The effects of prenatal exposure to a 'junk food' diet on offspring food preferences and fat deposition can be mitigated by improved nutrition during lactation.

Exposure to a maternal junk food (JF) diet in utero and during the suckling period has been demonstrated to increase the preference for palatable food and increase the susceptibility to diet-induced obesity in adult offspring. We aimed to determine whether the effects of prenatal exposure to JF could be ameliorated by cross-fostering offspring onto dams consuming a standard rodent chow during the suckling period. We report here that when all offspring were given free access to the JF diet for 7 weeks from 10 weeks of age, male offspring of control (C) or JF dams that were cross-fostered at birth onto JF dams (C-JF, JF-JF), exhibited higher fat (C-C: 12.3 ± 0.34 g/kg/day; C-JF: 14.7 ± 1.04 g/kg/day; JF-C: 11.5 ± 0.41 g/kg/day; JF-JF: 14.0 ± 0.44 g/kg/day; P < 0.05) and overall energy intake (C-C: 930.1 ± 18.56 kJ/kg/day; C-JF: 1029.0 ± 82.9 kJ/kg/day; JF-C: 878.3 ± 19.5 kJ/kg/day; JF-JF: 1003.4 ± 25.97 kJ/kg/day; P < 0.05) than offspring exposed to the JF diet only before birth (JF-C) or not at all (C-C). Female offspring suckled by JF dams, despite no differences in food intake, had increased fat mass as percentage of body weight (C-C: 19.9 ± 1.33%; C-JF: 22.8 ± 1.57%; JF-C: 17.4 ± 1.03%; JF-JF: 22.0 ± 1.0%; P < 0.05) after 3 weeks on the JF diet. No difference in fat mass was observed in male offspring. These findings suggest that the effects of prenatal exposure to a JF diet on food preferences in females and susceptibility to diet-induced obesity in males can be prevented by improved nutrition during the suckling period.