Losing weight

-gloms onto this thread-
one thing i've found helpful re:exercise to remember is that exercise is not actually helpful for losing weight much, but it can be helpful for lots of other things! the great news about that is that in order to get almost all the benefits of exercise, all you need is half an hour of brisk walking 5 days per week (source: Healthcare Triage).

I'm also just starting to try and lose weight (at 168 pounds, 5'3", which is up 20-25 pounds from what my normal was just two years ago, i'm just looking to lose those 20ish pounds, but, yeah.)
I'm worried part of it might be my meds- I started in Trintellix, which isn't supposed to lead to weight gain from what I heard, but is a serotonin-affecting antidepressant, and I think I gained 15 pounds the last 4 months or so, and i started the meds 4 months ago. any specific advice about losing weight if that's the case?