physiology of hunger hormone changed by how we FEEL about the food
I could also title this post, "my new favorite study." Why? Because it is a hormonal, measurable, lab-value kind-of-thing (that should intrigue some doubters) that contributes to our understanding of why diets, no– not just diets– but "sensible" eating and likely even grudging "moderation" doesn't work. When I talk to folks and tell them that in a study of teens, even "healthy" weight maintenance or weight loss tactics such as pushing more fruits and veggies, moderation, watching what we eat etc. resulted in heavier teens with more disordered behaviors, I often get asked, "but why?" Moderation, you see, seems so, well, moderate, but moderation to most people around food means eating less than they want in terms of quantity or perceived enjoyment.Why? Because when we feel "sensible," or deprived, this study shows that we may feel less satisfied, and that an actual hormone reflects levels associated with hunger. "Sensible" mindset= levels associated with hunger. Let me clarify.The goal of the study: "To test whether physiological satiation as measured by the gut peptide ghrelin may vary depending on the mindset in which one approaches consumption of food." ( The effect of ghrelin is "to produce the sensation of hunger and motivate consumption.")The findings: "The mindset of indulgence produced a dramatically steeper decline in ghrelin after consuming the shake, whereas the mindset of sensibility produced a relatively flat ghrelin response. Participants’ satiety was consistent with what they believed they were consuming rather than the actual nutritional value of what they consumed."So, they were given the same shake, told one was sensible and no-fat, on another occasion told it was a rich, creamy, fatty, indulgent shake. First-off, guess which one they thought tasted better? What was a novel finding, was that despite the same shake, calories, fat, and nutrients, what the study participants thought about it effected the physiological, measurable response. Indulgence meant lower ghrelin, meaning more satisfied, and presumably, less hungry. "Sensible," (aka deprivation) meant that the ghrelin level did not fall. So, in spite of the same intake, these sensible shake drinkers had higher ghrelin levels.Conclusions: "The effect of food consumption on ghrelin may be psychologically mediated, and mindset meaningfully affects physiological responses to food."
"Mindset meaningfully affects physiological responses to food."
Or, put another way, "When the joy goes out of eating, nutrition suffers." - Ellyn SatterAnyway, I remember a study that did the same thing, that is same shake, one labeled indulgent, the other low-fat, but looked at functional MRI or PET scans. The result showed markedly different effects on the brain. Guess which made the pleasure centers light up? The participants who thought they were drinking the indulgent shake experienced more pleasure with the same shake than those who thought it was low-fat. Another study had a similar set-up with full-fat yogurt. One group was eating the same yogurt labeled "low-fat" and they reliably ate more calories for the rest of the day, presumable to make up for those lost calories, also known as the "halo" effect, whereby even the label of "organic" makes people tend to consume more. (Flat ghrelin response perhaps part of the equation?)So, for awhile, I have been convinced that when most folks are told something is healthy, or low-fat, or even organic, they don't enjoy it as much, they miscalculate what they think they should be eating. They over-think it, try to eat based on cognitive, not internal cues. Should and shouldn't muddies the waters, and now this ghrelin information gets thrown in too. So the thinking of the halo effect, and the cognitive miscalculations are on top of perhaps elevated ghrelin levels- that motivate consumption.This is the first study I have seen that shows that there is a physiological mediator, if you will, for those thoughts. (If you know of others out there, please let me know.) That the thinking plays out on a hormonal level, and is why we have to get this head-game out of our eating!!The great irony to me was the last sentence, "Perhaps if we can begin to approach even the healthiest foods with a mindset of indulgence, we will experience the physiological satisfaction of having our cake and eating it too." Forehead slap. Why not approach all foods with indulgence and joy, and perhaps if we do indulge in a piece of cake and eat in a tuned-in way, we will feel satisfied both cognitively and physiologically. We can also feel that a ripe juicy peach is indulgent. When we reject the labels of "good" or "bad" or "healthy" or "unhealthy," and it's just the wonderful world of the variety of foods we get to chose from, when we think a little about nutrition in our meal planning so that we can meet our needs for hunger and fullness, and basic food group kind of thing, then we can begin to get the head-game off the table and eat based on what our mouths and bodies tell us, not our brains. (eating competence.)I can see these folks now labeling fat-free fiber shakes as "indulgent and creamy," but we won't be fooled so easily, and in the meantime the trickery, the sales pitch won't help...What do you think? Where do you think this is headed? How do we begin to get the head-game off the menu?