Comment by aldarion

From what I have gathered (through research and by using myself as a guinea pig), there are two things about highly processed food that promote overeating: 1) high carbohydrate content 2) lack of nutrients

High carbohydrate content causes sugar spikes, which leads to insulin spikes, and insulin spikes both a) cause hunger and b) promote storage of energy in the form of body fat: https://pubmed.ncbi.nlm.nih.gov/3894001/

Second issue is as I said lack of nutrients. Your body needs nutrients, and will force you to eat until nutritional requirements had been satisfied. Since processed foods have very few nutrients, your organism compensates by increasing dietary intake... which means increasing caloric intake.