Maternal obesity is becoming more prevalent. We used borderline hypertensive rats (BHR) to investigate whether high fat diet at different stages of development has adverse programming consequences on metabolic parameters and blood pressure. Wistar dams were fed a high or low fat diet for 6 weeks prior to mating with spontaneously hypertensive males, and during the ensuing pregnancy. At birth, litters were fostered to a dam from the same diet group as during gestation or to the alternate diet condition. Female offspring were weaned onto either control or "junk food" diets until about 6 mo of age. Rats fed the high fat junk food diet were hyperphagic relative to their chow-fed controls. The junk food fed rats were significantly heavier and had greater fat pad mass than those rats maintained on chow alone. Importantly those rats suckled by high fat dams had heavier fat pads than those suckled by control diet dams. Fasting serum leptin and insulin levels differed as a function of the gestational, lactational and post-weaning diet histories. Rats gestated in, or suckled by high fat dams, or maintained on the junk food diet were hyperleptinemic as compared with their respective controls. Indirect blood pressure did not differ as a function of post-weaning diet but rats gestated in the high fat dams had lower mean arterial blood pressures than those gestated in the control diet dams. The post-weaning dietary history affected food-motivated behavior; junk food fed rats earned less food pellets on FR and PR schedules than chow fed controls. In conclusion, the effects of maternal high fat diet during gestation or lactation are mostly small and transient. The post-weaning effects of junk food diet were evident on the majority of the parameters measured including body weight, fat pad mass, serum leptin and insulin levels, and operant performance.