The prevalence of obesity has become a serious, worldwide public health problem. Its main cause is in the change of lifestyle having been brought by technological innovations in the fields of food production and processing, distribution systems, computer and information technologies, means of transportation, etc. Obesity raises problems in health care, medical spending, labor market, quality of life, and other areas. Using a panel data in Japan and analyzing effects of overweight and obesity on physical and mental health, we found the following: 1) obesity influences physical and mental health negatively; 2) the effect appears more on physical health than mental health; 3) men tend to be affected physically more than mentally and women mentally more than physically; and 4) the effects of overweight and obesity are noticeable more on workers than non-workers and more on employees than self-employed. Obesity is a problem of dietary habit on one hand and that of social structures on the other. There are many actual and foreseeable problems to be solved to prevent obesity and cope with obesity-related issues. Physical and mental health problem dealt with in this paper is one of them when the number of overweight especially for men in Japan shows a steady growth.
