That is, we repeat once again, with the strengthening of the signal chain associated with the "hunger hormone", the animals grew fat not due to overeating, but due to the accumulation of fat. Then it turns out that the increase in the level of ghrelin before a meal occurs not so much in order to tune the behavior to search for food, but in order to prepare the body for receiving and storing calories.
But what then about the first part of the work, in which hormone injections just stimulated eating behavior? The authors of the work suggest that the whole thing is in too much excess of ghrelin, which is formed in the body - after all, here an external portion is added to some of its internal level - and in this case, appetite stimulation is probably some kind of side and not quite natural reaction.
Other researchers admit that the new results on ghrelin, published in Science Signaling, are quite interesting, but in order to finally redefine the function of the "hunger hormone", additional experiments are needed. What interest in all this could be for those who are not involved in hormonal signals? Of course, we are talking here about food, about calories, but after all, no practical specifics can be extracted from this yet.
It should be noted here that, on the one hand, such studies are the best illustration of how a scientific search takes place and how many nuances are discovered when we try to clarify our ideas about a particular biological object (be it a hormone, a biochemical reaction, a cell or an animal) ... The interpretation of the results is not limited to a refutation or confirmation, and sometimes all confirmations or refutations remain in place, it just turns out that they relate to some kind of artificial or secondary manifestations.
On the other hand, the same "hunger hormone", as you might guess, is quite suitable as a target for some "means for losing weight", "drugs for normalizing metabolism", etc. But is it possible to use such means if we are still do not fully understand what exactly ghrelin does?
To summarize, we can say that when we suddenly suddenly discover some kind of gigantic economic prospect, we should always remind ourselves that the world is more complicated than it seems, especially when it comes to molecules, atoms, cells, etc.
Of course, someone will say that science never figures out anything to the end, and that how many people, so many opinions, and other similar pearls of folk wisdom, however, if things really were like this, we would still live in caves, not being able to figure out anything to the end and exchanging various opinions.