It’s mentioned time and time again: It’s normal to gain weight with age because of metabolism changes. Some blame their increasing age for excess body weight, even when their diet hasn’t changed drastically. But a new enlightening study shows that what we thought we knew about how age impacts metabolism may be all wrong.
A paper published in Science is one for the textbooks, as it brought to light a common misconception in the health and wellness space. It shows that metabolism holds steady from ages 20–60 and then only slightly declines after that. So we can’t speed up metabolism after decades thinking we could?
What does this mean for the middle-aged adults out there that can’t explain their weight gain? Without your metabolism to blame, it’s time to look at other dietary and lifestyle factors.
What Is Metabolism?
Metabolism is a term for the chemicals reactions that take place in every human (and living organism) every day to stay alive. It’s the process of turning calories into usable energy.
This energy (coming from calories) is needed for a range of body functions, including immune function, fertility and healthy sex drive, lean muscle mass, brain health and longevity. People tend to think that metabolism is solely linked to weight and our ability to use calories, but it’s our brains that are the biggest benefiters of a strong metabolic rate because it depends significantly on energy to function properly.
Your basal metabolic rate (BMR) is essentially the number of calories you burn at rest each day and a BMR calculator is used to measure this rate, although it’s not an exact science. Until now, it was considered common knowledge that a person’s metabolic rate decreased in adulthood and that gender played a role in a person’s of energy conversion. But this latest study suggests that our old way of thinking isn’t the whole truth.
Landmark Study (We Got It All Wrong!)
An August, 2021 study published in Science unveiled findings that negate a major misconception about metabolism changes with age. Using data from almost 6,500 people, with ages ranging from 8 days to 95 years, researchers found that total daily energy expenditure remains stable in adulthood, even during pregnancy. The study has over 80 co-authors and includes data from six labs that’s been collected over the last 40 years.
The study indicates that there are four phases of metabolic rates that humans go through from birth to old age. The most shocking finding was that metabolism didn’t change for adults age 20 to age 60, negating the concept that metabolism slows down with age.
To measure metabolism, researchers used a method called “doubly labeled water,” which is considered the gold standard in this area of research. It involves measuring burned calories by tracking the amount of carbon dioxide that a person exhales while engaging in daily activities. A person’s weight, height and percentage of body fat was taken into account when analyzing fundamental metabolic rates for certain age groups.
Once researchers controlled for differences in body and muscle size, data also suggests that there is no difference in metabolism rates for men and women within the same age group. This idea also negates a common misconception, that women have slower metabolism rates than men and are more prone to weight gain.
Four Phases of Metabolic Rates
Researchers from this latest study found that there are four distinct phases, or stages, of metabolism that every human will go through from birth to old age.
The four phases of metabolic rates, according to this latest and expansive study, includes:
- Infancy to age 1: Highest metabolic rates, with peak calorie burning that continues to accelerate until it’s 50 percent above the adult rate.
- Ages 1–20: Metabolism grows slowly by about 3 percent per year.
- Ages 20–60: Metabolism holds steady among both men and women, even during pregnancy.
- Age 60 and older: Metabolic rate declines by about 0.7 percent per year.
Although there are individuals who have higher or lower metabolic rates than what’s average for that age group, most people follow a general pattern when it comes to declining metabolic rates, and researchers highlight that this depends on age, not weight.
While this study indicates that metabolic rates don’t decline with age the way we thought they did, what about people having different metabolic types?
There’s a theory that every person can fit into one metabolic type, or are at least be dominant in one type. Researchers from this latest study do note that some adults have higher or lower than average metabolic rates, but they still follow the same trajectory in terms of rate declines with age. So yes, some adults may have a slower metabolic rate while others have a faster one, and that can affect weight maintenance.
The types of metabolism that are often discussed include:
- Ectomorph: People with a faster metabolism and smaller bone structure that may have trouble gaining weight and can handle consuming more carbohydrates.
- Endomorph: People with a slower metabolism that have more body fat who tend to carry weight in their hips and stomach, and are more prone to insulin resistance.
- Mesomorph: People who are more muscle-dominant and have what’s considered a medium frame, being somewhere in the middle of faster and slower metabolic rates.
No More Excuses! Get Moving :)
Now that you can’t use age as an excuse, it’s time to focus on your dietary and lifestyle choices, especially when it comes to physical activity. The concept of increasing your metabolism, in light of these recent findings, is in question. But what we do know for sure is that your body weight very much depends on the foods you eat and way you move (or don’t move) your body.
Here are some things you can do to support weight loss well into adulthood:
1. Move Your Body
Now that you know your metabolic rate isn’t changing much from when you’re in your 20s to 60s, think about what else changes in your life that can lead to weight gain. Chances are that you become more sedentary over time.
To prevent weight gain, make sure you’re getting daily physical activity. Daily movement, which includes walks and runs outdoors, yoga, pilates, swimming, biking, weight lifting and HIIT (High Intensity Interval Training) workouts will help you to maintain healthy metabolic function and use consumed calories for energy.
Weight lifting and HIIT workouts even work to burn calories when your workout is over — this is known as the “afterburn effect” — and it can help you to maintain a healthy weight.
2. Get Enough (of the Right) Calories
If you’ve tried dieting and calorie restricting before, you probably know that it can leave you feeling weak and moody. Your body needs calories to use as energy so that every body system can work properly, but not every calorie is equal when it comes to your health.
Focus on nourishing your body with nutrient-dense, metabolism boosting, anti-inflammatory foods, like leafy greens, berries, wild salmon, organic chicken, grass-fed beef, bone broth, garlic, nuts and seeds, broccoli, celery, legumes and green tea.
If you’re eating high-calorie foods that are low in nutrients, protein and fiber, you’ll be reaching for another snack again soon and your body won’t feel nourished. This can lead to excessive calorie intake and weight gain.
3. Get Enough Rest
Your body needs a chance to rebound every night, so make sure that you’re getting at least seven hours of sleep per night. Stick to a healthy PM routine that allows your mind and body to slow down so that it can settle in for a night of restful sleep.
What happens when you don’t get enough sleep? You experience more sugar and carb cravings, deal with brain fog and fatigue, and promote inflammation that keeps the cycle going. Getting enough rest is one of the most important factors for maintaining a healthy weight and mindset.