In recent news, food combinations involving fats and carbs have been stated by researchers to have crazy awesome effects on the human brain compared to when foods are only fat alone or carb alone. Based off of some experiments by these researchers, where real-time brain scans are used to see how certain foods people are familiar with are chosen, it can possibly provide an explanation as to why we tend to overeat when not hungry. Ever craved so bad for that super cheesy pizza, sweet marinara sauce, and all the other fixings of your favorite pizza? What about "healthier food," have you ever craved for a salad? For many, most likely not.
Furthermore, based off the research, it was shown that if fat was the main ingredient or carbs, the combination of the two as an option was much, much greater.
For the original research, check it out here!