Low-calorie products are increasingly popular with consumers. To demonstrate the low calorie advantages, companies often advertise “product calorie lower than an apple” or “lower than a banana”. Current research argues that when the calorie counts of comparison objects is fixed, comparison with vices(vs. virtues)can increase consumer purchase intention to the low-calorie products. This is because consumers categorize low-calorie products as virtues based on the heuristic belief that "healthy = low-calorie". So we expect consumer will perceive more calorie discrepancy when compared with vices, which resulting in lower calorie estimation and higher purchase intention. Currently through two study, we verified the main effect and found this effect is mediated by calorie perceived discrepancy. Our research has strong practical implications. We found a better way to promote the low-calorie food. It also shows that currently some corporate practices (informing products calorie content when comparing) may be inappropriate.