Obesity Social Network (IMAGE) University of California - San Diego Caption A social network map of 2,200 people, the largest group of connected individuals in the Framingham Heart Study, in the year 2000. Each circle represents one person, and the size of each circle is proportional to that person's body-mass index (BMI). Yellow circles indicate people who are considered medically obese and green circles indicate people who are not obese. Lines indicate family and friendship ties. Credit Figure courtesy of James Fowler, UC San Diego. Usage Restrictions Only with coverage of the Christakis-Fowler study and with credit. License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.