d-qn

# read data and replace dots in names with underscores
obesity = read.csv(
  'http://www.stat.berkeley.edu/classes/s133/data/obesity.csv',
  stringsAsFactors = F
)
names(obesity) = gsub("\\.", "_", names(obesity))

# add column with two letter state names and 
obesity = plyr::mutate(obesity, 
  State = str_trim(State),