  To use social media for health-related analysis, one key step is the
detection of health-related labels for users. But unlike transient conditions
like flu, social media users are less vocal about chronic conditions such as
obesity, as users might not tweet "I'm still overweight". As, however,
obesity-related conditions such as diabetes, heart disease, osteoarthritis, and
even cancer are on the rise, this obese-or-not label could be one of the most
useful for studies in public health.
  In this paper we investigate the feasibility of using profile pictures to
infer if a user is overweight or not. We show that this is indeed possible and
further show that the fraction of labeled-as-overweight users is higher in U.S.
counties with higher obesity rates. Going from public to individual health
analysis, we then find differences both in behavior and social networks, for
example finding users labeled as overweight to have fewer followers.
