How our metabolism changes as we age
Our metabolism changes as we age, but according to a new study, the changes only occur at specific stages of our lives and remain constant through most of our adulthood.
The researchers, from 29 countries, looked at 6400 people and found there are four distinct stages of our metabolic life.
From birth to one year old, the metabolism rises, peaking at around 50% higher than our adult level.
From 1-20, it gradually slows to our adult rate, with no spikes during puberty.
From 20-60 it is steady.
From 60 years old, it begins to decline.
The researchers measured the metabolic rate of the 6400 subjects using doubly labelled water, which is made up of heavier isotopes of the hydrogen and oxygen atoms that make up water molecules. These heavy isotopes can be tracked as they leave the body, allowing the researchers to calculate the speed of metabolic processes, adjusting for individual body size.
They were surprised to find there was no spike in metabolism either during puberty or pregnancy. Nor was there a slowdown around the time of menopause.
The research has implications for the treatment of various diseases such as cancers, and even opens up the possibility of slowing the diseases of old age through modifying the metabolism.