Your bacon excursion is perfectly compatible with calories in calories out (you burned some of the calories, others took a different exit).
The mystery would be if you gained weight over a long period of time while consuming food at a calorie deficit. People do make this argument against calorie counting...
The fundamental lesson of calories in calories out is that someone who wishes to lose weight should seek to reduce their calorie intake to a level where it happens. It probably isn't all that useful a lesson, estimating calories consumed is hard, as is reducing them.
The mystery would be if you gained weight over a long period of time while consuming food at a calorie deficit. People do make this argument against calorie counting...
The fundamental lesson of calories in calories out is that someone who wishes to lose weight should seek to reduce their calorie intake to a level where it happens. It probably isn't all that useful a lesson, estimating calories consumed is hard, as is reducing them.