Another study, published last year in the journal Health Psychology, shows how mind-set can affect an individual's appetite and production of a gut peptide called ghrelin (GREL-in), which is involved in the feeling of satisfaction after eating. Ghrelin levels are supposed to rise when the body needs food and fall proportionally as calories are consumed, telling the brain the body is no longer hungry and doesn't need to search out more food.
Yet the data show ghrelin levels depended on how many calories participants were told they were consuming, not how many they actually consumed. When told a milkshake they were about to drink had 620 calories and was "indulgent," the participants' ghrelin levels fell more—the brain perceived it was satisfied more quickly—than when they were told the shake had 120 calories and was "sensible.
The results may offer a physiological explanation of why eating diet foods can feel so unsatisfying, says Ms. Crum, first author on the study. "That mind-set of dieting is telling the body you're not getting enough."So there you have it. This study suggests that if you think you are getting a lot of food, then it can instruct your hormones to pipe down and let you feel full. If your brain thinks you are getting gipped, then it asks your hormones to scream for more. There is clearly a bizarre circular logic being used by our neurological systems, but what I suppose it is what it is.
One example of how we can use this curious effect to our benefit is in the use of low energy density foods. These are foods that have relatively few calories per cubic meter, often filled with water, air, fiber, etc. It goes back to one of my personal rules of eating: bulk up your food. If I go back to my staple breakfast:
- Regular oatmeal with blueberries and sliced banana
- 0 fat Greek yogurt with grapes with a little Fiber One
|Big food indeed...|