There is no such thing as junk food. Food is food. When I go backpacking, I eat crud I would never eat at home, stuff loaded with fat, salt, and sugar. Dinner might consist of couscous with ‘Vienna’ sausages. If you are an American you know what the latter are: morsels of mystery meat laden with fat and sodium. But when you are schlepping 40-50 lb loads over 12,00 foot passes, all the while sweating like a pig, this is is exactly what you need. You need fat, sodium, sugar, and strong coffee laced with more sugar. The frou-frou salad and green tea can wait for later.
Tell the food fascists of San Bancisco and elsewhere to shove it.