I do this trick all the time. If I'm with a friend and want to align our appetites, I ask them if they're hungry, talk about what I would like to eat and then wait.....it usually takes about 20 minutes.
And here is a study to prove it. It claims that although sight and smell were significant in increasing gastric juices in preparation for digestion, it seems the thought of food was stronger.
I would like to elaborate on this further, since it opens up ideas of emotional eating to just bad food habits, and how we can approach these issues via a different way. Thought is subtle and a lot more difficult to control than our senses, although we do it on a regular basis via talk therapy as we know it's a powerful way to change behaviour. However, one aspect of talk therapy, and this is not the case with all talk therapy as mindfulness based ideas are more common these days, however just like the western approach to disease management of the body, it seems traditional talk therapy never really brought the patient in line with how they were receiving and digesting information from their senses; the body was disconnected from the mind. And it became commonplace to see a 'therapist' for years, decades, all their lives.
Ayurveda provides an angle that appears to be a lot more simple and easier to implement, via the purification of the senses. And along with yogic breathing exercises, it seems to be a very powerful ally in working with issues of the mind, where thought resides. Ayurveda recognises that thought feeds on impressions, so the better digested the impression, the better digested the thought.
So rather than the mind trying to work out the mind, and usually with a feebleness at that, Ayurveda does what I like to call 'the backdoor approach', meaning it approaches the feeble king with a trained army of five sense warriors, with positive (filtered) news from lands far and wide. It just seems a hell of a lot easier to work from gross to subtle than the other way around.
So yes, thought is powerful, and especially in the state of affairs these days where our senses have been dulled, which leaves us open to others' suggestion. It should be an invitation to bring the warrior senses up to speed, lest you come hang out with me and I make you eat.....when MY digestion is ready to eat and perhaps not yours.