Department of Ubiquitous Health Informatics, Graduate School of Medicine, University of Tokyo, Tokyo, Japan Department of Diabetes and Metabolic Diseases, Graduate School of Medicine, University of Tokyo, Tokyo, Japan kwaki-tky@umin.ac.jp. Department of Information and Communication Engineering, University of Tokyo, Tokyo, Japan. Department of Ubiquitous Health Informatics, Graduate School of Medicine, University of Tokyo, Tokyo, Japan. Business Development of Healthcare Business Smart-life Solutions Department, NTT DOCOMO, Inc., Tokyo, Japan. foo.log, Inc., Tokyo, Japan. Department of Information and Communication Engineering, University of Tokyo, Tokyo, Japan foo.log, Inc., Tokyo, Japan. Department of Diabetes and Metabolic Diseases, Graduate School of Medicine, University of Tokyo, Tokyo, Japan. Department of Medical Informatics and Economics, Graduate School of Medicine, University of Tokyo, Tokyo, Japan.