Food prices and obesity

Fascinating study by three economists affiliated with NBER concerning how food prices are linked to obesity.  They looked at a national sample of 12 to 18-year-olds and examined how clinical measures of body mass index and percentage body fat related to food prices in their county.  The key findings were that

1. Youths who lived in counties with expensive calories were less obese than those who lived in counties with inexpensive calories.  This applied to both calories associated with foods purchased to be consumed at home and calories purchased at fast-food restaurants (McDonald's, Pizza Hut and KFC, to be precise). 
2. Obesity was lower in counties with inexpensive prices of fruits and vegetables than in those where fruits and vegetables were more expensive.

Over the last 30 years, food prices -- both overall and for fast-food in particular -- have been falling, making them a prime suspect as a cause of rising obesity.  Prices of fruits and vegetables have been rising, so this re-enforces the overall trend.  

Over the centuries, falling food prices have proven to be a blessing, freeing much of the world's population from the most fundamental concerns about subsistence.  This may no longer be true as our society adopts more sedentary lifestyles.  Expect to see more discussion of calorie taxes in the future, along with exercise credits.