I'm a person who has vacillated between being close to normal weight and obese. I think people who don't have problems controlling their diet tend to underestimate just how hard it can be to eat at a calorie deficit or even just maintenance when you've lost a large amount of weight. When I'm at my lowest weight I literally am thinking about food constantly and my maintenance calorie intake drops to about 1500-1800 calories.
"processed" food is fine - all food is processed. The issue is with huge amounts of fast carbs coupled with high fat. It can occur even with "unprocessed" foods such ice cream.