Knowing that ingestion of a HFD stimulates ethanol intake (Carrillo et al., 2004), we tested whether ethanol can, in turn, stimulate the ingestion of a HFD, thus creating a positive feedback loop. As shown in Fig. 1, after 21 days of 10% ethanol (1g/kg, i.p.) or saline injection, rats receiving ethanol increased their relative preference for the HFD vs. LFD in a 2-h test, from 39% in the saline group to 60% in the ethanol group [F(1,3) = 5.12, p < 0.05]. An even greater effect was observed in the measure of 24-h intake, which revealed an increase in fat preference from 36% in the saline group to 62% in the ethanol group [F(1,1) = 6.47, p < 0.05]. These results suggest that the relationship between dietary fat and ethanol is bidirectional, with ethanol stimulating fat ingestion in addition to fat potentiating ethanol intake.
