For starters, there is no real reason t fear eating at night. Your body will digest food the same way regardless of time. The association between time and weight gain is another product of CW; a mere correlation really. Why do sme people gain weight from night snacking? Two main reasons.
1. They eat crap at night (ice cream, chips, etc). But why are they hungry in the first place?
2. They eat crap during the day. All the cereal, bread, and sugar screws up tye metabolism and digestion while booming ajd busting insulin levels causing hunger spikes.
The lesson: eating at night leads to weight gain if you are eating more than you need in combination of what you ate during the day. If yiu don't spike your insulin with crap food, you will not be as hungry. If yiu are genuinely hungry, regardless of time, eat primal food until you are satisfied. Eating at night does not cause weight gain, it just does not maoe evolutionary sense.