The Hormone responsible for overeating – Ghrelin
January 25, 2020
Have you ever been in a restaurant, shoved the last bite of your delicious meal into your mouth, despite knowing you are full, but then finding the waiter walking towards you with the dessert menu? You know you shouldn’t eat anymore. You know you shouldn’t get the triple chocolate cake. But you can’t help yourself. You get it and you end up eating the whole thing. As you loosen your belt, you wonder why you just did that.
The University of Texas Southwestern Medical Center conducted a study that suggested that ghrelin, the hormone your body secretes when you are hungry, might act on the brain, thus influencing the hedonistic aspects of eating behaviour – the result being that we continue to eat ‘pleasurable’ foods even when we are full. Researchers Jeffrey Zigman, Mario Perello, and Michael Lutter suggest that ghrelin increases specific rewarding aspects of eating. Previous studies have shown that ghrelin levels are linked with pleasurable feelings one gets from substances, such as alcohol. Zigman explained that the rewards give us sensory pleasure and motivates us to work to obtain them. They also facilitate the reorganisation of our memory, causing us to remember how to obtain the rewards – in other words eating.
In order to study the effects of ghrelin on overeating, the researchers conducted two studies using mice as test subjects. In the first study, the scientists observed whether the mice that were satiated preferred a room where they previously found high-fat pellets versus a room that had regular, bland food. The mice without the ghrelin had no preference, however when the mice were injected with ghrelin, they preferred the room with the fatty food. In the second study, the scientists measured how long the mice would continue to poke their heads into a hole to receive a pellet of high-fat food. This study, similar to the first, was conducted with both ghrelin-injected mice and unaffected mice. The mice with ghrelin spent more time poking their heads into the hole, while the mice without ghrelin gave up sooner.
So, the next time you reach for the dessert menu, ask yourself if you want the triple chocolate cake or if the ghrelin is making you think that you do.