Maternal obesity has long-term consequences for the development of hypothalamic neurones involved in energy homeostasis and the metabolic profile in offspring. In the present study, we compared the effects of maternal obesity induced by longstanding high-fat diet (HFD) with milder postnatal overfeeding during suckling induced by litter size reduction. Female Sprague-Dawley rats consumed chow (C) or HFD. On postnatal day 1, litters from chow dams were adjusted to three per dam (small litter, CS) versus 12 control (normal litter, CN). Litters from HFD dams were adjusted to 12 per dam and fed HFD after weaning to induce obesity (HN). Thus, two degrees of maternal overnutrition were produced (CS and HN). To test whether postweaning diet can amplify the effects of maternal obesity, male offspring weaned onto chow or HFD were followed to 21 weeks. Maternal postnatal overnutrition (CS) and HFD-induced maternal obesity (HN) increased body weight and fat mass in offspring compared to those from control dams (CN). Significant glucose intolerance was induced by both degrees of maternal overnutrition, but only in offspring consuming HFD. HFD-induced maternal obesity (HN) was linked to increased offspring leptin, insulin, lipids, insulin resistance and hyperphagia, and was exaggerated by postweaning HFD. No effect of maternal postnatal overnutrition (CS) was seen on these parameters. Hypothalamic signal transducer and activator of transcription-3 and suppressor of cytokine signalling-3 mRNA were significantly elevated by maternal HFD (HN) in the HFD-fed offspring. The data obtained suggest that even mild maternal overnutrition (CS) led to increased adiposity, glucose intolerance and altered brain appetite regulators in offspring. A greater impact of HFD-induced maternal obesity was evident. Marked additive effects were observed when animals consumed a HFD postweaning.