Four Reasons Our Metabolism Changes with Age

Four Reasons Our Metabolism Changes with Age

Aging Metabolism

By Gary Pepper, M.D., and Sam Jeans MSc

It’s tempting to think that our bodies simply ‘slow down’ as we age, which makes it harder to keep weight off, but a study of 6,600 people aged between one week old to 95-years-old revealed that it’s not as simple as one might assume.

In our prior post, we defined what metabolism really is (a mixture of at least 3 different processes), so we can now move on to discussing how these processes change as we age.

A 2021 study, published in Science, found that our total daily energy expenditure is 50% faster in our first year of life than during adulthood. After our first birthday, our daily energy expenditure begins to taper off by some 3% each year until around the age of 20.

But here’s the surprise; instead of our total daily expenditure slowing gradually from say, the age of 30 onwards, it tends to remain very stable until the age of 50 or 60. After then, it decreases only slightly, by around 0.7% per year.

“Some people think of their teens and 20s as the age when their calorie-burning potential hits its peak…But the study shows that, pound for pound, infants have the highest metabolic rates of all.” – Dr. Katzmarzyk, Professor and Associate Executive Director for Population and Public Health Sciences at the Pennington Biomedical Research Center.

In essence, what this study shows is that the metabolism – and total energy expenditure – slows over time because of a mixture of factors, and not just because of age only. In other words, many people gain weight as they age for reasons other than what is often simply described as “the body slows down as you age”.

If you’re struggling more with your weight as you age, there are probably a few different things going on.

Problems and Solutions for Age-Related Weight Gain

1: Your Diet Has Changed

Diets can change in either direction with age, they might vastly improve as we realize the benefits of a healthy diet, or they might slip deeper and deeper into bad habits and indulgence!

What we do know is that a high-fat, low-protein diet lowers the thermic effect of food, which means that more excess calories end up deposited as fat.

A 2016 study from Purdue University found that a high-protein diet can boost the metabolism, boosting energy expenditure by around 100 calories per day. That’s 100 calories you’re losing for free, without moving, simply by eating high protein foods. For how long the increase in calorie burning by high protein diet lasts, is not clear, however.

Grabbing a shelf full of protein supplements in your 50s, 60s, or 70s is probably not required.

The following is a list of natural high-protein foodstuffs to consider:

  • Nuts
  • Beans, peas, and legumes
  • Seeds
  • Eggs
  • Soy
  • Unprocessed dairy
  • Oats and grains
  • Dark leafy vegetables

2: You’re Moving Less

Next up, it’s all too easy to start moving less with age. Rather than low-level exercise, it’s usually the more vigorous activities that start getting neglected with age.

Exercise demands remain quite consistent throughout life, and it’s generally now recommended that older adults up to the age of around 50 to 60 commit to a similar exercise regime as those aged much younger. The older we become however, limitations on exercise duration and intensity are imposed by illness and degenerative conditions such as arthritis, heart and lung disease and whatever injuries have occurred over the years.

Web MD recommends a considerable 150 minutes of moderate cardio spread over 3 days or more, which is what the CDC recommends for all adults who are medically able.

A strong body of research has also found that more rigorous exercise like high-intensity interval training can protect seniors from an array of diseases whilst bolstering their metabolism. It is strongly advised, particularly in older individuals, that before stepping up your exercise regime to always consult a physician prior to starting.

3: You’ve Lost Muscle Mass

Muscle loss (sarcopenia) reduces BMR whilst simultaneously reducing the number of calories burnt during exercise. Harvard Health cites that muscle loss can hit 3% to 5% per year after the age of 30. A higher percentage of lean muscle tissue boosts the level of calories burnt during exercise and at rest, so fighting against muscle loss is a potent way to maintain a steady metabolism.

It’s possible to fight against muscle loss by engaging in strength and resistance training in addition to your standard exercise regime. Follow a strength or resistance training plan approved by a professional, aimed at your age group and skill level and always take things slowly at the start.

4: Your Hormone Levels Have Changed

The hormone levels of both men and women progressively change with age.

Whilst men obviously do not experience anything like the level of hormone change that comes with female menopause, they may still experience somewhat of a “male menopause” which involves the loss of testosterone often beginning during the 50’s. Obesity in men is also associated with lower testosterone levels, creating a vicious cycle of increasing obesity causing lower testosterone which then inhibits the ability to lose weight, and so on.

Medical News Today primarily recommends lifestyle changes to support hormone levels, including increasing exercise and decreasing consumption of processed and fatty foods. Limiting alcohol consumption is also recommended not only to reduce caloric intake but alcohol may also suppress male hormone (testosterone) production.

Some herbs and supplements are also suggested to support metabolic hormones – Ginseng, Maca, and Ashwagandha are amongst those that show the most promising preliminary evidence, though large-scale studies are still lacking.

Summary: How Getting Older Affects Your Metabolism

Age does affect the metabolism, but it’s not as simple as your body just “slowing down” as you get older – and we are not powerless to stop it!

We have greater control over our metabolism than generally assumed and making just a handful of small changes might be all it takes to beat the “middle-aged spread”.

Considering all 3 components of the metabolism – BMR, TEF, and TEE – helps target strategies aimed at improving each, such as switching to a high-protein diet to increase calorie burning during eating, increasing exercise, and also supporting hormone function, and increasing lean muscle mass to boost BMR.

A combined, holistic approach provides a much better outcome than focusing on just one part of the metabolism in isolation of the others.

Disclaimer: This and all articles at are for educational purposes only and are not intended as medical advice or treatment. By choosing to view this article you agree to the Terms of Use of Metabolink, Inc which can be found at


Diabetes is on the Rise in Childhood and Adolescence

Diabetes is on the Rise in Childhood and Adolescence

When kids come up against that common eat right and exercise refrain, they may be all too apt to brush health concerns aside as something only adults have to consider. Heart issues, kidney problems, and especially type 2 diabetes — those words have an “adults only” connotation.

However, the potential to develop type 2 diabetes in adulthood or even earlier comes with a clear link to overweight and obesity at young ages. With it comes an elevated risk for associated health complications, too. While research has indicated some alarming trends, there are also promising findings that hint at the opportunity for individuals to make sustainable change.

Sustainable change isn’t about simple calorie counting — where those calories come from can have just as big an impact on overall health. Families can have fun experimenting with recipes and food choices to give kids the power to view nutrition as a holistic part of their everyday routine.

Prediabetes and Type 2 Diabetes Cases on the Rise

Type 2 diabetes, a disease once known as adult-onset diabetes, has started to impact young people more and more. Recent research paints an increasingly unsettling picture.

A 2019 study published in JAMA Pediatrics found nearly 1 in 5 adolescents are already living with prediabetes, with the percentage of kids between the ages of 12 and 18 with prediabetes higher in those with obesity. Prediabetes, a health condition characterized by higher-than-normal blood sugar levels, can lead to type 2 diabetes and may offer an early window into what’s to come.

But it’s not just prediabetes acting as a glimpse of a problematic but distant future. Researchers are also seeing a shift in type 2 diabetes prevalence in youths. A CDC report from 2020, for example, found the rate of new type 2 diabetes cases for young people under 20 years old in the United States increasing 4.8% per year.

Obesity and Overweight As Diabetes Risk Factors

Though not the only factors, obesity and overweight are helping to spur the rise in type 2 diabetes among children and adolescents. A 2005 review in the journal Pediatrics examined the ongoing trend. The review noted that having overweight or obesity actually serves as the biggest risk factor for youth to develop type 2 diabetes, highlighting weight loss and prevention of weight gain as strategies to combat eventual disease development.

Indeed, as the number of overweight and obese children has increased, so too has the number of type 2 diabetes cases in younger people. Early diabetes development means affected young people may start experiencing complications associated with diabetes at an earlier age as well.

What Happens When Young People Develop Type 2 Diabetes?

Younger diabetes diagnosis and the potential for complications at an earlier age speak to the heart of the looming public health problem.

An earlier type 2 diabetes diagnosis goes hand in hand with greater risk. Earlier development means longer exposure to the disease, and young people who develop type 2 diabetes may need treatments like insulin earlier in life. Evidence also exists hinting at early-onset type 2 diabetes as a more aggressive form of the disease.

Children and adolescents with type 2 diabetes face health issues similar to their adult counterparts, but may experience these complications starting at an earlier age, according to the review in Pediatrics. Cardiovascular complications, kidney issues, health problems that threaten the limbs — the list goes on. Even if the diabetes diagnosis doesn’t come during childhood or adolescence, kids who are overweight or obese are still at a higher risk to develop the disease eventually.

Research Highlights Promising Opportunities for Change

The news isn’t all bad, though. Consider a study by Bjerregaard et al published in the New England Journal of Medicine in 2018.

Acknowledging that children who have overweight are at an increased risk for type 2 diabetes in adulthood, the study looked at Danish men who had their weights and heights measured at 7 and 13 years old and then again in early adulthood, defined in the study as between the ages of 17 and 26. The researchers sought to determine if children who were overweight at a young age would continue to have an increased risk of developing adult type 2 diabetes if they no longer were overweight at puberty or later.

The study uncovered promising statistics. Men who maintained a normal weight in early adulthood after losing weight between 7 and 13 years old had a risk of type 2 diabetes similar to men who had normal weight at all ages. While men who lost weight between 13 years old and early adulthood had a higher diabetes risk than men who had never been overweight, the risk was still lower than in men who were overweight at all ages included in the study.

Reversing the Trend Starts At Home

Focusing on being overweight in puberty as an important factor ultimately increasing the risk of developing type 2 diabetes later in life, the New England Journal of Medicine study indicates just how important learning healthy habits at a young age can be.

Family factors — such as food available at home and food preferences of family members — can influence what kids eat, and these factors have been associated with rising obesity cases. On the flip side, if kids learn about healthy eating, positive nutritional choices, and exercising at home, those lessons can carry over into choices kids make beyond the walls of their home.

Being overweight or obese aren’t the only risk factors for developing type 2 diabetes, and a holistic, empowering approach to any weight loss recommendations for kids is certainly a must. Still, the clear link means it’s something kids and the adults in their lives should pay attention to. Type 2 diabetes comes with the potential for complications in childhood and beyond — and the risks only increase with earlier disease onset. Yes, the stakes are high, but research indicates the lasting, positive impact that changes to nutrition and activity can have

Share Childhood Food Memories to Help Combat Childhood Obesity

Share Childhood Food Memories to Help Combat Childhood Obesity

Without question the eating habits we develop as kids helps determine if we are going to be a heavy adult. Almost a third of children and adolescents in the US are classified as either overweight or obese (JAMA 2014; Ogden, CL).

Many of these children become obese adults. If a child’s parents are heavy their risk is doubled for becoming an overweight adult. is involved in finding ways to reduce childhood obesity.

The first step is to raise awareness of the dangers of childhood obesity and how crucial it is for young people to learn how to eat properly. For this reason we are kicking off a Facebook and Instagram campaign called “ Food Flashback”.

Food Flashback means sharing memories of how each of us first learned about food and nutrition. Most of us have some vivid recollections of family meals, watching our parents cooking, favorite foods and snacks as a child.

Can a Blood Test Identify Those Who Need T3 for Proper Treatment of Hypothyroidism?

Can a Blood Test Identify Those Who Need T3 for Proper Treatment of Hypothyroidism?

Dr. Gary Pepper and Dr. Paul Aoun discuss recent findings about thyroid hormone treatment at the 15th International Thyroid Congress

Dr. Gary Pepper and Dr. Paul Aoun discuss recent findings about thyroid hormone treatment at the 15th International Thyroid Congress

According to experts, 10 to 20% of hypothyroid individuals fail to respond completely to T4-only (levothyroxine, Synthroid) treatment. Dr. Anthony Bianco, the president of the American Thyroid Association, and his associates believe this is due to genetic variations in the way thyroid hormone is converted in the body from T4 into T3. T3 is the much more potent form of thyroid hormone and unless the cells of the body receive enough T3, normal function cannot be achieved and symptoms of low thyroid such as fatigue, mental fogginess, constipation, muscle aches etc, persist. Based on the research conducted by Dr. Bianco and colleagues it is thought that in those with the genetic trait making T4 treatment ineffective, blood tests would show low T3 levels. (more…)

Tara Struggles with Persistent Symptoms of Hypothyroidism and Her Medical Care

Sad received this message from one of our readers. Her story seems typical of the sort of dilemma so many people face today. The best advice usually comes from others who face the same problem. It would be helpful to hear what others would do in her situation.

Tara’s message: “I was diagnosed with Grave’s Disease in 2009, I had RAI in 2011, after my daughter turned 3 months. Being pregnant with Severe Grave’s was the scariest thing in my life at the time. I gained weight prior to my pregnancy, during, and after RAI. My family doctor told me no matter how much you ate while severe Hyperthyroid you should have been anorexic, so something else is wrong. ” (more…)

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