In an article in last week’s WSJ, Stanford researcher Robert Sapolsky suggests that there is an evolutionary reason for eating junk food when stressed, and it’s not just humans who do so:
This phenomenon’s occurrence in many species makes evolutionary sense. For 99% of animals, stress involves a major burst of energy use as they, say, run for their lives. Afterward, the body stimulates appetite, especially for high-density calories, to rebuild depleted energy stores. But we smart, neurotic humans keep turning the stress-response on for purely psychological reasons, putting our bodies repeatedly into the restocking mode.
Sapolsky also notes that “our evolutionary legacy” means that “far fewer of us will seek solace in the poetry of Robert Frost than in a pint of double fudge brownie ice cream.”
Hmmm … I suspect that it’s one part evolutionary legacy and one part 24×7 access to hyperpalatable crap!
Weight Maven is written by Beth Mazur. Beth believes that obesity is more symptom than cause and that the real problem is our Western diet -- especially sugar, refined grains, and industrial oils. Beth writes about nutrition, ancestral health, & food policy. And cats! 
Couldn’t agree more, though there is something about when I don’t need to think about it, my stress response chemistry/neuro pathways will be strongly biasing me toward keeping accessible sugar levels up and low GI/GL foods just don’t do that. One issue that arises from this is ‘what’s going on when I’m not thinking about what is the best food for me now?’