Over time, studies have shown that metabolic rate (how fast we burn calories) starts to slow down by 2 to 3 percent each decade, beginning in our 20s. It becomes more noticeable between ages 40 and 60.
Your metabolic rate does change during your early life, but it plateaus between the ages of 20 and 60, and only decreases by around 1% per year after that. Your total daily energy expenditure also depends on your weight.
Your metabolic rate peaks in your early 20s, according to Women's Health Magazine. At this age, you tend to have a higher muscle mass and have a fair amount of physical activity built into your day. As early as age 30, however, men and women begin noticing a dip in their ability to lose weight.
Well, not until we're in our 60s, anyway. Researchers found that metabolism peaks around age 1, when babies burn calories 50 percent faster than adults, and then gradually declines roughly 3 percent a year until around age 20.
As we age, our metabolism slows and the rate at which we break down food decreases by 10 percent each decade after age 20. Metabolism is the amount of energy (calories) your body uses to maintain itself.
Study shows that younger people and women are more likely to put on extra pounds. A study that examined the long-term weight gain of more than 13,800 U.S. adults found that on average, people gained about 17 pounds between their twenties and thirties.
Aerobic activity can help control weight and can lower your risk of heart disease, diabetes, and many other conditions. Muscle-strengthening exercises are important for the same reasons but will also boost your metabolism.
The rate of living theory postulates that the faster an organism's metabolism, the shorter its lifespan.
Eating too few calories can cause a major decrease in metabolism. Although a calorie deficit is needed for weight loss, it can be counterproductive for your calorie intake to drop too low.
For example, aerobic capacity declined 3% to 6% each decade in the 20s and 30s, but after age 70 the rate of decline accelerated to more than 20% per decade. The study also showed that after age 40, men's fitness levels declined at a faster rate than women, regardless of their level of physical activity.
If your metabolic age is lower than your actual age, it means your body is in good health. Some adults can have the metabolic age of a 15-year-old or lower, which means their body is top of the class at burning calories.
Metabolism is partly genetic and largely outside of one's control. Changing it is a matter of considerable debate. Some people are just lucky. They inherited genes that promote a faster metabolism and can eat more than others without gaining weight.
Those extra pounds were packed on in early adulthood: The average American gained about 17.6 pounds from their mid-20s to mid-30s, the study found. Meanwhile, the average person gained about 14.3 pounds between their 30s and 40s, 9.5 pounds between their 40s and 50s, and 4.6 pounds between their 50s and 60s.
The rate of increase starts to slow in the 30s and 40s, and plateaus in your 50s. After that, the average weight falls. The kids are out of the house and your career is hopefully in order, freeing up more time to take care of yourself.
It simply takes time. Another common reason why people report not losing weight despite reducing their calories is that they don't give it enough time. Our bodies will do their utmost to hold on to our fat reserves and you often have to be in a calorie deficit for a while before you will see any meaningful weight loss.
You've gained muscle.
And here's an often overlooked fact: Muscle tissue is more dense than fat tissue. So as you gain more muscle and lose fat, you change your overall body composition, which can result in a higher weight, but a smaller figure and better health.
Hormones
A shift in your hormones can put the brakes on your body's energy use. That can make you tired. Some conditions, like an underactive or overactive thyroid and diabetes, are hormonal diseases that affect your metabolism. Stress also releases hormones that can trigger a slow-down.
Being less active, losing muscle mass and the aging of your internal components all contribute to a sluggish metabolism. Fortunately, there are plenty of ways to fight aging from slowing down your metabolism.