The Cooper Institute

Founded in 1970 by the "Father of Aerobics"
Kenneth H. Cooper MD, MPH


Food Prices and Calories

Posted in
Eat better

Thursday, Mar 11, 2010

There’s a big beverage brouhaha brewing in New York state.  It has nothing to do with coffee or beer.  A proposed tax on soda is at the center of this storm.

Local (e.g., Philadelphia) and state governments such as New York are looking to raise revenues and reduce waistlines by taxing sweetened beverages.  The proposed taxes range from 12 to 24 cents per 12-ounce container.  As expected, soda manufacturers are all afizz over this development.

We won’t opine about whether or not taxing soda is worthy public health idea.  We’ll save that for another blog on another day.   But there is recent research that suggests that manipulating the price of foods may change – in surprising ways – what people buy. 

Testing Effects of Food Prices

Scientists at the University of Buffalo used a very innovative research design to test how reducing the costs of healthy foods (i.e., subsidizing) or increasing the cost of less healthy foods (i.e., taxing)  would affect the types of foods moms selected for their families1.  The researchers simulated a trip to the supermarket by setting up a room with photos of 68 foods and beverages.  One-half of the foods were healthy and the other one-half were less healthy.  The food photos also had the nutrition information and price for the respective food. 

Forty-two mothers with at least one child living at home each went “shopping” through the “store” five different times.  They were given a spending limit (the same amount for each time) based on the size of their family and they had to spend it all.  Each time a mom went shopping the prices were different.  During some trips the prices of healthy foods were lowered (i.e., they were subsidized).  On other trips, the food prices on less healthy foods went up (similar to being taxed).  After each trip through the simulated store, researchers calculated the nutrient composition of the foods a mom “bought.” 

Food Subsidies or Taxes – Which Works?

The results very clearly showed that taxing less healthy foods reduced the calories and fat and increased the protein in the mom’s shopping carts.  The moms purchased less of the less healthy foods AND surprisingly, increased their purchase of the healthier foods!  What did subsidizing the price of the healthier foods do?  The moms bought more of the healthy stuff as expected but they also used their “savings” on the healthier foods to purchase more of the less healthy foods!  This led to an actual INCREASE in total calories purchased.  The opposite of what most families today need to do. 

So maybe New York, Philadelphia, and other places are on to something with their budget proposals that call for taxes on sodas.  But should soda and other sweetened beverages be the only foods targeted?  Tune in next week for a continuing chapter in the soda tax saga. 1 Epstein LH et al.  The influence of taxes and subsidies on energy purchased in an experimental purchasing study.  Psychological Science.  Published online 5 February 2010.  DOI 10.1177/0956797610361446.