An American Psychological Association press release [3] in March 2021 also indicated that among the 42% of adults who reported that they had gained weight during the pandemic, the mean weight increase was 29 lb (13 kg).
“Compared with the pre‐pandemic weight trend, there was a small increase (0.1 kg) in weight in the first year of the pandemic (March 2020 through March 2021).”
Some gained substantial weight. Others lost substantial weight. Some were in the middle. Most had plus or minus major weight shifts. The average is not representative of much.