How long should you wait to go to bed after eating so you don't gain weight?

I have read an article that an experiment made with 96 people in UK during one year showed that half of the group that waited no less than 2 hours before going to bed lost an average of 6 kilos (13 pounds). I have been trying to wait at least 3 hours, for what I not always suceed due to my lack of discipline, but I reduced my weight from 106kg (233lb) to 89 kg (196lb) over the past 6 years. I don´t know how much is a coincidence or how much was effective due to the change of habit. But fact is that I lost a considerable weight and for sure I have much better sleep, particularly when I wait long after alchoolic drinking.