Recent research on novel addiction types suggests that, in addition to hunger, the urge to eat is considerably influenced by environmental cues. Obese individuals have been shown to be more sensitive to these, with subsequent stronger craving and larger portion sizes. Neurobiologically, this has been linked with pathological alterations to cue-triggered motivational responses in the nucleus accumbens (NAc) parallel to those seen in drug addiction. Oginsky et al investigated the effects of a junk-food diet on obesity-susceptible and obesity-resistant rats. Glutamatergic calcium-permeable AMPA receptor (CP-AMPAR) functioning in the NAc showed more rapid and long-lasting (for weeks after cessation of junk-food consumption) increases in the obesity-sensitive group. CP-AMPARs mediate cue-triggered food seeking, and their changes in the brain occurred before weight gain. The data support the concept that ‘junk food addiction’ induced by the consumption of fatty and high-sugar foods may be contributing to the obesity epidemic.