In reply
We thank Ludwig et al for their letter and regret that they were misled by one of our speculations in the "Comment" section of the article.1 We concluded from our cross-sectional survey that "increased levels of television viewing and soda intake are associated with a higher prevalence of overweight and obesity among sixth- and seventh-grade schoolchildren." In the "Comment" section, we speculated on reasons for an association between diet soft drinks and obesity—one of which was that it might not have been the calories in the beverage alone but the caloric intake associated with a child's general snacking behavior that could have led to obesity. In the report of their longitudinal study, Ludwig et al2 assessed the association with diet drink consumption only while controlling for other calories. The study by Raben et al,3 comparing supplementations of sucrose and artificial sweeteners in overweight adults, and by Tordoff and Alleva,4 studying the effect of adding soda to the diet in adults, are not comparable with our observational study. In the Santa Barbara Study, those who consumed 3 or more diet drinks per day were more obese than those who consumed fewer than 3 regular or diet soft drinks per day, suggesting that it may be the soft drink consumption behavior, with its associated eating behaviors, that is associated with obesity. This is an open question that cannot be answered with our data set. It was unfortunate that Ludwig et al misconstrued our comment as a statement of our findings.