From PhysOrg:
You're trying to decide what to eat for dinner. Should it be the chicken and broccoli? The super-sized fast-food burger? Skip it entirely and just get some Rocky Road? Making that choice, it turns out, is a complex neurological exercise. But, according to researchers from the California Institute of Technology (Caltech), it's one that can be influenced by a simple shifting of attention toward the healthy side of life. And that shift may provide strategies to help us all make healthier choices—not just in terms of the foods we eat, but in other areas, like whether or not we pick up a cigarette. Their research is described in a paper published in the July 27 issue of the Journal of Neuroscience.
When you decide what to eat, not only does your brain need to figure out how it feels about a food's taste versus its health benefits versus its size or even its packaging, but it needs to decide the importance of each of those attributes relative to the others. And it needs to do all of this more-or-less instantaneously. When the dorsolateral prefrontal cortex (dlPFC) is active, it allows the ventral medial prefrontal cortex (vmPFC) to take into account health benefits as well as taste when it assigns a value to a particular food.
More here.