Apparently, scientists have now discovered ghrelin’s role in meal initiation and it’s entrainment to habitual meal patterns. Funny, because I’ve been talking about this since I started the blog. Judging from the quick look through my collection of ghrelin related research papers, it seems the earliest paper mentioning this effect of ghrelin in humans is from 2001. The entrainment of ghrelin is part of what makes the 16 hour fast so easy after a few days adaptation.
Though it’s not mentioned in the link, ghrelin has other interesting effects as well, such as stimulating brain functions of spatial learning and memory development. From an evolutionary perspective this makes sense; the urge to find food may create more competitive skills to ensure survival.
In a similar vein, the metabolic increase (via incrased norepinephrine/epinephrine) that occurs during short term fasting is a function of the body telling you to not sit on your ass, but go out and find food – another mechanism selected for during evolution. Yes, you read that right, “starvation mode” is a bunch of hokum, unless we’re talking long term fasting (>72 hrs).
Either way, the link might be worth a read if you’re not familiar with ghrelin. Will at least provide you with some backup material when people ask you why you aren’t starving during the fast.
And when someone asks you why they’re constantly hungry on their six meal-a-day-foo-foo-meal-regimen, you can refer them to dr Silver –
If you eat all the time, ghrelin secretion will not be well controlled,” said Silver, the paper’s lead author and the principal investigator of the study.
