I just came across a study they did at Cornell University and it took place in an Italian restaurant! They had people pay either $4 or $8 for a meal and rated their satisfaction.
They used a buffet so people got exactly the foods they wanted but when they paid 4 dollars, they had the feeling that they overate (though they didn’t more than the other group) and had some guilt associated with it. When they paid 8 dollars, they reported that they liked the food more! Here’s the article.