Interestingly enough, the days I bike or do significant physical activities are the days I eat pretty healthy/not too much. Why? Because my weirdo logic goes like this:
Well, I've already exercised (since I biked in) so I don't want to "ruin" that exercise by eating pizza at lunch. And then since I have to bike home, I figure I might as well keep being healthy to not ruin my bike ride home and I cook dinner and use the leftovers for lunch the next day creating a virtuous cycle.
If I haven't exercised then it goes:
Well, shit, I didn't exercise so fuck it - having a pizza. Then, since I didn't bike in, I don't bike home, eat dinner out or eat garbage, dont' have leftovers, creating a downward spiral.
Haha, I sound like a crazy fuck now that I wrote that but that's how my simple brain computes things.
Weird but true (at least for me).