Maternal obesity is recognized as one of the largest contributors to compromised health during pregnancy. Lifestyle interventions in obese pregnant women may be able to reduce gestational weight gain (GWG) but have shown limited success in improving pregnancy and neonatal outcomes. Lack of statistical power, poor compliance and inconsistency in inclusion BMI and setting across studies may be some of the reasons. Since pregestational BMI is the single most important predictor of obesity-related complications, the metabolic profile in the first trimester of pregnancy may play a very important role. Observational studies have shown that interpregnancy weight loss reduces the risk of macrosomia in a subsequent pregnancy. Future lifestyle randomized controlled trials should target the prepregnant state and examine the effect on maternal and neonatal outcomes.