Currently more than 1 billion adults are overweight -and at least 300 million of them are clinically obese. Article from World Health Organisation mentioned that obese is the major cause for Diabetics, cardio vascular problem and cancer. Change in food habits and lack of physical activities are the main reason for obese. Daily food choices affect our short term and long term health. By monitoring food intake we can assess the person food habit, in this paper we discussed and analyse various method involving energy intake and energy expenditure and need for accurate long term dietary assessment technique for free living individuals. © 2015 IEEE.