Researchers have found that dietary restraint increases food cravings and may contribute to loss of control over eating. Negative mood states often precede food cravings and binge eating. In the present study, we tested the influence of a prolonged food deprivation period over emotional states and food cravings. Twenty-one bulimia nervosa participants and 20 healthy women participants were asked to refrain from any eating for 20 hours and reported, at baseline, after 6 hours and at the end of the fasting period, their mood and craving states. Food consumption was also measured. Fasting increased food cravings in both groups but increased negative mood in healthy women only. Bulimia nervosa participants reported improved mood following food deprivation. Whereas Bulimia nervosa and healthy women participants ate moderate and similar amounts of food following the 20-hour fasting period, food cravings were significantly associated with the number of calories ingested. These findings are congruent with self-regulation theories that predict that prolonged fasting may reduce negative emotions in women with bulimia nervosa. Copyright © 2012 John Wiley & Sons, Ltd and Eating Disorders Association.