The human body is complex and ultimately poorly understood. These studies typically focus on short-term hunger cues which aren't necessarily indicative of why someone can happily eat 1 meal a day and someone else feels compelled to eat mcdonalds 3x per day.

Anecdotally, If I have a deficiency I'll keep snacking/eating until I've found something that satisfies the deficiency or I'm completely full. Eating to fullness 3x per day or more is a great way to gain a ton of weight.