I try to eat a balanced diet. I eat chicken one day, fish, red meat.....pork every other week....... I don't count calories but I eat until I am satisfied, not until I am 'stuffed'. Perhaps I should though. I have to agree with your comments about Nutella. That stuff is addictive.
From what I understand, if you try to starve yourself during a diet, your body shuts down and you don't lose weight as fast as you would if you monitored your diet and exercised more. But, I don't understand how you could gain weight, unless they are either drinking excessive amounts of water to keep their stomachs full or cheating on their fasting. I don't know...
I think that there is a misunderstanding here. Muslims are allowed to eat during Ramadan before sunrise and after sunset. So they get up extra early and eat a large breakfast. And often eat large meals, including sweet delicacies, after sunset. Resulting in that they eat more calories per day than during other months of the year.