- Low in nutritional value (dusting something with micronutrients doesn't count, Kellogg)
- Low in quality ingredients (cheap), using chemicals and highly processed materials as substitutes for actual food
- Lacking in good flavor, instead opting to overload the consumer's lizard brain via an addictive substance (sugar, fat, caffeine, oil, whatever the hell those sugar substitute petrol products are, specific texture combos, see flavorology for more on the concept)
- Made to be eaten quickly and in caloric excess
- Mass produced
I'd say the first three are required for it to count, mass production just makes it more obvious, and being eaten quickly tends to be a side effect of the sensory overload. The food is not made with love, be it for the recipient or for the craft, it is but soulless slop to get the masses to eat as much of their product as possible. McDonalds and the Twinkie both embody these vices. They don't really taste good, but they hit you with so much grease, oil, and sugar that your brain can't help but register it positively, enticing you to eat more all while providing next to nothing other than calories and regret. The goal is your money, the ramifications be damned.