This working paper presents the findings of copy test research on consumer perceptions of heart-health claims in print advertisements for a fictitious cooking oil low in saturated fat, and a vegetable oil spread containing no trans fatty acids. FDA regulations currently ban potentially useful heart-health claims in labeling for many such products, and this restriction also appears to have discouraged similar claims in advertising. One deception-based motivation for the ban would be that the heart-health claims might mislead consumers to believe that the products are healthy in all respects, when in fact they are high in total fat and calories, and their regular use could cause weight gain and associated heart problems unless the products are substituted for less healthy alternatives. Our research tested this deception hypothesis and found no support for it. Adding an explicit heart-health claim to a nutrient content claim (such as “low in saturated fat” or “no trans fats”) did not change consumer perceptions of the caloric content of the tested products or otherwise distort perceptions of the products’ overall healthiness. These conclusions not withstanding, our results also suggest that respondents as a whole, including those who did not see a nutrient content claim or a heart-health claim, underestimate the caloric content of cooking oils. Further, respondents did not appear to understand the significant impact that relatively small daily increases in caloric intake can have on long-term weight gain. Our findings emphasize the need for increased consumer education concerning the caloric content of cooking oils, and the implications of even modest changes in caloric intake, from whatever source, on weight gain and heart health.