Discrimination against people who are overweight can reduce their opportunities for education, a good job and a favorable income trend, and also increase the risk of unemployment. The aim of the study is to analyse the socio-economic consequences of overweight that appears during youth. The study covers 450,000 men, born in Sweden 1952-61, who underwent a medical examination for compulsory military service at the age of 18 or 19 (during 1970-80). The socio-economic consequences of overweight are studied longitudinally for 20-30 years following conscription. Research questions: (1) Do men who are overweight since youth show lower educational attainment than men of normal weight? (2) Do overweight men show a poorer personal-income trend than men of normal weight? (3) Do overweight young men show weaker upward, and sometimes even downward, social mobility than young men of normal weight? (4) Is the risk of unemployment greater among overweight men than among men of normal weight? The study is based on record linkage between several Swedish national registers. Information on body mass index (BMI) and aptitude is to be taken from the National Conscription Register, and on education, occupation, employment status and income from registers administered by Statistics Sweden. It is estimated that the study will encompass 31,500 men with moderate overweight, and 4,500 men with severe overweight (obesity). Knowledge of the personal-income trend and social mobility of overweight and obese people can be of great significance in societal debate, for employers and employees and most likely in community planning.