Virtually all Westerners fear terrorism far more than they fear dying out of complications resulting from eating junk food, even though the largest modern terrorist attack, 9/11, killed the same number of Americans that die in about 3 days from problems associated with obesity alone.
Eschewing the standard explanation of evolutionary psychology, Stentor talks about the problem in sociological terms, coming from risk perception theory:
I don’t think a single direct explanation, of the type Roberts proposes, is sufficient here. Cultural theory tells us that we fear risks that are immoral. Moral outrage arises from violation of accepted social structures (the generalized building blocks of which are doubtless evolved, but whose specific applications are contingent and cultural). According to Alan Fiske, there are four such building blocks — ingroup/outgroup boundedness, ranking, equality, and freedom. Thus I would suggest there are at least four key triggers of fear: infiltration/profanity, insubordination, unfairness, and tyranny. Terrorism is able, in our culture, to set off all four triggers (albeit different ones to different extents for different people — a crucial caveat in all such discussions). Poor diet can perhaps trigger one, but even that is mitigated by our modern liberal (in the sense of the broad historical tradition, not the contemporary political agenda) culture.
Terrorism is infiltration — unbeknownst to us, outsiders are able to slip into our society, exploiting our institutions in order to destroy them. Terrorism is insubordination — there’s an established pecking order in the world, in which the USA is the alpha male, and organized states with uniformed armies stand above non-state actors. But terrorism is precisely an attempt to overturn this order. Terrorism is thus also unfairness — terrorists refuse to play by the post-Westphalia rules of political struggle, inserting both themselves and civilians into a form of conflict that is supposed to be reserved for uniformed armies. Finally, the particular form of terrorism we face now is tyranny — the popularity of the term “Islamofascism” shows how we concieve the terrorists’ goal as the establishment of a theocracy repressing legitimate freedoms. (Anarchist terrorism would lack this trigger, but it would get a double hit on the “insubordination” trigger, since it aims at the overthrow of all rankings.)
Poor diet is not tyranny — indeed, it’s defended as an expression of personal freedom to eat what we please. Poor diet is not unfair — indeed, criticism of poor diet is (inaccurately) derided as elitist and proposing solutions beyond the budgets of normal people. Poor diet is not insubordination — indeed, eating Big Macs shows you’re a regular joe, whereas eating tofu is either elitism or the converse crime of effeminacy. One can potentially see poor diet as a form of infiltration/profanity, in a way similar to how sodomy is seen by some as a crime against (an infiltration or profaning of) one’s own body. However, that framing has little traction in a modern liberal culture (even sodomy is more feared due to being seen as insubordination). We insist that one’s body is one’s property, to be done with as we like. What’s more, unhealthy foods are accepted parts of our society, so it’s difficult for the average American to conceptualize them as dangerous outsiders.
This looks like a fairly sound explanation to me, but I’m not sure it’s necessary. One of the basics of risk perception is that we fear risks we don’t control more than risks we do control. People fear plane crashes far more than they fear car accidents, even though the only trigger that applies to plane crashes is, possibly, freedom, since airline passengers surrender all control to the pilots.
So it could just boil down to the idea that terrorism is an unknown, uncontrollable foreign risk, whereas poor diet is a known, controllable, local risk. It’s telling that the people who are trying the most to get people to worry about poor diet present it in terms of a pernicious corporate entity making people eat poorly, i.e. a violation of bodily autonomy akin to rape.
Still, the division of fear into four different kinds of values makes a fair amount of sense. In particular, it explains the way liberalism on immigration and liberalism on other issues, such as homosexuality and religion, are largely orthogonal in Europe: immigration triggers fear of infiltration, whereas secularism and homosexuality trigger fear of insubordination; indeed, in the US, where immigrants tend to assimilate to mainstream culture faster than in Europe, and where on the other hand atheism and homosexuality seem foreign, these two kinds of fears merge, and people who are liberal with respect to one are usually liberal with respect to the other.