Fast food doesn’t necessarily mean high calorie either. Almost all fast food places have meals for under 600 calories, yes even McDonald’s.
When I quit smoking, the hardest days were the stressful ones. It didn't matter that just the previous day I swore I would never have a cigarette again. I'm sitting in my car, I'm down on myself, and I would give anything in that moment for just a hit of release.
We're not robots. We're not efficient, we're not productive, we just kind of... do. Our systems don't make sense, they're not linear, they're not necessarily predictable. How the mind feels isn't the kind of thing we can just land a dart on.
A better way to be thinking about this is at what point will you stop gaining weight? If you are someone who burns 2000 calorie a day but eats 2170 calories a day, you will be gaining 170 calories on that first day. But then you will add some fat, and you will burn 2001 calories, and only gain 169 calories the next day. Eventually you will reach equilibrium where you burn 2170 calories. But fat isn't like muscle, it's very efficient because that is it's main purpose - it just sits there. So it actually takes a lot to reach that new equilibrium.
The rule of thumb is 100 calories surplus will lead to a long run gain of about 15 pounds. So the 177 calorie average would end up yielding about 25 pounds of fat above what they should have.
Then the next question is if you will ever reach equilibrium, or if when you start burning 2001 calories, you start eating 2171 calories...