The problem is I think a lot of us make this a more frequent habit than we should. Maybe it's not even a meal but a snack, that over time has gotten bigger and bigger. What started out as a handful of popcorn before bed has now turned into a ham sandwhich.
Unfortunately, this does add up over time and it shows on our waist lines. My suggestion is, analyze why you are eating. Often, it from one or more issues: a) you didn't eat well enough during the day b) you've developed a habit.
Did you eat a balanced breakfast, lunch and dinner today?
Did you have an appropriate snack between meals spaced far apart?
Do you always seem to snack when your favourite shows are on?
As a guideline, a snack should be somewhere around the 100-150 calorie mark. If your snack is looking a little more substantial then that, perhaps it's hindering your weight loss.