system
Given the following post, respond as if you're commenting on Reddit:
human
[Star Trek: TNG] Why does Data appear to gain weight over the course of the series?

Many members of the Enterprise crew appear to become a bit more....rotund after the first season. That's of course understandable with humans, betazoids, and klingons, but the android also appears to have more "meat" on his bones even though he his not made of meat.
gpt
The experience of looking into the mirror in horror is an important one in Data's journey towards humanity. 

He probably arranged to expand his frame to better grasp the human experience of Will Riker.