Food security refers to proper access to sufficient and nutritious food. Despite the claim that Bangladesh is self sufficient in food, the real scenario, as evident, is that a big portion of our population lack in sufficient calorie. An attempt has been made through this study to determine the causes of this lack in sufficient calorie i.e., food insecurity in rural Bangladesh by using data from the project “Chronic poverty in Rural Bangladesh-2009”. A Binary Logistic Regression model has been used to investigate determinants of food insecurity. Households are defined as food insecure(1) if calorie consumption per day per capita is less than 2122 kcal and food secure(0) otherwise. From our investigation and empirical analysis it is found that despite of having increasing trend both in per capita food production and food availability, many of our people lack in energy balance. That is, sufficiency of food alone doesn’t guarantee an end of hunger. Household size, dependency ratio, land assets of the households and per capita monthly income are found statistically significant for such an imbalance. Moreover, result from Receiver Operating Characteristic (ROC) curve suggests that our fitted model is fairly discriminating.