If you’ve eaten unhealthy stuff and want to do damage control, a better idea is to eat stuff that’s high in dietary fibers. It’ll help the food to pass through your digestive system faster, and more of the counter-productive nutrients you ate will go right on out again, into the toilet. That also works for the nutrients you want to retain and put to use, though, like your protein shakes and whatnot.
With that said, yes, of course it still makes a difference. At the very least, if on top of eating the wrong stuff you also don’t work out, the damage will only be worse for it, to your body and even more to your morale.
And for your muscle development it doesn’t matter at all how much chocolate you eat, as long as the muscles have to work hard and get enough protein.
Some notes on mind-set:
It’s okay to indulge in something unhealthy sometimes. It certainly isn’t productive to feel so guilty about it that you consider your whole day wasted and curse yourself for being so stupid and spineless and why couldn’t you just etc. etc. etc. I know this problem. Self-loathing only makes it worse. You need positive reinforcement, too. And a little pride.
If you feel guilty about it, make up for it, and then forgive yourself. If you’ve indulged in tasty food against your resolutions, make up for it by working harder on your work-out, like running an extra lap or something. Try to make sure it won’t happen again, unless you’ve decided well in advance that it’s okay this time. And then forgive yourself.
As for depression, unhealthy eating and working out: in my case, I’ve found that working out can work wonders against depression. It’s a simple task, it’s not confusing, the effort it takes to succeed is purely physical. It gets your blood pumping, it makes you feel more alive than anything. And if you have what it takes to explore, push against and raise the very boundaries of what you can do with an all out effort, even if it hurts, even if you’re tired, then you’re clearly awesome enough to take on pretty much any problem. Because you don’t quit when things get difficult.
I didn’t always have that mind-set. I acquired it. Maybe you could, too.
The next time you feel depressed, you could try going for a run or doing some weightlifting. See how it makes you feel.