Probably because satiety isn't a constant thing...our bodies adapt. As an American, whenever I spend time in Europe or Asia, I spend the first week feeling hung

Probably because satiety isn't a constant thing...our bodies adapt. As an American, whenever I spend time in Europe or Asia, I spend the first week feeling hungry. But after that, I adapt and I'm fine. And when I get back to the States, I spend the next month making two meals out of every restaurant portion I buy until my body eventually adapts back. In America, we stuff ourselves without realizing we're doing so.