I am posting about a study that was discussed in the popular press this week (if I remember correctly, it was an on-line article from a Boston newspaper).  I have not reviewed the research though I did contact the lead author/scientist, Dr. Jason Block to see if a publication is pending.  That being acknowledged, I will summarize the news story and add a few thoughts.
   At the very least, this study on sugar sweetened beverages (SSBs), like soda, juice, sports drinks, flavored whole milk and coffee drinks, offers promising results.  Dr. Block and his research associates tested whether raising the price of SSBs that contain 150 or more calories, would lead to a decrease in purchase of said drinks.  There was a 16% decrease in sales after the price change (1 cent per ounce, so $.20 increase in price).  Without seeing the research article, if there is one, I can't tell you the absolute change in number of beverages sold.  I also don't know what, if anything, the people spent their saved 'soda' money on.  They might have spent the money they did not spend on soda on foods that might be high in sugar or calories, on sugar free drinks, or on nothing. That is an important outcome to assess in these types of studies.
    In a second study, the same team labeled the SSBs with their calorie content and organized the display of drinks by amount of calories.  I assume that the first columns were sugar free items, then low calorie, then high calorie.  In this experiment, sales of low calorie drinks increased by about 11%.
   The results of this work support both the use of calorie labeling and taxation (price manipulation) to change behavior and thus, improve health.  However, I do not know the details of the study, so I make that assertion with some caution.  I would like to know more about any unintended consequences (substituting soda for chips, eg) and whether or not the changes that were seen were able to be sustained over time.  Lastly, this study took place at one work site and the results might be different elsewhere.  
    If/when I hear back about the study itself, I will write a follow up post.  I am very interested in this type of population level intervention.  In other words, putting effort toward changing the environment instead of changing people in one on one interventions (like a diet class).