In reality, the milkshake was somewhere in the middle: 380 calories. And before you get all prickly over me talking about calories, I promise it’s worth it. When the participants drank the milkshake that they thought was 640 calories, their ghrelin levels dropped. They weren’t hungry anymore. But when the participants drank the milkshake that they thought was only 140 calories . . . their ghrelin levels didn’t drop. The hormone levels stayed high, and they stayed hungry, and their metabolism stayed slow, even though they were drinking the same milkshake that the other people were.
