I got out of severe depression by trying and keeping at it to do these things I didn't even believe could help me anymore. Surprise, they did. Yes it took long and was hard. But it is possible to do even a little bit.

The part telling me I can't do it and saying I shouldn't even try cus I won't do it anyways, that is part of the depression too. It is self sustaining.

In my mind the trick that worked was: if everything is shit no matter what, if I hate every second anyways no matter what I do, if nothing will change how miserable I am, then taking a short walk won't change anything for the worse either, not to any significant degree anyways.

That way bit by bit my absolute apathy tricked itself into doing things because it didn't matter either way. And slowly shit got tiny bits better.

The advice works, but only if you have the strength to do it and not everyone does.

Realize that some of these aren't just decisions you have to get right every day (like walking every day), they're decisions you have to get right 86400 times a day. If you crave junk food, you don't just decide "I'll stop eating it", you have to make that decision every second of every day, because if you slip once, you're fucked. It gets easier, sure, but the first days/weeks are brutal.