New research shows medical spending averages $1,400 more a year for an obese person than for someone who's normal weight. Overall obesity-related health spending reaches $147 billion, double what it was nearly a decade ago, says the study published Monday by the journal Health Affairs.Diet and Nutrition.he new Health Affairs study found obesity-related conditions now account for 9.1 percent of all medical spending, up from 6.5 percent in 1998. During that time, the obesity rate rose 37 percent.