A recent study found basically no change in metabolism from the age of 20-60: https://www.bbc.com/news/health-58186710 https://www.bbc.com/news/health-58186710

A recent study found basically no change in metabolism from the age of 20-60: https://www.bbc.com/news/health-58186710 https://www.bbc.com/news/health-58186710 People usually just start packing on a few pounds a year (or more) in their 20s and it adds up.