In a study done at Yale in 2011, researchers studied the effects of the hormone ghrelin in response to either an ‘indulgent’ or ‘sensible’ shake. First, what is ghrelin? In the words of the researchers, “Ghrelin is an essential indicator of energy insufficiency. When energy intake is low or the stomach is empty, ghrelin is secreted from the endocrine cells of the stomach and transported in the bloodstream to the brain, where it binds with receptors in the arcuate nucleus and the ventromedial hypothalamus to produce the sensation of hunger and motivate consumption. As energy intake increases and nutrients are detected in the gastrointestinal tract, ghrelin levels are suppressed, thereby signaling to the brain via neural and endocrine mechanisms to reduce appetite and increase feelings of satiety.” In layman’s terms, ghrelin is a gut peptide that regulates our appetite.
Traditionally appetite regulation has only been looked at through the lens of calories. A higher calorie, more satiating meal will increase ghrelin while the opposite will happen with a lower calorie meal. While this makes logical sense, it’s not that straightforward.
Subjects were given two shakes at two different time points. One shake was touted as a high calorie, “indulgent” shake. The other was touted as a low calorie, “sensible” shake. In reality, both shakes were exactly the same. Ghrelin was intravenously measured before, and after ingestion of the shake at two time points. Specifically, 20 (pre shake), 60 (post shake) and 90 minutes (post shake).
The results were pretty astounding. Subjects had a steeper rise in ghrelin during the anticipatory period before the indulgent shake followed by a significantly steeper decline in ghrelin post drinking the shake. However, “when drinking the shake in a sensible mindset, participants exhibited flat or slightly increased levels of ghrelin over the course of consumption suggesting that, despite consuming the same nutrient contents, they were not physiologically satisfied.”
As a coach and a physique athlete, this research is incredibly important for me to understand. Simply how we view our food can determine levels of satiety, effect cravings and potentially derail progress. Since we are bombarded daily with both “indulgent” and “healthy” labels, this is important for consumers (all of us!) to understand.
If you’re interested in the full text and want to get your nerd on, click here to read. Thank you for reading! We hope you find this informative and helpful!
Laurin Conlin, Founder and Coach at Team LoCoFit
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