The aim of the communication was to present the baseline data from incidence of obesity, eating habits, physical activity and sedentary behaviour, before ELSa, interventional Portuguese health program. The sample was composed of 496 children (238 girls and 258 boys) with an average 7.7 (± 2.5) years of age. Thinness, overweight and obesity were calculated by using the BMI and the cut off of Cole et al., 24 h dietary recalls and a general questionnaire was completed by the parents to provide information about eating habits, sedentary behaviour and physical activity. The results indicated high incidence of overweight and obesity, many hours in screen activities and low level of physical activity. The eating habits seemed healthy, but our children's lifestyles were sedentary. To combat the high incidence of obesity it is very urgent to design a multi-level intervention aimed to modify key behaviours: physical activity, screen time and nutrition.