A new study recently suggested that an individual's metabolism, the rate at which calories are burned, peaks much earlier and begins its unavoidable decline later than thought.
According to News-Medical.Net, four researchers at Pennington Biomedical were part of an international team of scientists who examined the average calories burned by over 6,600 individuals as they went about their everyday lives.
The ages of the participants ranged from one week to 95 years old, and they lived in more than 25 countries worldwide. The other scientists at Pennington Biomedical included Associate Executive Director for Population and Public Health Peter Katzmarzyk, Ph.D.; Ingestive Behavior Laboratory Professor and Director Corby Martin, Ph.D.; and Clinical Science Associate Executive Director Eric Ravussin, Ph.D.
Most past extensive studies measured the amount of energy the body is using for basic essential functions like breathing, digesting, and pumping blood, the calories one needs just have to be alive.
The basic functions though account for only 50 percent of 70 percent of the calories burned every day. More so, they don't comprise the energy spent when doing all other things like washing the dishes, sweating it out at the gym, or walking the dog, among others.
'Doubly Labeled Water' Approach
To come up with the total amount of energy spent, the study authors applied an approach known as the "doubly labeled water," as explained on the International Atomic Energy Agency site.
This is a type of urine test that involves having individuals drink water in which the oxygen and hydrogen in water molecules have been substituted with heavy forms that were naturally occurring. Then, this approach measures how fast these forms are flushed out.
Authors of the study, Daily energy expenditure through the human life course, published in Science, have used the said method, considered the so-called "gold standard" for the measurement of everyday energy spent during everyday life outside of the laboratory, to measure energy exerted in humans since the 1980s.
Nonetheless, past studies were limited in both size and scope because of the cost. To get around such limitations, numerous laboratories shared their information in one database, to find out if they could tease out truths concealed or only hinted at past research.
Surprising Revelations on Metabolism at Its Peak and Decline
In a similar report, Medical Xpress said, pooling and evaluating energy spent throughout a whole lifespan unveiled some surprises. According to Dr. Katzmarzyk, some people think of their teenage years and 20s as their peak in terms of metabolism rate. However, this study found that "pound for pound," infants got the highest metabolic rates of all.
The researchers said that's not only because babies are just tripling their birth weight during their first year. Dr. Martin explained the babies grow fast, which accounts for much of the impact.
Nonetheless, after one controls for such, their energy expenditures are included to be higher compared to what he would expect for his body size.
The explosive metabolism of an infant may help explain the reason children who are not getting adequate food to eat during their developmental stage, are less possible to survive and grow up as healthy adults.
Findings of the study also suggest that other factors are lying behind what's considered as the "middle-age spread."
In connection to this, the data gathered also suggest that metabolisms do not really drop again until after 60 years of age. Their slowdown is gradual at only 0.7 percent each year. However, an individual, in his 90s, requires 26 percent lesser calories every day, compared to a person in his midlife.
Related information about metabolism is shown on Stated Clearly's YouTube video below:
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