How many times have you heard this: Watch what you eat or youll put on weight once you hit adulthood, especially during your 20s? Well, its time to put the rumours to rest because a new international study published in the Science journal found that our metabolism starts slowing down a lot later in life than we thought. Heres why its a good thing.This was one of the most thorough studies on metabolism, where over 80 researchers from 63 institutions all over the world including North America, Asia, Europe, Africa, the Middle East, and the Caribbean submitted data for analysis. The information being studied spanned over four decades from 6,500 people between the ages of eight days to 95 years.The study reported that our metabolism rate is influenced by four life stages. Infants up to the age of one have the fastest metabolism. Once theyre a year old, it declines to adult levels by the age of 20, after which it remains stable till we turn 60 years old. Then, it declines by about 20 per cent till we reach the age of 95.While researchers were expecting to see a change in metabolism when women hit their 40sdue to menopausethat just wasnt true. The contributing factors that affect metabolism can include a change in your food intake, sleep, and activity levels, as well as where you live and what you have access to.