s obviously not for general use. Indirect calorimetry is when you use a device to measure the If you’re looking for the most accurate number, then you’ll want to visit a clinic that offers direct or indirect calorimetry. This process involves using a device to measure oxygen intake and carbon dioxide output to assess the calorie burning efficiency of your body. The results were in line with my first assessment – I needed to up my metabolic age game!

Improving metabolic age

Now that I had made up my mind about improving my metabolic age – I dug deeper into the how of it. I realised that I had to combat the natural slowdown of my metabolism with age (that begins to happen in your mid-thirties).

Simply losing weight – and I admit, I have a few extra kgs – was not enough, because if you restrict calories, your body goes into starvation mode and slows down your metabolism, instead of increasing it. The trick was to add in exercise, while making changes to your diet and being at a caloric deficit – so that my muscle mass could improve and my fat levels went down – increasing my overall BMR.

So here’s what I tried:

I added HITT & strength training to my routine

Building muscle mass is a big factor to improving metabolic age. Muscles are more metabolically active than fat – that is, your body uses more energy to work muscles, which is why a higher muscle composition leads to a higher BMR, and a lower metabolic rate. While cardio (in the form of walking) was something I was fairly regular with, I started adding in high-intensity interval training (HIIT) and lifting weights to my routine, both of which helps build muscle mass. (I would recommend checking in with your trainer first – especially if you haven’t done HIIT before.)

I upped my protein intake

Protein intake supports muscle growth – especially when you couple it with strength training. Plus protein ranks the highest in the thermic effect of food (TEF) – that is, the number of calories your body uses to break it down, which further helps in boosting BMR and lowering metabolic age. I made sure to increase the quantities of lean cuts of meat, eggs, fish and legumes in my diet.

I made sure to get more sleep

I had read that getting a good night’s sleep has an important role to play in your metabolism levels, and inadequate sleep can also lead to weight gain. To combat that I started tracking my sleep meticulously and made sure to get around 8 hours every day.

I incorporated more water and tea in my diet

Incredibly, increasing your water intake can actually increase your body’s calorie consumption – studies have shown that drinking 500 ml of water increased metabolic rate by 30% for around 30-40 minutes. In fact, drinking around 2.5 litres of water a day could lead to a significant amount of resting calorie loss – and it might be even greater if you drink cold water! I also read that green tea and oolong tea could also lead to minor boosts in metabolism – and hey, who doesn’t love a nice cup of tea? These were both minimal things that I could very easily incorporate in my diet.

Takeaway

Overall, a couple of months into making these shifts in my diet and exercise, I started noticing improvements. I had significantly better energy levels, lost a couple of kilos, and found that, overall, eating better and exercising more regularly improved my mood. Was my metabolic age better than my friend’s yet? No. But was it better than before? Certainly.

The important thing to remember is that your metabolic age is not the ‘gold star’ of your fitness levels – it’s still a fairly new marker and research is ongoing on it. But treated in cohesion with other fitness markers – it can be a good guide to determine some underlying metabolic issues of your body.

Want to help someone who is looking to try new health innovations? Share this article with them.

Over 20,000 customers have reduced their symptoms and improved their health by consulting Shyft's Clinical Nutritionists. When are you starting?

Click here to begin

Continue to read on a range of topics related to Exercise, Nutrition, Mental Health and Sleep Health.

The Gut-Check: The Impact of Skipping Meals

4 minutes

05 Aug 2023

The Gut-Check: The Impact of Skipping Meals

Think twice before skipping that meal, as it could very well be the key to unlocking the secrets of a healthy gut! From aiding in digestion and absorption of nutrients to supporting our immune system and even influencing our mood and mental health, the gut microbiome is a complex and fascinating part of our bodies. But did you know that one simple habit, like skipping meals, can have a significant impact on this delicate balance of bacteria in our gut?… Read more

Editor’s pick

Gut Health, Nutrition,

The Gut-Check: The Impact of Skipping Meals

4 minutes

05 Aug 2023

Editor’s pick

Taste the Rainbow: The Delicious Benefits of Eating Colourful Fruits and Veggies

3 minutes

05 Apr 2023

Taste the Rainbow: The Delicious Benefits of Eating Colourful Fruits and Veggies

Nutrition,

Eating a variety of colourful fruits and vegetables is not only visually appealing but also provides numerous health benefits. The colours of fruits and vegetables indicate the presence of certain nutrients, and consuming a diverse range of colours ensures that you get a well-rounded mix of nutrients. In this blog, we will explore the benefits of eating a rainbow of fruits and vegetables as a holistic way of healthy eating. Red Fruits and Vegetables: A Burst of Antioxidants Red fruits… Read more

Nutrition,

Taste the Rainbow: The Delicious Benefits of Eating Colourful Fruits and Veggies

3 minutes

05 Apr 2023

Managing Holiday Weight Gain: Myths v/s Realities

7 minutes

22 Dec 2023

Managing Holiday Weight Gain: Myths v/s Realities

Weight Loss, Nutrition, Wellness,

December marks the height of the holiday season - with Christmas, end-of-year celebrations, weddings and general festive spirit. But it also brings in a challenge familiar to those of us who are trying to manage weight gain or stick to consistent nutrition routines: holiday weight gain. If you’re finding it difficult to keep on track of your health and fitness goals this time of year, you’re not alone. Is holiday weight gain real? Unfortunately, yes. Research has shown that most… Read more

Editor’s pick

Weight Loss, Nutrition, Wellness,

Managing Holiday Weight Gain: Myths v/s Realities

7 minutes

22 Dec 2023

Editor’s pick

Change up your diet in your 30s (you can thank us later!)

4 minutes

26 Apr 2023

Change up your diet in your 30s (you can thank us later!)

Nutrition,

Age, they say, is just a number. While we would not disagree, our bodies, with their biological clocks ticking, might. There are numerous changes that occur as you age, so it becomes important to change your habits to keep up with the body. Just making small changes in what and how you eat can go a long way in helping you stay healthy for years to come. Understanding bodily changes that happen during your 30s You are definitely ageing like… Read more

Change up your diet in your 30s (you can thank us later!)

4 minutes

26 Apr 2023

Healthwatch by Shyft

How old is your body, really? How to improve BMR and metabolic age

Read more

Keep Exploring