What do you think of when you hear the word “metabolism?” Most people probably think about how quickly or slowly their body burns calories. And while metabolism does play a role in weight control, it’s just one piece of the puzzle. In fact, your metabolism changes as you age, but not necessarily in the way you expect. To learn more, keep reading.


Metabolism is all the chemical reactions that happen in your body. It’s how cells turn what you eat and drink into energy. Some of this happens automatically. For example, when you breathe in oxygen, your body uses it to burn glucose (a type of sugar) and produce ATP (adenosine triphosphate), which is the cell’s main source of energy. Other reactions require a bit more effort, like when your muscles contract to make them move.

All of these chemical reactions add up to what we call metabolism. Metabolic function refers to the metabolic rate which is the amount of energy that a person uses in a given time period. This can be affected by many factors such as age, body weight and height. In humans, the average metabolic function is 45 calories per hour for every 100 pounds of bodyweight (90 k/h for every kg).


Aging means different things to different people, but for most of us, it eventually brings with it declines in physical and mental health. During the aging process, many changes occur. Some are welcomed, like wisdom and self-assurance; others not so much—sagging skin, weight gain and wrinkles among them. One change that shouldn’t come as a surprise is modifications in your metabolism.

The speed of your metabolic function decreases with age, which means you burn fewer calories—about 2 percent per decade after the age of 25. There are physiological changes that occur with getting older such as a reduction in lean muscle mass and a slowing of your metabolism that led to weight gain. Some blame drops in hormones such as testosterone for this unwelcome change. In fact, some research indicates that in males the less testosterone you have, the more body fat you tend to carry.[i]

What else changes with age? Your body’s ability to regulate temperature. As you get older, you may find that you perspire less or not at all when it’s hot out, and need more layers to stay warm in the wintertime. [ii]


There are many signs that your metabolism is impaired. Some common ones include:

·     Loss of muscle mass

·     Weight gain (especially around the waist)

·     Getting sick more often than you used to

·     Needing caffeine or sugar to get through the day

Loss of muscle mass:

Once you start losing muscle, your metabolic function starts to slow down. Muscle is important for many reasons. Not only does it help with everyday tasks (like walking and moving groceries into the house), it also increases your resting metabolic rate (the number of calories that remain even when you’re at rest). This means that the more muscle you have, the higher your metabolism is.

Weight gain (especially around the waist):

Weight gain is often the first sign that your metabolic function is slowing down. Getting weight around your middle can be a warning sign of diabetes, high blood pressure and other health concerns. By understanding what’s happening to your body, you can begin to make changes now that will help prevent more serious complications down the road.

Needing caffeine or sugar to get through the day:

As you age, you are less sensitive to medications and hormones that normally stimulate your heart rate, breathing and other functions. This means that you need more of these stimulants—like caffeine—to keep yourself going. It’s important to know why you’re feeling tired. If it’s related to lifestyle, you can start making changes now that will improve your chances of staying healthy as you age.

One thing that cannot be changed is our genetic code, which tells our bodies how to build and maintain cells and tissues. You are born with genes that determine everything from your eye color to your weight. Genes work with the environment you’re in and determine how your body functions, including how quickly it burns calories.

Environmental factors can affect our metabolic function too. In fact, what we eat and drink on a daily basis has a major impact on our health, metabolism and body composition.


A significant change in your metabolic function can have a big impact on your health. If the rate at which you burn calories is lower than what you’re using, you’ll gain weight. This may explain why there’s a link between lower metabolism and being overweight or obese as people age. In fact, one study found that for every 5 percent decrease in resting metabolic rate, a person’s risk of becoming obese increased by 30 percent.

While being overweight or obese puts you at greater risk for numerous health conditions, having too little body fat can have significant drawbacks as well. For example, people who are underweight may lack energy and have difficulty getting through the day. People with eating disorders such as anorexia nervosa may also experience reduced metabolic function.

Extreme changes in weight can impact your body’s ability to function normally, too. For example, if you go on a very low-calorie diet to lose weight quickly, you’ll not only burn fewer calories, but your body will also most likely burn fewer calories at rest, which can result in a slower metabolism.

For many people, one of the most stressful events they face is moving to a new location or starting a new job. One universal truth about getting older is that life changes are inevitable. If you experience significant change, try not to get overwhelmed thinking all your plans for achieving health and wellness will be disrupted.

Take a deep breath, stop, and think through your options to create a plan that will help you handle the change as smoothly as possible. The calmer and more confident you can be in dealing with changes that happen in life, the less stress you’ll feel and the more likely it is that it will have a positive impact on your health.


Your body is a complex system made up of many parts that work together harmoniously. This means that what you eat and drink, how much activity you do and other aspects of your lifestyle affect your metabolism and health. It also means that if there’s a problem with one component, it can affect others too. For example:

If you don’t drink enough water, your body will work harder to digest food and absorb nutrients. If you eat more than you need, it may store extra calories as fat instead of burning them off.

Institute for Human Optimization

We are seeing more a paradigm shift in healthcare.  At IfHO, we partner with you to become your health intelligence partner with the goal of optimizing your health. We accomplish this with our signature precision medicine approach. This may include functional, traditional, and naturopathic medicine. Our providers use a combination of therapies that are tailored to your specific needs with a health optimization goal. We believe that our Medical Team should make use of the latest scientific research to offer our patients personalized medicine, based on real data. We call this precision health and it is the future of healthcare.

Our focus is not only looking at the root cause, but also to measure, quantify and optimize the patient’s personal health. We take a preventative approach, personalized, and precise approach in helping our patients control their risk factors early on in order to avoid chronic illness down the road. Our team of medical providers use a comprehensive approach with every patient that comes into our office, looking at all aspects of health including lifestyle, environment and genetics. There is no generic one size fit all protocols. No two patients receive the same treatment plan since we work with each individual to create a personalized plan. We empower our patients with the right tools and information, so they can take control of their own health. This is the future of longevity!

Disclaimer: The content is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Additionally, the information provided in this blog, including but not limited to, text, graphics, images, and other material contained on this website, or in any linked materials, including but not limited to, text, graphics, images are not intended and should not be construed as medical advice and are for informational purposes only and should not be construed as medical advice. Always seek the advice of your physician or another qualified health provider with any questions you may have regarding a medical condition. Before taking any medications, over-the-counter drugs, supplements or herbs, consult a physician for a thorough evaluation. Always seek the advice of your physician or other qualified health care provider with any questions you may have regarding a medical condition or treatment and before undertaking a new health care regimen, and never disregard professional medical advice or delay in seeking it because of something you have read on this or any website.

[i] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4154787/

[ii] https://pubmed.ncbi.nlm.nih.gov/22085834/