Richard Lowe, professor of psychology at Drexel University in Philadelphia, says neuroimaging studies have shown that in the presence of high-fat, high-sugar or high salt food, areas of the brain related to pleasure ‘‘light up’’, in a similar way to the brain changes seen in drug or alcohol addicts. The release of dopamine, a chemical strongly associated with the brain’s reward system, is also involved.

Ghrelin is a hormone normally produced by the stomach when the body needs energy, to stimulate feelings of hunger; but scientists have found it is also released in the presence of high-fat, high-sugar foods – even when the body does not need calories. The latest studies, from Oregon Research Institute, indicate that with time, dopamine release in the presence of such foods gets stronger, but starts to decline when we actually consume them. In other words, we need more of these foods to get our ‘‘hit’’.

via Why we can’t help finishing off the whole can of Pringles.