A slow metabolism is often blamed for weight gain as we age, but does metabolism actually slow down as we get older?
The science of metabolism may be more complex than simply attributing difficulty with weight loss to a slow metabolic rate.
This article will explore the science behind metabolism, the factors that influence it, and how we can maintain a healthy metabolic rate throughout our lives.
What Exactly is Metabolism?
Metabolism is the process of describing the speed at which our bodies utilize food for energy.
Specifically, metabolism refers to the chemical processes your body uses to convert food into energy.
The energy derived from our food fuels everything from your heartbeat, breath, and daily movements. Our body's energy can be divided into Basal Metabolic Rate (BMR) and Activity Energy Expenditure.
Basal metabolic rate refers to the energy that our body utilizes to perform involuntary body functions like circulation and cell repair. Basal metabolic rate is the energy that we burn at rest.
On the other hand, activity energy expenditure refers to the energy we burn through physical activity such as walking, cleaning your apartment, or intentional exercise.
What Factors Contribute to Your Metabolism?
Metabolic rate is influenced by various factors including genetics, age, and body composition. Hormonal health and digestive health can also play a role in metabolic rate.
The following sections will outline the various elements that determine your metabolic rate, along with key details of how these elements play a role in metabolism.
Genetics
Genetics can play a large role in how fast or slow your metabolism is. While there are actions anyone can take to help improve their metabolic health, there are some aspects of metabolism that are genetically programmed.
Muscle Mass
It’s known that individuals with a higher muscle mass burn more calories at rest. Therefore, if someone has a body composition that has a high muscle to fat ratio, it’s likely that their metabolic rate will be faster than someone with a lower muscle to fat ratio.
Age
Age can absolutely play a role in how quickly the body processes energy. While age in and of itself can be a factor for a slower metabolism, it’s also important to consider other factors such as reduced physical activity that might lead to a reduction in muscle mass and therefore metabolic rate.
Hormones
In addition to genetics, age, and changes in muscle mass, hormonal health plays a big part in metabolism. Changes in hormones, specifically thyroid hormones can definitely influence metabolism, either making it slower or faster.
Stress hormones such as cortisol can also directly impact metabolism, interfering with the normal energy conversion process.
Physical Activity
Of course physical activity impacts metabolism as well. The more active you are, the more calories your body burns.
Resistance exercise in particular has lasting effects on metabolism beyond just the calories burned at the time of exercise. Research suggests that metabolic rate can be elevated for hours after a strength training session (1).
Fast vs Slow Metabolisms: Are There Differences?
The idea of having a “fast” or “slow” metabolism is often overstated. While there are variations between individuals, they are typically not as dramatic as we might think.
For most people, metabolism accounts for only a small portion of the difference in body weight. Factors like diet, exercise, and lifestyle habits often play a bigger role.
Does Metabolism Really Slow As We Age?
In short, the answer is yes, metabolism does really slow as we age. However, the change is quite gradual and depends on various factors. In other words, it’s possible to somewhat resist the slowing of your metabolic rate by engaging in healthy habits such as increasing physical activity and taking care of your hormonal health.
Metabolism tends to slow as we age for three main reasons: reductions in muscle mass, hormonal changes, and lifestyle factors.
The following sections will explain how each of these factors can cause a slow down in metabolism.
Reduced Muscle Mass Causes Slowed Metabolism
As we age, the body experiences something called sarcopenia, which refers to the natural loss in muscle mass.
When the body is at rest, muscle tissue burns more energy than fat tissue. Therefore, when we have less muscle mass, our metabolism tends to slow down.
Hormonal Changes and Metabolic Rate
Hormones can change as we age which also influences metabolism. Specifically, sex hormones like testosterone and estrogen can drop which leads to reduced muscle mass and slowed metabolic rate.
Lifestyle Factors that Impact Metabolism
Many people become less active when they get older for various reasons. Whether they’re busy with work, taking care of family members, or experiencing health issues, it’s common for physical activity to take a back seat.
However, reduced physical activity lowers calorie expenditure and can lead to weight gain.
Muscle and Metabolism: Is there a Connection?
The link between muscle and metabolism has everything to do with the fact that muscle tissue is more metabolically active than fat. This means that muscle tissue burns more calories at rest than fat does.
Ensuring a healthy muscle mass or even to increase muscle mass is crucial for supporting a healthy metabolism.
There are a few key tips to keep in mind to support your muscle mass: include strength training, ensure adequate protein intake, and make sure you’re eating enough energy on a daily basis.
Strength Training Can Increase Metabolism
Engaging in regular strength training can both help preserve and build new muscle tissue. Many studies suggest that people who participate in regular resistance training can boost their basal metabolic rate (2).
Eating Enough Protein for Metabolic Health
Protein is the most important macronutrient when it comes to metabolic health. Consuming enough protein for your body is necessary to preserve muscle mass as you age. Protein is necessary to repair and build muscle tissues.
Why Eating More Might Be Helpful for Muscle Gains
While of course eating enough protein is vital for muscle health and metabolism, it’s almost more important to make sure you’re consuming enough calories on a daily basis to support your unique body’s needs.
Building muscle is an anabolic process, meaning muscle is being built and therefore requires energy to do so. It’s a common misconception that in order to speed up metabolism and get toned that people need to cut calories. Rather, it’s important to understand your energy needs and to ensure you’re giving your body enough fuel to build new muscle tissue (3).
How to Maintain a Fast Metabolism as We Age
While it’s impossible to completely avoid the natural decline in metabolism that comes along with aging, there are strategies to help keep your metabolism as active as possible. Here are some ways to help support a fast and healthy metabolism as we age:
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Stay Active
Aim to incorporate both cardio and strength training into your weekly routine to burn calories, build muscle, and support metabolic health.
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Eat Enough Protein
Include plenty of protein-rich foods like lean meats, fish, beans, and dairy to support muscle maintenance and repair. At minimum most people need 0.8 grams of protein per kilogram of body weight.
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Prioritize Sleep
Ensuring adequate, good quality sleep is vital to so many aspects of health, and when it comes to metabolism, sleep is key. Poor sleep has been associated with hormonal imbalances and increased hunger that can slow metabolism and lead to weight gain. Aim to get 7-9 hours of good quality sleep each night.
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Manage Stress
While it’s impossible to avoid all stress, as stress is a part of the human experience, it’s important to put effort into managing your stress levels. Chronic stress can increase cortisol levels which can increase fat deposition, particularly around the abdomen, and lead to a slower metabolism. Incorporate stress-reduction rituals into your routine such as meditation, yoga, and making sure you’re taking time for yourself.
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Stay Hydrated
Although hydration is not the first thing people think of when it comes to metabolism, water is actually essential for metabolic processes. Even being mildly dehydrated can reduce your metabolic rate, which is why it’s so important to drink plenty of hydrating fluids throughout the day.
Is it More Difficult to Gain Muscle With Fast Metabolism?
The speed of your metabolism does not impact your ability to build muscle. Therefore, having a fast metabolism doesn’t necessarily make it harder to build muscle.
Muscle growth relies on good nutrition, adequate protein intake, and an effective strength training routine. People with faster metabolisms may need to consume more calories on a daily basis to support muscle growth, however, this does not necessarily make it harder for them to gain muscle.
It’s best to focus on calorie-dense, nutrient-rich foods to help meet their increased energy needs and build muscle.
Key Takeaways
While metabolism naturally slows with age, there are various factors that impact metabolic rate and many actionable steps people can take to better manage their metabolic health as they age.
Factors such as muscle mass, physical activity, genetics, and hormonal changes can impact metabolism.
To ensure a healthy metabolism as you age it’s important to focus on getting adequate protein intake, engaging in regular strength-training exercise, staying adequately hydrated, and managing stress levels.
By understanding the factors that influence metabolism, everyone has the ability to take practice steps to stay healthy, energized, and metabolically strong at any age.
Also Read:
How to Gain Weight With a Fast Metabolism
