1. People in my town eat fish a lot, but we eat only fish heads.

Question

2. People in my town eat fish a lot, but they eat only fish heads.

(Which one do we have to use, 'we' or 'they'? Are they the same? Is there any difference in meaing?)

Answer 1

If, in the other sentences around this one, it's clear you are telling about yourself and others (so the use of "we" makes sense), then #1 is fine.

If you are clearly telling about what other people do, not including yourself, then #2 is correct.