More than two-thirds of women during childbearing years (20–39 years old) are overweight or obese in the United States, with protein intake among 20–49-year-old women being 1.6 times higher than recommended (75.4 g/day versus 46 g/day) that can be considered as a relatively high-protein diet (HPD). Both gestational obesity and HPDs during gestation adversely affect offspring health. This study investigates the impact of HPDs fed during gestation and lactation on obese mothers and their offspring in Wistar rats. Dams randomized to either a normal-protein diet (NPD) or HPD (n = 12/group). Pups from each maternal group were weaned to either NPD or HPD for 17 weeks (n = 12/group). No effect of maternal or weaning diet on food intake, body weight, or body fat/weight ratio was observed. However, NPD dams exhibited higher glucose area under the curve compared with HPD dams (p < 0.03). At weaning, offspring born to NPD dams showed higher fasting plasma glucose (P < 0.03) and insulin/glucose ratio (P = 0.05) than those born to HPD dams. The Homeostasis Model Assessment of Insulin Resistance (HOMA-IR) index was higher in offspring born to NPD dams (P < 0.04) and weaned to NPD (P < 0.05) at week 17. These findings underscore the role of high-protein maternal and weaning diets in pregnancy outcomes for obese mothers, particularly in glucose homeostasis, although gestational obesity may overshadow other parameters. Further research is needed to fully understand the impact on both maternal and offspring health and their underlying mechanisms in this context.

Gestational obesity has major negative impacts on both mothers and their offspring. More than two-thirds of women of reproductive age in the United States are overweight and/or obese. We previously reported that the source of protein in the maternal diet influences the phenotype of offspring born to normal-weight dams. However, whether it has the same effect in obese mothers was unclear. The casein- and soya protein-based diets were fed to obese pregnant Wistar rats and compared for their effects on characteristics of the metabolic syndrome in male offspring. Dams randomized to either a casein (CD) or soya protein (SD) diet (n 12). Pups were weaned to either a CD or SD for 16 weeks. Offspring of SD dams had higher birthweight (P < 0⋅01). Glucose metabolism was not altered at birth but fasting blood glucose (FBG) (P < 0⋅02), insulin (P < 0⋅0002), insulin/glucose ratio (P < 0⋅03), and HOMA-IR index (P < 0⋅0002) were higher in offspring of SD dams at week 17. The pulse rate was higher in dams (P < 0⋅03). Food intake and body weight of offspring were affected by interactive effects of time and dams’ diet (P < 0⋅05). Food intake was not influenced by maternal diet, but it was higher in pups weaned to SD dams (P < 0⋅03) The results of this study indicate that although the source of protein in the maternal diet is still an influencing factor in the outcome of the pregnancy in obese mothers, gestational obesity may mask this effect possibly by imposing general detrimental effects on measured parameters regardless of the source of protein in maternal diet.