The holiday season is a hard one for anyone watching their weight. The sights and smells of food are hard to resist. One factor in this hunger response is a hormone found in the stomach that makes us more vulnerable to tasty food smells, encouraging overeating and obesity. The article "Gut hormone increases response to food" is in this link :
https://www.sciencedaily.com/releases/2018/12/181212121907.htm