[kromodor]

Long term probably. I've read tents of studies on the topic and books on similar topic. Junk food has long term effects, non of which are good. They can affect various things, some of which, directly or indirectly, affect higher order thinking, levels of energy, mood, activity and etc.

Also *x increased chance of various debilitating diseases.

Not to sound like a crazy health nut - there are two stupendous studies on the citizens of Okinawa (The Okinawa project) and China (The China study) that leave little doubt on the long term effects of junk foods.

So yes, it can.