I'm not aware of any such study, however there was this: http://www.cnn.com/2010/HEALTH/11/08/twinkie.diet.professor/index.html http://www.cnn.com/2010/HEALTH/1

I'm not aware of any such study, however there was this: http://www.cnn.com/2010/HEALTH/11/08/twinkie.diet.professor/index.html http://www.cnn.com/2010/HEALTH/11/08/twinkie.diet.professor/... In which a man loses 27lbs on a diet of twinkies and was even healthier overall according to all metrics. Between this and personal experience I'm prepared to say that as far as weight loss is concerned it really doesn't matter. Granted, different foods may have an effect on mood, energy level, and satiety which will all contribute to the CO part of the CICO equation, but all other variables kept constant a calorie is a calorie.