Link between fast food and depression confirmed, not clarified

This article states that around 5% of non-depressed people go on to develop depression when they eat junk food of the baked-goods variety (like croissants, pecans spins and Twinkies) or fast food.

Link between fast food and depression confirmed

The authors assume the link is causal (fast/junk food causes depression), but I don't see why. Many people only eat fast food and carb-rich junk food when they're already depressed and want the temporary solace (and serotonin/insulin hit) of comfort food. It might be smarter to eat more trail mix, olives and avocados when we're depressed, and leave out the Twinkies, but the fact is they cost more.

So, is the fast food/junk food self-medication for depression, contributor to depression, or both? It makes more sense to view it as a sign that something is amiss, rather than leaping to the conclusion that fast/junk food itself is the problem.

When people need to self-medicate, they're going to find a way. And at least fast food is not going to cause as many accidents as alcohol, as much ruin as harder drugs, or as much disease as compulsive sex -- all of which are popular forms of self-medication for depression.

Something to consider... We need not leap right to the blaming mentality. We can treat these changes in habits as useful clues instead.