Extended vs. brief intermittent access to palatable food differently promote binge-like intake, rejection of less preferred food, and weight cycling in female rats.

BACKGROUND

Palatable food access promotes obesity leading some to diet. Here, we modeled the roles of duration, intermittency and choice of access in bingeing, escalation of daily intake, and underacceptance of alternatives.

METHOD

Female rats with ("Choice") or without continuous chow access, received chow or continuous (Chocolate), intermittent (MWF) long (24h, Int-Long), or intermittent short (30min, Int-Short) access to a sucrose-rich, chocolate-flavored diet (CHOC).

RESULTS

Int-Long rats showed cycling body weight; they overate CHOC, had increased feed efficiency on access days and underate chow and lost weight on non-access days, the latter correlating with their reduced brown fat. Int-Short rats had the greatest 30-min intake upon CHOC access, but did not underaccept chow or weight cycle. Individual vulnerability for intermittent access-induced feeding adaptations was seen. Continuous access rats gained fat disproportionate, but in direct relation, to their normalized energy intake and persistently underaccepted chow despite abstinence and return to normal weight. Abstinence reduced the binge-like CHOC intake of Int-Short rats and increased that of continuous access rats, but not to levels associated with intermittent access history. Choice increased daily CHOC intake under Continuous access and binge-like intake under Int-Short access.

CONCLUSIONS

Intermittency and duration of past access to palatable food have dissociable, individually-vulnerable influences on its intake and that of alternatives. With extended access, daily intake reflects the palatability of available food, rather than metabolic need. Ongoing restrictedness of access or a history of intermittency each drive binge-like intake. Aspects of palatable food availability, similar and different to drug availability, promote disordered eating.