Diet carbonated soft drinks were introduced to help consumers lower caloric intake. However, critics suggest that these drinks can provide an excuse to consume more calories, a so-called “Big Mac and Diet Coke” mentality that is consistent with behavioral theories such as moral licensing (e.g., combining a healthy eating choice with an indulgent, less healthy one). Using individual-level food and drink consumer panel data from a major fast-food restaurant chain, we empirically examine meals with a regular carbonated soft drink (CSD) versus a diet CSD. Results after controlling for drink size and demographics show that consumers generally do not order higher total calories from a meal with a diet CSD; rather, we find significant reductions in calorie count, suggesting that within a single meal, diet CSDs can help consumers unwilling to stop drinking CSDs to reduce calories. So, despite popular beliefs to the contrary, policy makers can consider diet-CSD availability as a “calorie-reduction” strategy to lower calorie consumption within a meal.

饮食中添加了碳酸软饮料，以帮助消费者降低卡路里的摄入量。但是，批评者认为，这些饮料可以提供更多卡路里消耗的借口，一种所谓的“巨无霸和健怡可乐”的心理，与诸如道德许可等行为理论相一致（例如，将健康的饮食选择与放纵的饮食，健康程度不高的人之一）。使用来自主要快餐连锁店的个人级别食品和饮料消费者面板数据，我们根据经验检查了普通碳酸软饮料（CSD）与饮食CSD的餐点。在控制了饮料的大小和人口统计后的结果表明，消费者通常不从含饮食CSD的餐点中订购更高的总卡路里；相反，我们发现卡路里数量显着减少，这表明在一顿饭中，饮食中的CSD可以帮助不愿停止喝CSD的消费者减少卡路里。因此，尽管人们普遍认为相反，但政策制定者可以将饮食中CSD的使用视为减少卡路里摄入量的“减少热量”策略。