Sure, some studies have been run, though as an earlier commenter noted, replicability has been called into question. http://www.indiana.edu/~abcwest/pmwiki/CAF

Sure, some studies have been run, though as an earlier commenter noted, replicability has been called into question. http://www.indiana.edu/~abcwest/pmwiki/CAFE/Wang%20-%20Sweet%20future.pdf http://www.indiana.edu/~abcwest/pmwiki/CAFE/Wang%20-%20Sweet... (summary here: https://books.google.com/books?id=evc6jaibNd8C&pg=PT52&lpg=PT52&dq=soda+willpower&source=bl&ots=a8p0KdAysE&sig=WumdW5Zai-ttcnwxDw37TzcpgHM&hl=en&sa=X&ved=0ahUKEwiR3cSd_onXAhVE04MKHdOHBu0Q6AEIRzAJ#v=onepage&q=soda%20willpower&f=false https://books.google.com/books?id=evc6jaibNd8C&pg=PT52&lpg=P...)